Impinj, Inc.

Patent Trials and Appeals Board

Aug 16, 2021

IPR2020-00553 (P.T.A.B. Aug. 16, 2021)

Trials@uspto.gov Paper No. 50
571.272.7822 Entered: August 16, 2021

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________

NXP USA, INC.,
Petitioner,

v.

IMPINJ, INC.,
Patent Owner.
____________

IPR2020-00553
Patent 8,600,298 B1
____________

Before BRIAN J. McNAMARA, ROBERT J. WEINSCHENK, and
KEVIN C. TROCK, Administrative Patent Judges.

TROCK, Administrative Patent Judge.

JUDGMENT
Final Written Decision
Granting-in-Part and Denying-in-Part Patent Owner’s Motion to Amend
35 U.S.C. § 318(a)

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INTRODUCTION
We have authority to hear this inter partes review under 35 U.S.C.
§ 6. This Final Written Decision issues pursuant to 35 U.S.C. § 318(a) and
37 C.F.R. § 42.73. For the reasons discussed herein, Patent Owner’s
Revised Non-Contingent Motion to Amend is granted-in-part as to the
cancellation of claims 1–5, 8–12, and 15–19 (the “challenged claims”) of
U.S. Patent No. 8,600,298 B1 (Ex. 1001, “the ’298 patent”), and denied-in-
part as to proposed substitute claims 22–36 (the “substitute claims”).
A. Procedural History
NXP USA, Inc., (“Petitioner”) filed a Petition for inter partes review
of claims 1–5, 8–12, and 15–19. Paper 1 (“Pet.” or “Petition”). Impinj, Inc.,
(“Patent Owner”) filed a Preliminary Response, Paper 9 (“Prelim. Resp.”).
We instituted inter partes review of all challenged claims on the grounds
presented in the Petition. Paper 15 (“Institution Decision” or “Dec.”).
After institution, Patent Owner filed a Non-Contingent Motion to
Amend, cancelling all the challenged claims and proposing substitute claims
22–36. Paper 24, 4–5 (“Mot. to Amend.”). Petitioner thereafter filed an
Opposition to the Motion to Amend. Paper 28 (“Pet. Opp.”). We then
issued Preliminary Guidance to Patent Owner’s Non-Contingent Motion to
Amend. Paper 29 (“Prelim. Guid.”). Patent Owner filed a Reply in support
of the Non-Contingent Motion to Amend. Paper 30 (“PO Reply”). With our
authorization, Petitioner filed a Supplemental Opposition to Patent Owner’s
Non-Contingent Motion to Amend. Paper 36 (“Pet. Supp. Opp.”). Patent
Owner filed a Response to Petitioner’s Supplemental Opposition. Paper 39
(“PO Resp. to Supp. Opp.”). Petitioner filed a Sur-Reply to Patent Owner’s
Reply in support of the Non-Contingent Motion to Amend. Paper 40 (“Pet.
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Sur-Reply”). An oral hearing was held on May 18, 2021. A transcript of the
hearing is included in the record. Paper 49 (“Tr.”). Subsequent to the
hearing, Patent Owner filed, with our authorization, a Revised Non-
Contingent Motion to Amend. Paper 47 (“Rev. Mot. to Amend.”).
Petitioner filed a response to Patent Owner’s Revised Non-Contingent
Motion to Amend. Paper 48 (“Pet. Resp. to Rev. Mot. to Amend.”).
B. Related Proceedings
According to the parties, the ’298 patent is the subject of the
following action: Impinj, Inc. v. NXP USA, Inc., No. 4:19-cv-03161-YGR
(N.D. Cal.) filed June 6, 2019. Pet. 62; Paper 5, 2–3. The parties
acknowledge that Petitioner has filed another petition (IPR2020-00552)
challenging the ’298 patent. Paper 5, 3; see Pet. 62. The parties also
identify IPR petitions Petitioner has filed against other family members of
the ’298 patent. Paper 5, 3–4; Pet. 62. The following table identifies these
inter partes review case numbers and their respective patent numbers:
Case No. U.S. Patent No.
IPR2020-00514 9,471,816 (“the ’816 patent”)
IPR2020-00516 9,633,302 (“the ’302 patent”)
IPR2020-00519 8,115,597 (“the ’597 patent”)
IPR2020-00543 9,495,631 (“the ’631 patent”)
IPR2020-00544 8,344,857 (“the ’857 patent”)
IPR2020-00552 8,600,298 (“the ’298 patent”)
IPR2020-00554 9,031,504 (“the ’504 patent”)
IPR2020-00556 the ’504 patent
IPR2020-00589 10,002,266 (“the ’266 patent”)
See Paper 5, 3–4.
C. The ’298 Patent (Ex. 1001)
The ’298 patent relates to Radio Frequency Identification (“RFID”)
systems that use an RFID reader to interrogate an RFID tag attached to an
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object. Ex. 1001, 1:19–22, 1:29–30. In an RFID system, an RFID reader
may transmit an interrogating RF wave. Id. at 1:29–31, 4:39–41, Fig. 1. A
RFID tag in the vicinity may sense the RF wave and respond by transmitting
back another RF wave that the RFID reader may then sense and interpret.
Id. at 1:31–33, 4:41–44, Fig. 1. The ’298 patent recognizes, however, that
an interrogating RF wave may experience distortion due to interference
caused by, for example, other RF signals sent from nearby mobile devices.
Id. at 1:54–61. As a result, when the RFID tag circuit converts the received
RF wave into a received signal, that signal may also be distorted. Id. at
1:62–64. “The distorted signal may cause false bits to be detected by the
RFID tag, which in turn can result in the RFID tag not being able to detect
the interrogating RF wave reliably, or parse its commands.” Id. at 1:64–67.
For example, the RFID tag circuit may include a demodulator that receives
the distorted RF input signal and converts it to a digital output signal that
also includes distortion. Id. at 8:18–23, Fig. 7 (item 742). Due to the
distortion, the digital output signal may include an artifact feature that is
received and interpreted by a processor such that the processor may not
respond exactly as intended. Id. at 8:28–33, Fig. 7 (item 744).
To address this problem, the ’298 patent describes an interference
rejection filtering circuit (“IRF”) for filtering a received RF signal to remove
any artifact features from the signal and generating a filtered output that
does not include artifact features. Id. at 1:12–14, 10:14, 10:16–20. Figure 9
of the ’298 patent is reproduced below.
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Figure 9, shown above, depicts a partial block diagram of an RFID tag
circuit including first circuit (e.g., demodulator) 942, IRF 968 with filter
portion 969, and processor 944 for generating filtered output 972 from
unfiltered input 971. Id. at 9:54–57. Filter portion 969 may identify features
of unfiltered input 971 and apply them to a first criterion related to time
duration to determine whether the feature is an artifact arising from a
distortion due to interference. Id. at 10:43–47, 11:6–10. Features that meet
the first criterion may be detected as artifact features and may be removed
from filtered output 972, whereas features that do not meet the first criterion
may be deemed legitimate and included in filtered output 972. Id. at 10:45–
51.
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Figure 12A of the ’298 patent is reproduced below.

Figure 12A, shown above, depicts how unfiltered digital signal input
1210 can be rendered over time. Id. at 12:24–25. Signal 1210 is digital—
meaning that it has two extreme values (high and low) as well as transitions
between them. Id. at 12:26–27. In signal 1210, low going pulses 1212,
1214, and 1216 can be identified by their respective transitions from high-to-
low and then low-to-high. Id. at 12:40–41. According to the figure, pulses
1212 and 1216 are deemed long enough and, thus, are retained, whereas
pulse 1214 is deemed too short and, thus, is detected as an artifact and
rejected. Id. at 12:41–44.
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Figure 12B of the ’298 patent is reproduced below.

Figure 12B, shown above, depicts a filtered output generated as signal
1260 from the unfiltered input of Figure 12A. Id. at 12:48–49. As noted by
comment 1264, in Figure 12B there is no pulse corresponding to pulse 1214
of signal 1260 because the artifact feature associated with that pulse has
been rejected. Id. at 12:55–58.
According to the ’298 patent, filter characteristics may be fixed or
adjustable. See, e.g., id. at 10:53–55. For example, time duration threshold
may be adjusted based on information associated with an RF input signal,
such as a preamble, a received packet, a filtered output signal, a data rate, or
an expected next packet. See, e.g., id. at 14:60–61, 15:15–27, 16:60–61,
17:13–18, 17:37–44, 18:13–14, 18:39–44, Figs. 15, 20, 22, 23B.
D. Cancelled Claims 1–5, 8–12, and 15–19
Our rules provide for cancellation of challenged claims. See 37
C.F.R. § 42.121(a)(3) (“A motion to amend may cancel a challenged
claim”). Patent Owner’s Non-Contingent Motion to Amend requests
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cancellation of all the challenged claims, 1–5, 8–12, and 15–19.1 Paper 24,
4; Paper 48, 4. Patent Owner’s counsel confirmed at the oral hearing that it
intended to cancel all of the challenged claims. Paper 49, 5:19–6:9. Patent
Owner’s request to cancel challenged claims 1–5, 8–12, and 15–19 of the
’298 patent is granted.
E. Proposed Substitute Claims 22–36
Proposed substitute claims 22, 27, and 32 are independent, with
proposed substitute claims 23–26 depending from claim 22, proposed
substitute claims 28–31 depending from claim 27, and proposed substitute
claims 33–36 depending from claim 32. Proposed substitute claims 22 and
32 recite a Radio Frequency Identification (RFID) tag circuit, and proposed
substitute claim 27 recites a method for a Radio Frequency Identification
(RFID) tag circuit. Claim 22 is proposed as a substitute for cancelled claim
1 and is set out below, showing added language underlined and deleted
language struck out in comparison to cancelled claim 1.
[22-pre] A Radio Frequency Identification (RFID) tag circuit
comprising:
[22-a] a demodulator configured to: receive a modulated wireless
RF input signal form an RFID reader, and derive a first digital
output signal responsive to the modulated wireless RF input
signal, wherein the first digital output signal comprises a
sequence of digital pulses; and
[22-b] an interference rejection circuit configured to: receive the
first digital output signal, and filter the first digital output signal

1 In a non-contingent motion to amend, “the Board provides a final decision
on the patentability of substitute claims in place of determining the
patentability of corresponding original claims.” Notice Regarding a New
Pilot Program Concerning Motion To Amend Practice and Procedures in
Trial Proceedings Under the America Invents Act Before the Patent Trial
and Appeal Board, 84 Fed. Reg. 9497, 9505 (Mar. 15, 2019).
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to determine a first time duration threshold, derive a second
digital output signal, by: setting a filter pass range to detect a
delimiter, detecting the delimiter,
[22-c] detecting an expected next packet after the delimiter, and
[22-d] based on an aspect of the expected next packet, adjusting
the filter pass range for detecting a command, wherein the
interference rejection circuit is configured to retain digital pulses
within the pass range and remove digital pulses shorter than the
pass range. responsive to the first digital output signal by
substantially retaining digital pulses longer than the first time
duration threshold, and adjust the first time duration threshold
based on at least one aspect associated with the wireless RF input
signal selected from a preamble, a received packet, a filtered
output signal, a data rate, and an expected next packet.
Paper 24, App. A (bracketed designations added).
F. Evidence
Petitioner relies upon the following evidence to challenge the
patentability of the proposed substitute claims:
(1) U.S. Patent Application Publication No. US 2006/0244598 A1,
published November 2, 2006 (“Hyde ’598”) (Ex. 1005);
(2) U.S. Patent Application Publication No. US 2002/0152044 A1,
published October 17, 2002 (“Shanks”) (Ex. 1006);
(3) U.S. Patent No. 3,997,798, issued December 14, 1976
(“Breimesser”) (Ex. 1007);
(4) U.S. Patent No. 4,779,077, issued October 18, 1988 (“Lichtblau”)
(Ex. 1008);
(5) EPC™ Radio-Frequency Identity Protocols Class-1 Generation-2
UHF RFID Protocol for Communications at 860 Mhz – 960 Mhz Version
1.0.9, EPCglobal, Inc. (January 2005) (“Gen2”) (Ex. 1015);
(6) First Declaration of Dr. Travis Blalock, February 10, 2020
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(Ex. 1003); and
(7) Second Declaration of Dr. Travis Blalock, February 2, 2021
(Ex. 1020).
Patent Owner relies upon the following evidence in support of the
patentability of the proposed substitute claims:
(1) First Declaration of Dr. James Kenney, May 20, 2020
(Ex. 2001); and
(2) Second Declaration of Dr. James Kenney, March 16, 2021
(Ex. 2009).
G. Asserted Grounds of Unpatentability
Petitioner challenges the patentability of the proposed substitute
claims on the following grounds:
Claims Challenged 35 U.S.C. § References
22–36 103(a) Shanks, Breimesser, Lichtblau,
Gen2
22–36 102(b) Hyde ’5982

2 In its Supplemental Opposition to Patent Owner’s Non-Contingent Motion
to Amend, Petitioner alleges Hyde ’598 anticipates substitute claims 22–36
because “Patent Owner relies on the ’177 Application, which published as
Hyde ’598, for its disclosure of the subject matter it seeks to claim” and
Hyde ’598 “is prior art to the ’298 [patent].” Paper 36, 4; see also id. at 1–4.
Hyde ’598 was part of the subject matter of a certificate of correction sought
by Patent Owner for the ’298 patent. See Paper 39, 1–2. Patent Owner asks
us to use our “discretion in not considering the new Hyde ’598 ground in the
instant trial.” Id. at 1. As explained below, we need not reach the asserted
ground based on Hyde ’598.
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ANALYSIS
A. Principles of Law
In an inter partes review, amended claims are not added to a patent as
of right, but rather must be proposed as a part of a motion to amend.
35 U.S.C. § 316(d) (2018). The Board must assess the patentability of
proposed substitute claims “without placing the burden of persuasion on the
patent owner.” Aqua Prods., Inc. v. Matal, 872 F.3d 1290, 1328 (Fed. Cir.
2017) (en banc); see also Lectrosonics, Inc. v. Zaxcom, Inc., IPR2018-
001129, Paper 15 at 3–4 (PTAB Feb. 25, 2019) (precedential). Subsequent
to the issuance of Aqua Products, the Federal Circuit issued a decision in
Bosch Automotive Service Solutions, LLC v. Matal, 878 F.3d 1027 (Fed. Cir.
2017) (“Bosch”), as well as a follow-up Order amending that decision on
rehearing. See Bosch Auto. Serv. Sols., LLC v. Iancu, No. 2015-1928 (Fed.
Cir. Mar. 15, 2018) (Order on Petition for Panel Rehearing).
In accordance with Aqua Products, Bosch, and Lectrosonics, a patent
owner does not bear the burden of persuasion to demonstrate the
patentability of the substitute claims presented in the motion to amend.
Rather, ordinarily, “the petitioner bears the burden of proving that the
proposed amended claims are unpatentable by a preponderance of the
evidence.” Bosch, 878 F.3d at 1040 (as amended on rehearing); see
Lectrosonics, Paper 15 at 3–4. In determining whether a petitioner has
proven unpatentability of the substitute claims, the Board focuses on
“arguments and theories raised by the petitioner in its petition or opposition
to the motion to amend.” Nike, Inc. v. Adidas AG, 955 F.3d 45, 51 (Fed. Cir.
2020).
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Patent Owner’s proposed substitute claims, however, must meet the
statutory requirements of 35 U.S.C. § 316(d) and the procedural
requirements of 37 C.F.R. § 42.121. Lectrosonics, Paper 15 at 4–8.
Accordingly, Patent Owner must demonstrate: (1) the amendment proposes
a reasonable number of substitute claims; (2) the proposed claims are
supported in the original disclosure (and any earlier filed disclosure for
which the benefit of filing date is sought); (3) the amendment responds to a
ground of unpatentability involved in the trial; and (4) the amendment does
not seek to enlarge the scope of the claims of the patent or introduce new
subject matter. See 35 U.S.C. § 316(d); 37 C.F.R. § 42.121.
A proposed substitute claim, however, is unpatentable under
35 U.S.C. § 102 if the claimed invention is anticipated by a disclosure that is
available as prior art. “A claim is anticipated when ‘the four corners of a
single, prior art document describe every element of the claimed invention,
either expressly or inherently, such that a person of ordinary skill in the art
could practice the invention without undue experimentation.’” Spansion,
Inc. v. Int’l Trade Comm’n, 629 F.3d 1331, 1356 (Fed. Cir. 2010) (quoting
Advanced Display Sys., Inc. v. Kent State Univ., 212 F.3d 1272, 1282 (Fed.
Cir. 2000)). The elements must be arranged as required by the claim, but
this is not an ipsissimis verbis test, i.e., identity of terminology is not
required. In re Bond, 910 F.2d 831, 832 (Fed. Cir. 1990).
A proposed substitute claim may also be unpatentable under 35
U.S.C. § 103 if “the differences between the subject matter sought to be
patented and the prior art are such that the subject matter as a whole would
have been obvious at the time the invention was made to a person having
ordinary skill in the art to which said subject matter pertains.” KSR Int’l Co.
v. Teleflex Inc., 550 U.S. 398, 406 (2007). The question of obviousness is
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resolved on the basis of underlying factual determinations, including:
(1) the scope and content of the prior art; (2) any differences between the
claimed subject matter and the prior art; (3) the level of skill in the art; and,
where presented, (4) objective evidence of nonobviousness, i.e., secondary
considerations. See Graham v. John Deere Co. of Kansas City, 383 U.S. 1,
17–18 (1966).
The Supreme Court has made clear that we apply “an expansive and
flexible approach” to the question of obviousness. KSR, 550 U.S. at 415.
Whether a patent claiming the combination of prior art elements would have
been obvious is determined by whether the improvement is more than the
predictable use of prior art elements according to their established functions.
Id. at 417. Reaching this conclusion, however, requires more than a mere
showing that the prior art includes separate references covering each
separate limitation in a claim under examination. Unigene Labs., Inc. v.
Apotex, Inc., 655 F.3d 1352, 1360 (Fed. Cir. 2011). Rather, obviousness
requires the additional showing that a person of ordinary skill at the time of
the invention would have selected and combined those prior art elements in
the normal course of research and development to yield the claimed
invention. Id.
B. Level of Ordinary Skill
We review the grounds of unpatentability in view of the
understanding of a person of ordinary skill in the art at the time of the
invention. Graham, 383 U.S. at 17. In the Institution Decision, we
generally adopted Petitioner’s assessment of a person of ordinary skill in the
art, as a person having a bachelor’s degree in electrical engineering or
computer engineering and two years of experience in the field of integrated
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circuit design or an equivalent combination of education, work, and/or
experience. Paper 15, 8–9 (citing Pet. 11). In its Motion to Amend, Patent
Owner accepts our assessment of a person of ordinary skill in the art for
purposes of this proceeding. Paper 24, 19. We continue to apply that
assessment here.
C. Claim Construction
In this proceeding, a claim shall be construed using the same claim
construction standard that would be used to construe the claim in a civil
action under 35 U.S.C. § 282(b), including construing the claim in
accordance with the ordinary and customary meaning of such claim as
understood by one of ordinary skill in the art and the prosecution history
pertaining to the patent. 37 C.F.R. § 42.100 (2019). We therefore apply the
claim construction standard as set forth in Phillips v. AWH Corp., 415 F.3d
1303 (Fed. Cir. 2005) (en banc).
Under Phillips, claim terms are generally given their ordinary and
customary meaning as would have been understood by one with ordinary
skill in the art in the context of the specification, the prosecution history,
other claims, and even extrinsic evidence including expert and inventor
testimony, dictionaries, and learned treatises, although extrinsic evidence is
less significant than the intrinsic record. Phillips, 415 F.3d at 1312–17.
Usually, the specification is dispositive, and it is the single best guide to the
meaning of a disputed term. Id. at 1315.
Only terms that are in controversy need to be construed, and then only
to the extent necessary to resolve the controversy. Nidec Motor Corp. v.
Zhongshan Broad Ocean Motor Co. Matal, 868 F.3d 1013, 1017 (Fed. Cir.
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2017) (in the context of an inter partes review, applying Vivid Techs., Inc. v.
Am. Sci. & Eng’g, Inc., 200 F.3d 795, 803 (Fed. Cir. 1999)).
In the Institution Decision, we determined that no claim term required
express construction at that stage of the proceeding. Paper 15, 9–17. In its
Motion to Amend, Patent Owner stated that it “does not believe that any of
the limitations added to the substitute claims require construction and should
instead be construed in accordance with their ordinary meaning.” Paper 24,
19. In its Opposition to the Motion to Amend, Petitioner does not propose
any express claim construction. To the extent that the determination of the
meaning of any claim term is necessary, we use its ordinary and customary
meaning.
D. Statutory and Regulatory Requirements
As noted above, Patent Owner’s proposed substitute claims must meet
the statutory requirements of 35 U.S.C. § 316(d) and the procedural
requirements of 37 C.F.R. § 42.121. We address each of these requirements
in turn.
1. Reasonable Number of Substitute Claims
A motion to amend must “propose a reasonable number of substitute
claims.” 35 U.S.C. § 316(d)(1)(B); see 37 C.F.R. § 42.121(a)(3) (“A motion
to amend may cancel a challenged claim or propose a reasonable number of
substitute claims.”). Patent Owner proposes the same number of substitute
claims as the original challenged claims that are cancelled, i.e. a one-to-one
substitution for a total of fifteen substitute claims. Paper 24, 4–5. “There is
a rebuttable presumption that a reasonable number of substitute claims per
challenged claim is one (1) substitute claim.” Lectrosonics, Paper 15 at 4;
see 37 C.F.R. § 42.121(a)(3). Petitioner does not argue otherwise. See
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generally Paper 28. Therefore, we determine that Patent Owner proposes a
reasonable number of substitute claims.
2. Support in the Original Disclosure
A motion to amend may not present substitute claims that introduce
new subject matter. 35 U.S.C. § 316(d); 37 C.F.R. § 41.121(a)(2)(ii). New
matter is any addition to the claims without support in the original
disclosure. See TurboCare Div. of Demag Delaval Turbomach. v. Gen.
Elec. Co., 264 F.3d 1111, 1118 (Fed. Cir. 2001) (“When [an] applicant adds
a claim . . . the new claim[] . . . must find support in the original
specification.”); see also Lectrosonics, Paper 15 at 7 (“the Board requires
that a motion to amend set forth written description support in the originally
filed disclosure of the subject patent for each proposed substitute claim”).
As noted, supra, subsequent to the hearing, Patent Owner filed, with
our authorization, a Revised Non-Contingent Motion to Amend. Paper 47.
The purpose of this filing was to allow Patent Owner the opportunity to
revise its Motion to Amend to provide citation support to the originally filed
disclosure for the ’298 patent, which Patent Owner asserts was left out of the
original motion because of its good-faith reliance on an inadvertently issued
certificate of correction. See Paper 46, 3–5; Paper 47, 7–19. In its Response
to Patent Owner’s Revised Motion, Petitioner states that it “does not oppose
Patent Owner’s revised Motion to Amend to provide citations to Application
No. 13/666,285 for its argument that the proposed substitute claims are
supported by the written description.” Paper 48, 1 (citing Paper 47, 7 n.2).
Patent Owner has identified written description support in the
originally filed disclosure of the ’298 patent for the new limitations added
for the proposed substitute claims. See Paper 47, 7–19. We have reviewed
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Patent Owner’s assertions of support in the original disclosure for the
proposed substitute claims and determine that sufficient support exists.
3. Respond to a Ground of Unpatentability
“A motion to amend may be denied where . . . [t]he amendment does
not respond to a ground of unpatentability involved in the trial.” 37 C.F.R.
§ 42.121(a)(2)(i). Patent Owner asserts that the proposed substitute claims
are patentable over the combination of references that forms the basis of the
obviousness ground on which we instituted trial. Paper 24, 15. In particular,
Patent Owner asserts that “the amended claims recite a manner of filtering
the signal using an adjustable filter that operates in a manner not disclosed in
the filtering circuits disclosed in the prior art of record.” Id. Petitioner does
not argue otherwise. See generally Paper 28. We determine that the
amended language in the proposed substitute claims is responsive to a
ground of unpatentability involved in this trial.
4. Scope of the Claims
Patent Owner asserts that the substitute claims are each narrower than
the corresponding original claim. Paper 24, 16. “For example,” Patent
Owner argues, “substitute claim 22 is narrower than corresponding original
claim 1 because it recites circuitry that filters the digital pulses in a more
specific way.” Id. “Specifically,” Patent Owner argues,
claim 22 first recites setting a filter pass range, where a filter will
remove pulses shorter than the pass range yet retain pulses within
the pass range, similar to how the interference rejection circuit in
original claim 1 removes pulses shorter than a first-time duration
threshold yet retains pulses longer than the first-time duration
threshold.
Id.
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“Claim 22 narrows original claim 1,” Patent Owner argues, “by
requiring that this filter pass range to be specifically set to detect a delimiter
(i.e., a signal of a boundary), which is not required by original claim 1.” Id.
“Claim 22 also narrows original claim 1,” Patent Owner argues, “by
requiring detection (and use of an aspect) of an expected next packet, versus
original claim 1’s broader recitation of one of ‘a preamble, a received
packet, a filtered output signal, a data rate, and an expected next packet.’”
Id. “Claim 22 further narrows original claim 1,” Patent Owner argues, “by
requiring adjustment of the filter pass range for detecting a command,
whereas original claim 1 did not specify the rationale for adjusting the first
time duration threshold.” Id. “Thus,” Patent Owner argues, “substitute
claim 22 recites a narrower, more specific way of removing and retaining
digital pulses than original claim 1.” Id.
Patent Owner makes similar arguments with respect to the other
proposed substitute claims. See id. at 16–19.
Petitioner, however, asserts that the proposed substitute claims are
impermissibly broader. See Paper 28, 2–3. Petitioner argues that the
proposed claims are broader in scope because, for example, “a device
configured for ‘setting a filter pass range’ and ‘adjusting the filter pass
range’ would not have infringed claim 1, but would now potentially infringe
proposed substitute claim 22 because ‘determin[ing] a first time duration
threshold’ is not a limitation.” Id. at 3 (alteration in original).
Because we determine that the proposed substitute claims would have
been obvious over the combined teachings of the prior art (see Section II.F
infra), we need not determine whether a device configured for “setting a
filter pass range” and “adjusting the filter pass range” could potentially
infringe proposed substitute claim 22, but not original claim 1, as Petitioner
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argues here. Cf. Boston Sci. Scimed, Inc. v. Cook Grp. Inc., 809 F. App'x
984, 990 (Fed. Cir. Apr. 30, 2020) (non-precedential) (recognizing that the
“Board need not address issues that are not necessary to the resolution of the
proceeding” and, thus, agreeing that the Board has “discretion to decline to
decide additional instituted grounds once the petitioner has prevailed on all
its challenged claims”).
Accordingly, we decline to determine whether the amendment seeks
to enlarge the scope of the claims of the patent.
E. Relevant Prior Art
1. Shanks (Ex. 1006)
Shanks is a U.S. Patent Application Publication that published on
October 17, 2002, more than one year before the earliest priority date of the
’298 patent. Ex. 1001, code (63); Ex. 1006, code (43). Petitioner asserts
that Shanks is prior art under pre-AIA 35 U.S.C. § 102(a), (b), and (e). Pet.
13.
Shanks relates to an RFID architecture including readers for
interrogating and powering tags at data rates, distances, and reliability levels
greater than existing readers. Ex. 1006 ¶ 9.
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Figure 10 of Shanks is reproduced below.

Figure 10, shown above, depicts a block diagram of an RFID tag
according to an embodiment of Shanks. Id. ¶¶ 25, 124. Tag 1002, which is
printed on substrate 1001, includes integrated circuit 1002, a data
programming unit 1020, state machine 1024, timing subsystem 1023, and
RF interface portion 1021. Id. ¶ 142. RF interface portion 1021 “includes
components that . . . demodulate RF signals into digital information
symbols.” Id. ¶ 144.
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Figure 30 of Shanks is reproduced below.

Figure 30, shown above, depicts analog front-end 3000 of an
exemplary RF tag. Id. ¶ 526. Analog front-end 3000 includes data recovery
circuit 3010, which demodulates RF signal 3003 and generates a digital
output signal labeled “DMOD” at output terminal 3012. Id. ¶ 527.
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Figure 42 of Shanks is reproduced below.

Figure 42, shown above, depicts an exemplary data recovery circuit
4200 that is an embodiment of data recovery circuit 3010 of Figure 30. Id.
¶ 562. Data recovery circuit 4200 may include a fast charge pump 4202 to
demodulate RF signal 3003 and a comparator 4216 to further process the
demodulated output signal 4203 to generate digital output signal 4220. Id.
¶¶ 562–63.
In one embodiment of Shanks, the tag may receive, from a reader
network, a modulated wireless RF input signal that conveys information in
the form of one or more symbols for a particular duration of time. Id. ¶¶ 73,
74, 95, 96, 150. Figures 3, 4, and 5 of Shanks are reproduced below.
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Figure 3, above, shows that, when transmitting a symbol that
represents a logical “0”, the reader network maintains its carrier signal
amplitude at Slow for a duration of TA = 3 microseconds. Id. ¶¶ 96, 99.

Figure 4, above, shows that, when transmitting a symbol that
represents a logical “1”, the reader network maintains its carrier signal
amplitude at Slow for a duration of TA = 6 microseconds. Id.
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Figure 5, above, shows that, when transmitting a symbol that
represents a logical “NULL” symbol, the reader network maintains its
carrier signal amplitude at Slow for a duration of TA = 9.5 microseconds. Id.
As shown in Figures 3 through 5, the reader network may transmit one
symbol every 12.5 microseconds, which represents a “symbol exchange
period.” Id. ¶ 97.
The duration of timing intervals that define these symbols may be set
during a calibration routine in which the reader network transmits a series of
pulse waveforms received by a tag. Id. ¶¶ 475, 477–78. The tag may use
the received pulse waveforms to set boundaries for the timing intervals that
define the symbols. Id. ¶ 475. The duration of a received calibration
waveform may be measured as the duration of time passing between the
falling edge and rising edge of its pulse. Id. ¶ 478.
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Figure 26A is reproduced below.

Figure 26A, above, shows calibration waveforms for three time
periods: 2602 (the time between TCS and TTO, e.g., 4.5 milliseconds), 2604
(the time between TCS and TT1, e.g., 7.75 milliseconds), and 2606 (the time
between TCS and TT2, e.g., 11.5 milliseconds). Id. ¶¶ 478–80. Figure 26B is
reproduced below.

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Figure 26B, above, shows that if the trailing rising edge of a data
symbol pulse occurs between time TCS and TT0, the data symbol will be
interpreted as a logical “0” value; if the trailing rising edge occurs between
time TT0 and TT1, the data symbol will be interpreted as a logical “1”; and if
the trailing rising edge occurs between time TT1 and TT2, the data symbol
will be interpreted as a logical “NULL” value. Id. ¶¶ 479–480. TT2 may be
set to a longer time period to allow the reader network to decrease
transmitted data rates such that noise immunity may be improved.
2. Breimesser (Ex. 1007)
Breimesser is a U.S. Patent that issued on December 14, 1976, more
than one year before the earliest priority date of the ’298 patent. Ex. 1001,
code (63); Ex. 1007, code (45). Petitioner asserts that Breimesser is prior art
under pre-AIA 35 U.S.C. § 102(a), (b), and (e). Pet. 13.
Breimesser relates to a circuit arrangement for gating out pulses and
pulse gaps whose duration is shorter than a given test period. Ex. 1007, 1:9–
12.
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Figure 1 of Breimesser is reproduced below.

Figure 1, above, shows a circuit arrangement for gating out pulses
according to an embodiment of Breimesser. Id. at 4:52–53. “If pulse gaps
are to be gated out it is also possible to use this circuit arrangement if the
input signal is inverted” by “preced[ing] the gate 1 by an inverter whose
output is connected to the first input 5.” Id. at 4:53–57; see also id. at 5:62–
6:16, Fig. 3. According to Figure 1, output 7 of gate 1 is connected to
counter input 8 of counter 2. Id. at 3:3–4. From counter 2, parallel outputs
12 and 14 are connected to inputs 15 and 17 of decoder 3. Id. at 3:4–6.
Output 18 of decoder 3 is connected to first input 19 of binary storage circuit
4. Id. at 3:6–8. First input 5 of gate 1 is connected to setting input 21 of
counter 2 and to second input 20 of the binary storage circuit 4. Id. at 3:8–
10.
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Figure 2 of Breimesser is reproduced below.

Figure 2 of Breimesser, above, shows a mode of operation of the
circuit arrangement shown above in Figure 1 of Breimesser.
“The digital pulse sequence I is fed to the first input 5 of the gate 1,”
which may be an AND gate or a NAND gate. Id. at 3:15–16, 3:26–28. “A
counter pulse sequence II is connected to the second input 6 of the gate,”
with a pulse train length of counter pulses assumed to be tt. Id. at 3:21–23.
Output Q inverse of the binary storage element 4 is connected to the third
input 22 of gate 1. Id. at 4:67–5:1
“The gate 1 in the circuit . . . is only open for the counter pulses when
and for as long as an input pulse is present at the input 5.” Id. at 3:23–27.
“If then an input pulse appears at the input 5 of the gate, . . . the pulse
sequence III composed of individual groups of counter pulses appears at the
output 7 of the gate.” Id. at 3:28–31. “These counter pulses pass to the
counter input 8 and the counter 2,” which counts the counter pulses “from a
given initial value m with the first pulse of each pulse group, and continues
to count for the maximum until the pulse at the input 5 is at an end.” Id. at
3:35–41. “The decoder 3 establishe[s] the individual states of the counter
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and when a predetermined value n is reached in the counter, it emits a pulse
at the output 18. Id. at 3:46–49. “The pulses E and F of the pulse sequence
IV represent the pulses from the output of the decoder.” Id. at 3:51–53.
“[P]ulses only appear at the output 18 of the decoder if the input pulse is
longer than the test period tp.” Id. at 3:55–58.
The pulse from the output 18 of the decoder sets the output Q of
the binary storage element via the input 19 to l. This state
continues until the storage element is reset via the input 20. . . .
[T]he output pulse sequence V with the pulses G and H arises at
the output Q of the storage element. As will be seen from this
sequence, pulses occur only if the input pulse is longer than the
test period tp. The front edges of the pulses G and H are
displaced by the time tp + td and shortened in comparison to the
input pulses A and D in the sequence I.
Id. at 3:63–4:7.
The values m and n, and the pulse train length tt of the counter pulses
determine the test period tp in accordance with tp = (m – n) ∙ tt.” Id. at 3:46–
51. “The test period may be freely programmed and can be varied within
wide limits.” Id. at 2:40–41. “In FIG. 2, tp = 4 ∙ tt was selected by way of
example.” Id. at 3:53–54.
“The above described circuit arrangements can be used for gating out
interference signals of shorter duration than the useful signal.” Id. at 7:47–
49.
3. Lichtblau (Ex. 1008)
Lichtblau is a U.S. Patent that issued on October 18, 1988, more than
one year before the earliest priority date of the ’298 patent. Ex. 1001, code
(63); Ex. 1008, code (45). Petitioner asserts that Lichtblau is prior art under
pre-AIA 35 U.S.C. § 102(a), (b), and (e). Pet. 13.

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Lichtblau “is directed to the field of noise rejection circuitry, and
more particularly, to a continuously armed, highly reliable, pulse train
processor especially for magnetic strip and resonant tag signal detection.”
Ex. 1008, 1:6–10. Figure 1 of Lichtblau is reproduced below.

Figure 1, above, shows a continuously armed, high reliability pulse
train processor in an exemplary magnetic and resonant interrogation system
receiver application according to one embodiment. Id. at 2:34–38.
Lichtblau describes a circuit whose antenna 15 receives a “radio frequency
signal” that is “demodulated by the receiver 16, filtered in a band-pass filter
20 to remove noise, and amplified in an amplifier 22. Thereafter the signal
is fed in parallel into the pulse train processor 24.” Id. at 2:56–3:4. The
pulse train processer may include three pulse processing modules, each of
which includes a “minimum and maximum pulse width detector pair[] . . .
selected to conform to the expected duration time . . . of the corresponding
. . . pulses of the expected pulse train.” Id. at 4:34–36, 4:65–5:–6, Fig. 2.
“Only the correct polarity sequence of pulses above a preselected threshold
that exist within carefully defined time durational windows are passed
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through by the pulse train processor, while all other pulse signals kinds and
types are rejected thereby as undesirable noise.” Id. at 5:6–11. Thus,
Lichtblau describes “a pulse train processor that is responsive to both the
minimum duration and to the maximum duration of each of the several
pulses.” Id. at 2:3–9.
4. Gen2 (Ex. 1015)3
The article, EPC™ Radio-Frequency Identity Protocols Class-1
Generation-2 UHF RFID Protocol for Communications at 860 MHz – 960
MHz Version 1.0.9, published by EPC Global, Inc., is a specification for
RFID air interface. The specification defines the base class (Class-1) of four
RFID Tag classes. Ex. 1015, App. A, 8. The Gen2 system comprises
“Interrogators, also known as Readers, and Tags.” Id. at 1, 9. “An
Interrogator transmits information to a Tag by modulating an RF signal.” Id.
at 9. The information is pulse-interval encoded (PIE), whereby pulses of
energy are transmitted for different intervals of time (i.e., symbols) to
communicate information that is interpreted by the tag as either a binary 0 or
a binary 1. Ex. 1020 ¶ 351.
In Gen2, the duration (pulse-interval) of the encoded symbols is
specified by a “Tari” reference time interval where 1 Tari is equivalent to the
duration of a data-0 symbol. Ex. 1015, § 6.3.1.2.3, Fig. 6.1; see Ex. 1020
¶ 355. Data-1 symbols are transmitted using pulses between 1.5 to 2.0 Tari.

3 Exhibit 1015 includes an Affidavit of Elizabeth Rosenberg, averring to
certain facts Petitioner uses to establish the public availability of the Gen2
reference as prior art to the ’298 patent. See Ex. 1015, 1–2; Paper 28, 3–4.
Patent Owner does not challenge the public availability of Gen 2, or its
status as prior art to the ’298 patent. See Paper 49, 31:1–11. Based on the
evidence of record, we determine that Petitioner has established the public
availability of the Gen2 reference as prior art to the ’298 patent.
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Id. Tari values of 6.25μs, 12.5μs, or 25μs are preferred for reader to tag
(“R=>T”) communications. Id. at Tables 6.5, 6.6.
Gen 2 specifies an “inventory” process that is used for identifying
tags. Ex. 1015, § 6.3.2.6; Ex. 1020 ¶ 356. To initiate the R=>T signaling
for “an inventory round,” readers transmit a “preamble or a framesync.”
Ex. 1015, § 6.3.1.2.8, Fig. 6.4. Both the preamble and the frame-sync
include a fixed-length start delimiter, a data-0 symbol, and an R=>T
calibration (RTcal) symbol. Id. The data-0 symbol that follows the
delimiter is used to specify the length of a data-0 symbol for the R=>T
communications. Id. The RTcal symbol specifies the combined length of a
data-0 symbol and a data-1 symbol. Id. A tag interprets subsequent symbols
that are shorter than duration of RTcal / 2 as data-0 symbols, and symbols
longer than RTcal / 2 as data-1 symbols, except that symbols longer than
four times RTcal are “bad data.” Id.; Ex. 1020 ¶ 356.
F. Obviousness Based on Shanks, Breimesser, Lichtblau, and Gen2
Petitioner asserts proposed substitute claims 22–36 are unpatentable
as obvious under 35 U.S.C. § 103 over the combined teachings of Shanks,
Breimesser, Lichtblau, and Gen2. See Paper 28, 7–24. The parties
principally rely on their arguments directed to independent claim 22. See
Paper 28, 22; Paper 30, 1. We address any arguments specifically directed
to independent claims 27 and 32 separately.
1. Proposed Substitute Independent Claim 22
[22-pre] A Radio Frequency Identification (RFID) tag
circuit comprising:
Proposed substitute Claim 22 recites the same preamble as claim 1.
Paper 24, App. A; Ex. 1001, 21:37–38. Petitioner asserts that Shanks
teaches an RFID tag circuit. Paper 28, 7 (citing Pet. 24; Ex. 1020 ¶ 361).
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Petitioner argues that “Shanks discloses an RFID tag circuit in Figure 10”
and “[a]s shown in FIG. 10, integrated circuit 1002 includes a data
programming unit 1020, a state machine 1024, a timing subsystem 1023, and
an RF interface portion 1021.” Pet. 24 (citing Ex. 1006 ¶¶ 3, 25, 142;
Ex. 1003 ¶ 158).
Figure 10 of Shanks is shown below.

Shanks Figure 10, shown above, depicts a block diagram of an RF tag.
Ex. 1006 ¶ 124; Fig. 10.
Patent Owner does not contest Petitioner’s evidence that Shanks
teaches a RFID tag circuit. See Paper 30, 1–12. Petitioner’s arguments are
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supported by the cited evidence. Based on the evidence of record, we are
persuaded that Petitioner has demonstrated that Shanks teaches a “Radio
Frequency Identification (RFID) tag circuit” as recited in the preamble of
proposed substitute claim 22.
[22-a] a demodulator configured to: receive a modulated
wireless RF input signal from an RFID reader, and
derive a first digital output signal responsive to the
modulated wireless RF input signal, wherein the first
digital output signal comprises a sequence of digital
pulses
Petitioner asserts that Shanks teaches this limitation because “Shanks
discloses demodulating an RF input signal that is received from an RF
reader, and deriving a first digital output signal comprising a sequence of
digital pulses.” Paper 28, 7 (citing Pet. § VI.A.1(b) (claim [1-a]); Ex. 1020
¶ 362). Petitioner also argues that “[t]his limitation is also disclosed by
Figure 7 of the ’177 Application, which the applicant admitted was prior
art.” Paper 28, 7 (citing Ex. 1010, 11).
Petitioner argues that “Gen2 also discloses tags that ‘receive a
modulated wireless RF input signal from an RFID reader.’” Paper 28, 7
(citing Ex. 1015 §§ 6.3.1.1, 6.3.1.2). Petitioner explains that “Gen2 tags
demodulate the received wireless RF input signal, which uses a pulse-
interval encoding (PIE) format, to derive a first digital output signal that
comprises a sequence of digital pulses.” Paper 28, 7–8 (citing Ex. 1015
§§ 6.3.1.2.2, 6.3.1.2.3, Fig. 6.1 (illustrating digital pulses); Ex. 1020 ¶ 363).
Patent Owner does not contest Petitioner’s evidence that Shanks and
Gen2 separately teach the recited demodulator. See Paper 30, 1–12.
Petitioner’s arguments are supported by the cited evidence.
Petitioner’s declarant, Dr. Blalock, provides credible testimonial evidence
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that Shanks’ RF interface portion 1021, as shown in Figure 10, amounts to a
demodulator configured to receive an input signal from an RFID reader and
derive an output signal comprising a sequence of digital pulses, aspects of
which are further illustrated in Shanks’ Figures 30 and 42. See Ex. 1003
¶¶ 159–162. Dr. Blalock also provides credible evidence that the Gen2 tags
demodulate a received wireless RF signal using a pulse-interval encoding
format (PIE). See Ex. 1020 ¶¶ 362–363.
Based on the evidence of record, we are persuaded that Petitioner has
demonstrated that Shanks and Gen 2 each separately teach the recited
limitation.
[22-b]: an interference rejection circuit configured to:
receive the first digital output signal, and filter the first
digital output signal to determine a first time duration
threshold, derive a second digital output signal, by:
setting a filter pass range to detect a delimiter, detecting
the delimiter
Petitioner asserts that the combination of Shanks and Breimesser
teaches this limitation. Paper 28, 8. Petitioner argues that a person of
ordinary skill in the art “would have been motivated to combine Shanks’
data recovery circuit with Breimesser’s circuit, an interference rejection
circuit, to receive the first digital output signal.” Id. (citing Pet. § VI.A.1(c,
d) (claim [1-b, b(i)]); Ex. 1020 ¶ 364). Petitioner argues that “Breimesser’s
circuit would have been configured by setting a test period tp, a filter pass
range, that “can be arbitrarily varied” to filter the first digital output signal
in order to derive a second digital output signal.” Paper 28, 8 (citing Pet.
§ VI.A.1(e, f) (claim [1-b(ii), b(iii)]); Ex. 1007, 1:48–53; Ex. 1020 ¶ 364).
Petitioner argues that a person of ordinary skill in the art “would have been
motivated to form this combination to address a specific need in Shanks to
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filter digital pulses in order to improve the performance of the digital
circuitry by preventing noise pulses from being interpreted as valid data.”
Paper 28, 8 (citing Pet. § VI.A.1(c) (claim [1-b]).
Petitioner also argues that a person of ordinary skill in the art “would
have been motivated to modify Breimesser’s circuit in view of Lichtblau to
include both a first and second test period (e.g., tp-min and tp-max) to filter
(remove) pulses shorter than the first test period (“a low threshold time”)
and also to filter (remove) pulses longer than the second test period (“a high
threshold time”). Paper 28, 8–9 (citing Pet. §§ VI.A.1(f) (claim [1- b(iii)]),
VI.B; Ex. 1020 ¶ 365).
Petitioner further argues that in view of Gen2, it would have been
obvious for a person of ordinary skill in the art “to configure Breimesser’s
circuit in combination with Lichtblau to filter the first digital output signal to
detect a Gen2 delimiter by setting the first and second test period to, for
example, 11.875μs and 13.125μs, a filter pass range, to detect a delimiter
having a ‘12.5μs +/- 5% pulse duration,’ and then detecting the delimiter.”
Paper 28, 9 (citing Ex. 1015 § 6.3.1.2.8, Fig. 6.4; Ex. 1020 ¶ 366).
Patent Owner asserts that Petitioner’s proposed modification to
Breimesser’s circuit sets the wrong pass range. See Paper 30, 4–6. Patent
Owner argues that:
“modify[ing] Breimesser’s circuit to include both a first and
second test period (e.g., tp-min and tp-max),” as NXP alleges
(Paper 28, 8-9), would not have produced a pass range “to filter
(remove) pulses longer than the second test period.” Id. In fact,
implementing a second test period, tp-max, using Breimesser’s
circuit would have resulted in retaining pulses that were longer
than tp-max, as illustrated in the below diagram, where setting
NXP’s tp-max would result in pulses larger than tp-max (e.g.,
~1.7 and ~ 2.0 times longer) to pass through, as opposed to
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passing those pulses that were in the range between tp-min and
tp-max. Ex. 2009, ¶¶ 27-31.
Paper 30, 5 (alteration in original). Patent Owner’s illustration of
Petitioner’s proposed pass range is shown below.

According to Patent Owner, the illustration above, purportedly
showing output pulses from Petitioner’s proposed modification to
Breimesser’s circuit, would allow pulses longer than tp-max to pass through.
Id.
Petitioner points out, however, and we agree, that Patent Owner’s
argument fails to consider Lichtblau’s contribution to Petitioner’s proposed
combination. See Paper 40, 6–8.4 Petitioner argues that Lichtblau teaches
filtering pulses shorter than tp-min and longer than tp-max. Id. at 6 (citing
Paper 28, 8–9). Petitioner explains, and we agree, that Lichtblau teaches “a
pulse train processor 24 that includes ‘minimum and maximum pulse width
detector(s),’ corresponding to a low threshold (e.g., tp-min) and a high
threshold (e.g., tp-max), that ‘are selected to conform to the expected
duration time’ of the expected pulses. Paper 40, 6–7 (citing Pet. 57;
Ex 1008, 5:1–6; Ex. 1003 ¶ 230). Petitioner argues that a person of ordinary
skill in the art “would have been motivated to modify Breimesser’s

4 Petitioner also asserts that Patent Owner’s argument is only relevant to
proposed substitute dependent claims 24, 29, and 34, because “only these
claims recite filtering pulses longer than the pass range.” Paper 40, 6.
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interference rejection circuit based on the teachings of Lichtblau to include a
first and second test period (e.g., tp-min and tp-max), thus providing a filter
pass range to filter pulses shorter than the first test period and pulses longer
than the second test period. Paper 40, 7 (citing Paper 28, 8-9; Pet. §VI.B);
Ex. 1003 ¶¶ 223–225; Ex. 1020 ¶¶ 365, 383–385). Patent Owner’s failure to
consider the contribution of Lichtblau to Petitioner’s proposed combination
undermines Patent Owner’s argument on this point.
Petitioner’s arguments are supported by the cited evidence.
Petitioner’s declarant, Dr. Blalock, provides credible testimonial evidence
that Breimesser’s circuit arrangement, in combination with Shanks and
Lichtblau, can be used for gating out digital pulses or digital pulse gaps and
amounts to the recited interference rejection circuit. See Ex. 1003 ¶ 163;
Ex. 1020 ¶¶ 364–366.
Based on the evidence of record, we are persuaded that Petitioner has
demonstrated that the proposed combination of prior art teaches the recited
claim limitation. We consider Petitioner’s evidence and arguments with
respect to the motivation to combine the prior art, infra.
[22-c] detecting an expected next packet after the
delimiter, and
For this limitation, Petitioner argues that
[a]fter receiving the delimiter, Gen2 tags must detect a data-0
symbol, an expected next packet. Ex. 1015, § 6.3.1.2.8, Fig. 6.4;
Ex. 1020 ¶ 367. That data-0 symbol is then followed by an RTcal
symbol that is “equal to the length of a data-0 symbol plus the
length of a data-1 symbol.” Id. These waveforms calibrate the tag
to interpret subsequent symbols as either data-0 (i.e., shorter than
RTcal / 2) or data-1 (i.e., longer than RTcal / 2). Ex. 1015,
§ 6.3.1.2.8, Fig. 6.4; Ex. 1020 ¶ 367. Gen2’s data-0 and RTcal
waveforms that are received after the delimiter are analogous to
Shanks’ data calibration waveforms that are received after a
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master reset event. Ex. 1006 ¶¶ 477–78, Fig. 26A; Ex. 1020
¶ 367; Pet. §VI.A.1(g) (claim [1-b(iv)]).
Paper 28, 10.
Patent Owner argues that “[s]uch a modification would have detected
the delimiter, but would have rendered a large range of Gen2 Tari values
undetectable.” Paper 30, 8. Patent Owner argues that “[t]he initial pass
range of 12.5μs (± 5%), at best, would have allowed only a small percentage
of Tari values to be detected, but would not have detected the great majority
of possible Gen2-specified Tari values.” Id. at 8–9 (citing Ex. 2009 ¶¶ 38–
46). Patent Owner also argues that Petitioner’s proposed combination
“would also fail to detect any of Gen2’s Tari values in practical
implementations of the system.” Paper 30, 9 (citing Ex. 2009 ¶¶ 43–46).
Petitioner asserts that Patent Owner’s argument is misplaced,
“because [the] claim elements . . . do not recite ‘setting a filter pass range to
detect a delimiter’ and then maintaining that same pass range for ‘detecting
an expected next packet after the delimiter.’” Paper 40, 8–9 (emphasis
added). Petitioner points out that “claim 22 is silent as to whether a different
filter pass range may be set in the purported sequence of operations after
‘detecting the delimiter’ and before ‘detecting an expected next packet.’” Id.
at 9. “Indeed,” Petitioner notes, “none of the proposed claims recite
maintaining the same pass range to detect both a delimiter and an expected
next packet.” Id. Petitioner argues that Patent Owner “did not bother to
analyze the operation of the prior art combination after the filter pass range
had been readjusted in this manner, and did not dispute that altering the filter
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pass range would change the range of pulse widths (Tari values) detected.”
Id. (citing Ex. 1021, 62:24–63:18, 59:5–24).5
We agree with Petitioner. Proposed substitute claim 22 does not
require that the pass range used to detect a delimiter must also be the same
pass range used to detect an expected next packet after the delimiter.
Nothing in claim 22 precludes adjustment of the pass range. Patent Owner’s
argument assumes incorrectly that the pass range used to detect a delimiter
must necessarily be the same pass range used to detect an expected next
packet. Claim 22 has no such restriction and a person of ordinary skill in the
art would understand that there are valid reasons to adjust the pass range.
Indeed, as Dr. Blalock explains:
it would have been obvious that the first and second test periods,
the filter pass range, must be readjusted to detect a command,
such as a Query command, that included valid data-0 symbols
based on pulses as short as 6.25μs or as long as 25μs. Ex. 1015,
§ 6.3.2.10.2.1 (identifying Query command with a four bit code
“1000”). Accordingly, based on the Tari value of the data-0
symbol that was received after the delimiter, an aspect of the
expected next packet, it would have been obvious to adjust the
first and second test periods, the filter pass range, for detecting
a Gen2 Query command.
Ex. 1020 ¶ 371.
We are persuaded that Petitioner has demonstrated that the proposed
combination of prior art teaches the recited claim limitation. We consider
Petitioner’s evidence and arguments with respect to the motivation to
combine the prior art, infra.

5 Petitioner also points out that proposed substitute claim 25 “recites the very
operational sequence that [Patent Owner] complains is required for claim 22:
‘after detecting the delimiter, adjust the filter pass range for detecting the
expected next packet.’” Paper 40, 9.
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[22-d] based on an aspect of the expected next packet,
adjusting the filter pass range for detecting a command,
wherein the interference rejection circuit is configured to
retain digital pulses within the pass range and remove
digital pulses shorter than the pass range. responsive to
the first digital output signal by substantially retaining
digital pulses longer than the first time duration
threshold, and adjust the first time duration threshold
based on at least one aspect associated with the wireless
RF input signal selected from a preamble, a received
packet, a filtered output signal, a data rate, and an
expected next packet.
Petitioner asserts that the combination of Shanks and Breimesser
teaches this limitation. Paper 28, 10–13. Petitioner argues that the
combination would “filter interference pulses shorter than the calibrated
value for the shortest valid signal (e.g., bit ‘0’) to prevent the
misidentification of a noise pulse as a valid data bit. Id. at 11 (citing Pet.
§ VI.A.1(c) (claim [1-b]); Ex. 1020 ¶ 368). Specifically, Petitioner argues, a
person of ordinary skill in the art “would have adjusted Breimesser’s test
period tp based on the duration of data symbols used with a particular data
rate.” Paper 28, 11 (citing Pet. § VI.A.1(g) (claim [1-b(iv)]); Ex. 1020
¶ 368). As a result, Petitioner argues, interference pulses shorter than the
test period would not be interpreted as a logical “0.” Paper 28, 11 (citing
Pet. § VI.A.1(g) (claim [1-b(iv)]); Ex. 1020 ¶ 368).
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Petitioner provides an annotated version of Breimesser’s Figure 2,
shown below.

Breimesser’s Figure 2, annotated by Petitioner and shown above,
depicts a series of digital pulses over time t. Paper 28, 11. According to
Breimesser, Figure 2 shows the mode of operation of Breimesser’s circuit
arrangement depicted in Breimesser Figure 1. Ex. 1007, 3:11–31; Fig. 1. In
Figure 2, above, sequence I shows a series of digital input pulses, A–D, fed
to a first input of gate 1. Id. Sequence II shows a series of counter pulses
fed to a second input of the gate. Id. Sequence III shows individual groups
of output counter pulses that pass through the gate when an input pulse, A–
D, is present. Id. Sequence IV shows decoder output pulses E, F and
sequence V shows storage element output pulses G, H. Id. at 3:51–53, 4:1–
3.
Petitioner also argues that for tags implemented in compliance with
the Gen2 specification, it would have been similarly obvious to filter such
interference pulses. Paper 28, 12 (citing Ex. 1020 ¶ 369). According to
Petitioner, Gen2 specifies that the duration of a data-0 symbol is 1 Tari
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value. Paper 28, 12 (citing Ex. 1015 §§ 6.3.1.2.3, 6.3.1.2.8, Figs. 6.1, 6.4;
Ex. 1020 ¶ 369). “The duration of a RTcal symbol,” Petitioner explains,
“which is equal to the length of a data-0 symbol plus the length of a data-1
symbol,’ is between 2.5 and 3.0 Tari.” Paper 28, 12 (citing Ex. 1015
§§ 6.3.1.2.3, 6.3.1.2.8, Figs. 6.1, 6.4; Ex. 1020 ¶ 369). Petitioner also
explains that Gen2 provides for R=>T communications at a data rate based
on Tari values between 6.25μs and 25μs. Paper 28, 12 (citing Ex. 1015
§ 6.3.1.2.4, Table 6.5. Ex. 1020 ¶ 369).
“To inventory a tag population,” Petitioner argues, “the Gen2
command set includes a ‘Query’ command that ‘initiates an inventory round
and decides which Tags participate in the round (where ‘inventory round’ is
defined as the period between successive Query commands).’” Paper 28, 12
(citing Ex. 1015 §§ 6.3.2.8, 6.3.2.10.2.1; Ex. 1020 ¶ 370). Petitioner points
out that “Gen2 commands, such as the Query command, ‘begin with either a
preamble or a frame-sync.’” Paper 28, 12 (citing Ex. 1015, § 6.3.2.10;
Ex. 1020 ¶ 370).
Petitioner argues that:
[a]fter detecting the Gen2 delimiter where the first and second
test period of Breimesser’s circuit had been set to, for example,
11.875μs and 13.125μs as explained above, it would have been
obvious that the first and second test periods, the filter pass
range, must be readjusted to detect a command, such as a Query
command, that included valid data-0 symbols based on pulses as
short as 6.25μs or as long as 25μs. Ex. 1015, § 6.3.2.10.2.1
(identifying Query command with a four bit code “1000”); Ex.
1020 ¶ 371. Furthermore, Breimesser teaches filtering both high
and low portions of pulses, such as pulse-encoded data-0
symbols. Ex. 1007 2:13-15, 6:63-66, Figs. 3- 4; Ex. 1020 ¶ 372.
Accordingly, based on the Tari value of the data-0 symbol that
was received after the delimiter, an aspect of the expected next
packet, it would have been obvious to adjust the first and second
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test periods, the filter pass range, for detecting a Gen2 Query
command in order for Breimesser’s circuit to retain digital pulses
within the pass range and remove digital pulses shorter than the
pass range.
Paper 28, 12–13 (citing Ex. 1020 ¶ 371).
Patent Owner argues that Breimesser’s circuit does not retain digital
pulses within the pass range because it shortens, lengthens and shifts the
digital pulses. Paper 30, 1–4. Patent Owner argues that:
[a] closer analysis of Breimesser reveals that neither Fig. 2, nor
Fig. 4, describes retaining digital pulses within the pass range.
Fig. 2, at best, produces a shortened output pulse if the input
pulse exceeds the test period, tp. Fig. 4 also shows pulses that are
shortened even if an intervening gap is removed, and notably,
both figures illustrate output pulses (bottom rows V, XII in
annotated Figs. 2 and 4) that are always shifted in time compared
to the input signal.
Id. at 2.
Patent Owner provides annotated versions of Breimesser’s Figures 2
and 4, set out below.

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Breimesser’s Figures 2 and 4, annotated by Patent Owner as shown
above, depict Breimesser’s digital pulse sequences I–V (Fig. 2) and digital
pulse sequences VI–XII (Fig. 4).
Patent Owner argues that:
[u]nlike claim 1, the amended claims simply recite “to retain
digital pulses within the pass range” - without qualifications
regarding substantially removing or retaining the pulses.
Accordingly, the plain language of the claim (as corroborated by
the detailed description (e.g., ‘298 Patent; Figs. 12A-D; Ex.
2001, ¶¶ 50- 52) requires digital pulses within the pass range to
be retained. Ex. 2009, ¶¶ 9-15. Breimesser does not retain digital
pulses within the pass range, but rather produces shortened and
shifted-in-time pulses.
Paper 30, 3. Patent Owner also argues that Petitioner “has failed to address
Breimesser’s express statement that despite any such modifications, the
pulse ‘exhibits an inaccuracy of a maximum of one pulse train length tt.’”
Id. at 4.
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In reply, Petitioner argues that Patent Owner improperly equates the
recited claim language “retain digital pulses” with “retain the exact length of
any digital pulse.” Paper 40, 2. Petitioner argues that “[u]nder [Patent
Owner’s] reasoning, a circuit that ‘shortens, lengthens and shifts the digital
pulses’ does not ‘retain digital pulses,’” and “there can be no ‘inaccuracy’ in
the length of the retained digital pulse—not even less than a clock cycle.”
Id. Petitioner further argues that Patent Owner “does not identify sufficient
evidence to import an absolute ‘no inaccuracy’ limitation into the claims,”
because Figures 12 A–D cited by Patent Owner are only “‘example[s],’ in
which pulse transitions are aligned with ‘clock cycles.’” Id. at 3 (citing
Ex. 1001, 12:22–23, 12:27–30, 12:65–67).
Petitioner argues that the “specification refers to ‘substantially
retaining digital pulses’ (Ex. 1001, 20:48–49, 20:56, 21:12, 21:15–16), but
there is no mention of retaining digital pulses, let alone retaining pulses that
transition during a clock cycle.” Paper 40, 3. Petitioner further argues that
“under PO’s interpretation of ‘retains,’ the proposed claims are indefinite
because they ‘fail to inform, with reasonable certainty, those skilled in the
art about the scope of the invention.’” Id. at 4 (citing Nautilus, Inc. v. Biosig
Instruments, Inc., 572 U.S. 898, 901 (2014)). “If ‘retains the exact length of
any digital pulse’ were the intended scope,” Petitioner argues, Patent Owner
“simply could have proposed claims explicitly reciting that meaning rather
than asking the Board to read limitations into the claims.” Paper 40, 3.
Petitioner also asserts that Patent Owner’s argument “that retained
pulses cannot be shifted-in-time is not supported by the ’298 patent
specification.” Paper 40, 4. Petitioner argues that “Figures 12A-B illustrate
retained pulses that are shifted ‘along a time axis’ ‘with intercepts [of signal
1260] occurring later in time than corresponding intercepts of signal 1210.’”
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Id. (citing Ex. 1001, 12:50–52). Petitioner asserts that Patent Owner’s
expert “agrees ‘the patent teaches that the output signal occurs later in time
than the input signal.’” Paper 40, 4 (citing Ex. 1021, 38:8–11).
Petitioner also argues that “even if ‘retain digital pulses’ means that
output pulses cannot be shortened, Breimesser expressly teaches
embodiments that avoid shortened pulses.” Paper 40, 4. Petitioner asserts
that “Breimesser recognized ‘the pulses of the output signal are shortened’
by the circuit in Figure 1 and explained that ‘[t]his shortening can easily be
cancelled by addition or subtraction.’” Id. at 4–5 (citing Ex. 1007, 5:56–60;
see also id. at 4:5–21 (“The displacement and shortening . . . may be
avoided.”); Paper 28, 8 (citing Pet. §VI.A.1(f)). “In other words,” Petitioner
argues, “Breimesser provides a circuit modification to precisely maintain
pulse widths.” Paper 40, 4–5 (citing Ex. 1003 ¶ 182).
Petitioner further argues that Patent Owner:
fails to acknowledge the teachings of Breimesser’s Figure 3
circuit, which produces an output pulse that is not necessarily
shortened and, even if it were, is accurate within two clock
cycles. Ex. 1007, 7:1-20, Fig. 4 (illustrating output pulse Z and
corresponding input pulse group N to O); Ex. 1021, 51:14-22
(Breimesser “doesn’t say that the embodiment of Figure 3 always
shortens the output.”). [Patent Owner] deceptively represents
that pulse Z is “shorter” (Reply, 2), but [Patent Owner’s] expert
admitted on cross-examination that he simply “assumed” output
pulse Z was shorter, even “though there’s no real indication in
Figure 4 if it is, in fact, shorter or longer.” Ex. 1021, 52:3-12; id.
at 49:6-50:14 (PO’s expert conceded that he did not, and could
not, “count the CLK pulses from N to O and compare that to the
CLK pulses for pulse Z.”)
Paper 40, 5.
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Petitioner also points out that:
Breimesser explains that pulse length inaccuracy arises “due to
the position of the front edge of the input pulse in relation to the
triggering edge of the first counter pulse,” and can be reduced by
increasing the clock frequency (i.e., selecting a smaller tt). Ex.
1007, 4:12-19; see also Ex 1021, 33:13-24 (describing
inaccuracy where pulse “transitions occurred in the middle of a
CLK cycle”). Thus Breimesser teaches that the magnitude of any
inaccuracy can be reduced to the extent necessary as a matter of
design.
Paper 40, 5.
We disagree with Patent Owner. Implicit in Patent Owner’s
arguments is that the proposed claim language, “retain digital pulses,” must
mean that any such digital pulses cannot be altered in any way, such as by
shortening, time-shifting, or creating any type of inaccuracy. Such an
interpretation is not warranted and would require us to improperly read into
the proposed claim language a limitation that is not expressly set out in the
claim or clearly supported by the specification. “Though understanding the
claim language may be aided by the explanations contained in the written
description, it is important not to import into a claim limitations that are not
a part of the claim.” SuperGuide Corp. v. DirecTV Enters., Inc., 358 F.3d
870, 875 (Fed. Cir. 2004).
The proposed claim language reads “adjusting the filter pass range for
detecting a command, wherein the interference rejection circuit is configured
to retain digital pulses within the pass range and remove digital pulses
shorter than the pass range.” The proposed claim language does not require
that the interference rejection circuit “retain unaltered digital pulses” or
“retain the exact length of any digital pulses.” Neither does the proposed
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claim language expressly prohibit retaining digital pulses that have been
shortened, lengthened, time-shifted, or having an inaccuracy.
The ’298 Specification does not define “retain[ing] digital pulses” to
mean excluding digital pulses that have been shortened, lengthened, time-
shifted, or having an inaccuracy. Rather, the ’298 Specification describes an
interference rejection circuit that “substantially remov[es] digital pulses
shorter than a first time duration threshold while substantially retaining
digital pulses longer than the first time duration threshold.” Ex. 1001,
20:47–49; see id. at 21:10–17. Indeed, even Figures 12 A–D cited by Patent
Owner to support its argument are just examples in which pulse transitions
are aligned with clock cycles. See id. at 12:22–23, 12:27–30, 12:65–67.
As Petitioner points out, Patent Owner could have, but did not,
propose substitute claim language that recited “retain[ing] the exact length of
any digital pulses,” or perhaps “retain[ing] unaltered digital pulses” or even
“retain[ing] digital pulses that have not been shortened, lengthened, time-
shifted, or having an inaccuracy.”
Further, to the extent that Breimesser’s circuit shortens output pulses,
Breimesser also teaches embodiments that avoid shortened pulses. As
Petitioner points out, “Breimesser recognized ‘the pulses of the output signal
are shortened’ by the circuit in Figure 1 and explained that ‘[t]his shortening
can easily be cancelled by addition or subtraction.’” Ex. 1007, 5:56–60; see
id. at 4:5–21. In other words, Breimesser provides a circuit modification to
maintain pulse widths. See Ex. 1003 ¶ 182.
As for any inaccuracy in Breimesser’s circuit, Breimesser explains
that pulse length inaccuracy arises “due to the position of the front edge of
the input pulse in relation to the triggering edge of the first counter pulse,”
and can be reduced by increasing the clock frequency. See Ex. 1007, 4:12–
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19. Petitioner points out, and we agree, “in cases where the input pulse and
the counter pulse are aligned, such as in Figure 12A of the patent, this
clocking inaccuracy would not result.” See Paper 40, 5–6.
We are persuaded that Petitioner has demonstrated that the proposed
combination of prior art teaches the recited claim limitation. We consider
Petitioner’s evidence and arguments with respect to the motivation to
combine the prior art, infra.
2. Rationale to Combine the Prior Art
Petitioner asserts that a person of ordinary skill in the art would have
been motivated to combine the teachings of Shanks, Breimesser, Lichtblau,
and Gen 2, such that the proposed substitute claims would have been
obvious at the time of the claimed invention. See Paper 28, 13–18.
Petitioner argues that Shanks and Gen2 teach similar RFID systems such
that it would have been obvious to a person of ordinary skill in the art to
modify Shanks’ pulse-interval encoded signaling system for use in Gen2
systems. See id. at 13–15 (citing Ex. 1020 ¶ 379).
Petitioner acknowledges that Gen2 describes a protocol for
communication, “but does not define any particular circuitry or structure for
implementing a Gen-2 compliant tag.” Paper 28, 15 (citing Ex. 1020 ¶ 379).
Petitioner points out that Shanks provides circuitry to demodulate a wireless
RF input signal from an RFID reader, as well as clocking and counter
circuitry, that could be readily adapted for use in constructing a Gen-2
compliant tag. Id.
Petitioner also argues that a person of ordinary skill in the art “would
have known that interference causing spurious digital output pulses could be
filtered in order to remove pulses that did not conform to certain minimum
or maximum expected pulse durations.” Paper 28, 15 (citing Ex. 1003
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¶ 169). Petitioner argues that such filtering was known for decades prior to
the alleged invention. Paper 28, 15 (citing Ex. 1003 ¶¶ 62–63). Petitioner
points to Breimesser, which “teaches a circuit that ‘can be used for gating
out interference signals of shorter duration than the useful signal.’” Paper
28, 15 (citing Ex. 1007, 7:47–49, 7:63–8:15); see also Ex. 1013, 1:6–11
(“The present invention relates to filters for removing short noise pulses
from digital signals. . . . Noise in a digital transmission may introduce extra
pulses . . . .”).
Petitioner also argues that a person of ordinary skill in the art would
have looked to existing solutions that could be combined with Shanks, such
as Breimesser, to filter pulses arising from interference in a Gen-2 system
and to overcome the known limitations in Shanks’ data recovery circuit.
Paper 28, 15 (citing Ex. 1020 ¶¶ 380–382). Petitioner points out that
Breimesser teaches a circuit for filtering pulses that do not conform to a
minimum expected pulse duration. Paper 28, 16. Petitioner also argues that
a person of ordinary skill in the art “would be motivated to combine
Breimesser’s interference rejection circuit with Shanks,” such that
“interference pulses shorter than the calibrated value for the Gen2 data-0
symbol (e.g., bit ‘0’) would be filtered so that they would not be processed
as invalid data.” Id.
Petitioner argues that “combining the circuits disclosed in Shanks and
Breimesser is a straightforward modification.” Id. (citing Ex. 1003 ¶ 171).
Petitioner points out that Shanks, Breimesser, and Gen2 all “disclose the use
of timing pulse widths for calibration.” Paper 28, 16 (citing Ex. 1020
¶ 383). Petitioner argues a person of ordinary skill in the art “would have
understood that this concept could be expanded to use timing to distinguish
valid pulses from interference pulses.” Paper 28, 16 (citing Ex. 1020 ¶ 383).
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Petitioner also argues that “whereas Breimesser’s circuit is configured
to reject only pulses that do not conform to a minimum duration (i.e, test
period tp), Lichtblau’s ‘pulse train processor . . . is responsive to both the
minimum duration and to the maximum duration of each of the several
pulses.’” Paper 28, 16 (citing Ex. 1008, 2:3–9; Ex. 1003 ¶ 223). “And
Gen2,” Petitioner argues, “provides an explicit motivation for this
combination by specifying, for example, that symbols longer than 4 times
RTcal are not data-1 symbols, but instead are invalid data.” Paper 28, 16
(citing Ex. 1015, § 6.3.1.2.8; Ex. 1020 ¶ 384). “To filter longer pulses
arising from interference that exceed a maximum duration in a Gen2
system,” Petitioner argues, a person of ordinary skill in the art “would have
looked to the teaching of Lichtblau for use in the combination with Shanks
and Breimesser.” Paper 28, 16–17 (citing Ex. 1020 ¶ 384).
“In particular,” Petitioner argues, a person of ordinary skill in the art
“would have been motivated to modify Breimesser’s interference rejection
circuit to include both a first and second test period (e.g., tp-min and tp-max)
to filter pulses shorter than the first test period [] and also to filter pulses
longer than the second test period.” Paper 28, 17 (citing Ex. 1003 ¶ 225;
Ex. 1020 ¶ 385). “To the extent modifications would have been needed to
the combination of Shanks and Breimesser to accommodate a second test
period to filter pulses that exceed a maximum duration,” Petitioner argues,
“such modifications would have been within the level of ordinary skill in the
art at the time of the alleged invention.” Paper 28 (citing Ex. 1020 ¶ 385).
Petitioner argues that the:
combination of these aspects of Shanks, Breimesser, Lichtblau,
and Gen2 represents the use of known techniques (i.e., filtering
digital pulses that do not conform to a minimum expected pulse
duration as Breimesser teaches and to a maximum expected pulse
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duration as Lichtblau teaches) to address a specific need in
Shanks to filter digital pulses in order to improve the
performance of the digital circuitry by preventing noise pulses
from being interpreted as valid data in a Gen2 system.
Paper 28, 17 (citing Ex. 1020 ¶ 386).
Petitioner also argues that the:
proposed combination also amounts to combining prior art
elements according to conventional methods (adding circuitry to
further filter digital pulses) to yield obvious, predictable and
beneficial results from processing a received wireless
communication signal, such as a Gen2 R=>T signal, to eliminate
noise pulses that do not conform to a specified minimum and
maximum pulse duration.
Paper 28, 17–18 (citing Ex. 1020 ¶ 387).
Petitioner further argues a person of ordinary skill in the art “would
have looked to combine Shanks and Gen2 with Breimesser’s circuit
arrangement, including modifications to include a maximum expected pulse
duration as Lichtblau teaches, with a reasonable expectation of success.”
Paper 28, 18 (citing Ex. 1020 ¶ 388). A person of ordinary skill in the art,
Petitioner argues, “would have recognized that combining the teachings of
these references would yield improved performance in cases where the Gen2
tag circuit is subjected to noise pulses not filtered by Shanks’ data recovery
circuit.” Paper 28, 18 (citing Ex. 1020 ¶ 388).
Patent Owner argues that a person of ordinary skill in the art “at the
time of the invention in mid-2000’s, reading Breimesser’s disclosure from
the mid-1970s, would not have been motivated to use Breimesser’s circuit
with inferior pulse-shortening and pulse shifting characteristics to tackle the
noisy, power-starved and dynamic RFID environment, and yet undertake
unspecified modifications to Breimesser’s circuit.” Paper 30, 4 (citing
Ex. 2009 ¶¶ 32–37).
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Patent Owner also argues that a person of ordinary skill in the art
“would not have found it obvious and would not have been motivated to
combine Gen2 with three other references with a reasonable expectation of
success because such a system could not have been used to verify
interrogator compliance as required by Gen2.” Paper 30, 10–11 (citing
Ex. 2009 ¶¶ 47–49).
Patent Owner further argues that a person of ordinary skill in the art
“would have had no reason to change the pass range” as Petitioner proposes,
because:
the initial pass range was already successfully used to detect the
“expected next packet” (and the associated pulse width (PW)).
This detection would have provided the needed information (data
rate and other characteristics) regarding all subsequent Data-0
symbols in the subsequent command. Ex. 2009, ¶¶ 50-52.
Therefore, there would NOT have been a need to change the pass
range to detect subsequent Data-0 symbols associated with the
following command, and [Petitioner’s] assertion that the pass
range must be readjusted is an attempt to fill a gap in the
proposed combination with an arbitrary operation that lacks
logical sense.
Paper 30, 9–10.
We disagree with Patent Owner. With respect to Patent Owner’s
argument concerning the use of Breimesser’s circuit in an RFID
environment, Dr. Blalock first explains that “Shanks’ analog front-end
includes a data recovery circuit to demodulate a wireless RF input signal
from an RFID reader.” Ex. 1003 ¶ 165. “Since the Shanks demodulator is
designed to demodulate signals from a range of frequencies of interest for its
particular application(s),” Dr. Blalock explains, “any interfering signals
within the same range of frequencies will also be processed by the
demodulator.” Id. ¶ 167. Dr. Blalock testifies that a person of ordinary skill
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in the art “would have understood that such a circuit would allow RF
interference to pass through the detector and comparator.” Id. ¶ 168. Dr.
Blalock also testifies that “[a]t the time of the alleged invention, a [person of
ordinary skill in the art] would have known that interference that resulted in
spurious digital output pulses could be further filtered in order to remove
pulses that did not conform to certain minimum or maximum expected pulse
durations.” Id. ¶ 169.
Dr. Blalock further testifies that in order to
filter pulses arising from interference and also to overcome the
known limitations in Shanks data recovery circuit (susceptibility
to interference), a [person of ordinary skill in the art] would have
looked to [] existing solutions that could be combined with
Shanks, such as Breimesser, which discloses a circuit for filtering
pulses that do not conform to an expected pulse duration.
Id. ¶ 170. “The combination of these two circuits,” Dr. Blalock testifies,
“represent[s] the use of known techniques (Breimesser’s pulse filtering
circuit) to address a specific need in Shanks to further filter digital pulses to
improve the performance of the digital circuitry.” Id.
We find Dr. Blalock’s testimony persuasive, reasonably explaining
why a person of ordinary skill in the art at the time of the invention would
have looked to Breimesser’s known filtering circuit to improve Shanks’
RFID data recovery circuit in order to filter out undesirable RF interference.
Patent Owner’s argument with respect to Gen2 compliance is
misplaced. The question is not whether “such a system could not have been
used to verify interrogator compliance as required by Gen2,” as Patent
Owner argues, but rather, “whether there is something in the prior art as a
whole to suggest the desirability, and thus the obviousness, of making the
combination.” In re Fulton, 391 F.3d 1195, 1200 (Fed. Cir. 2004).
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Moreover, “[t]here is no requirement that one of ordinary skill have a
reasonable expectation of success in developing” a system that could be used
to verify interrogator compliance as required by Gen2, as Patent Owner
argues.6 Allergan, Inc. v. Sandoz Inc., 726 F.3d 1286, 1292 (Fed. Cir. 2013).
“Rather, the person of ordinary skill need only have a reasonable expectation
of success of developing the claimed invention.” Id.
Here, Dr. Blalock explains that a person of ordinary skill in the art
“would have referred to Gen2 in developing RFID tags, because Gen2 was
an industry standard that had been ‘designed to work globally and be
approved as an international standard by the International Organization for
Standardization (ISO).’” Ex. 1020 ¶ 375 (citing Ex. 1016, 1). Dr. Blalock
explains that “[l]ike Shanks, Gen2 discloses an RFID system where reader to
tag information is pulse-interval encoded.” Ex. 1020 ¶ 376. Also like
Shanks, Dr. Blalock explains, “Gen2 discloses an RFID system, in which
passive tags backscatter modulate information to a reader,” and “discloses
tags that store information in memory, such as an identification number, that
can be retrieved by a reader.” Id. ¶ 378.
“Given these similarities,” Dr. Blalock testifies persuasively that:
it would have been obvious to [a person of ordinary skill in the
art] to modify Shanks pulse-interval encoded signaling system
for use in Gen2 systems. Gen2 describes a protocol for
communication, but does not define any particular circuitry or
structure for implementing a Gen-2 compliant tag. Shanks
provides circuitry to demodulate a wireless RF input signal from
an RFID reader, as well as for example, clocking and counter

6 Petitioner also points out that Gen2 “section 6.3.1.2.4 describes
requirements for an RFID interrogator, which is not within the scope of the
claims. Instead, the claims recite an RFID tag circuit.” Paper 40, 11 (citing
Ex. 1015, 23).
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circuitry, that could be readily adapted for use in constructing a
Gen2 compliant tag.
Id. ¶ 379.
Dr. Blalock further testifies that:
[u]tilizing both Shanks and Gen2 is simply an example of how
design work is typically done. Gen2 is essentially a design
specification stating the functional requirements of a Reader-Tag
wireless communication protocol. Given the Gen2 specification
that has timing requirements, it is suggestive of hardware for
timing and pulse validation. Rather than start from scratch, it is
typical to look for existing similar designs that could be adapted
to meet the needs of a specification. Shanks describes circuitry
to implement a similar wireless protocol so combining Shanks
with Gen2 is a natural design approach for [a person of ordinary
skill in the art].
Id. ¶ 380.
As for Patent Owner’s argument that a person of ordinary skill in the
art “would have had no reason to change the pass range,” Petitioner
persuasively argues that it would have been obvious to readjust the filter
pass range after receiving the expected next packet because “Gen2 specifies
that the preamble and frame-sync may include a data-0 symbol as short as
6.25μsec or as long as 25μsec. The duration of this data-0 symbol (Tari)
calibrates the tag to interpret subsequent symbols as either data-0 or data-1,”
making it “obvious to adjust the filter pass range based on this calibrated
duration.” Paper 40, 10 (citing Paper 28, 10–13, 20; Ex. 1020 ¶¶ 367–371,
393).
We find that Petitioner has shown by a preponderance of the evidence
that one of ordinary skill in the art at the time of the invention would have
had reason to combine the teachings of the prior art in the manner described
by Petitioner.
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3. Conclusion as to Proposed Substitute Independent Claim 22
Based upon consideration of the entire record, we are persuaded by
Petitioner’s arguments and evidence and determine that Petitioner has
demonstrated by a preponderance of the evidence that proposed substitute
independent claim 22 is unpatentable under 35 U.S.C. § 103(a) as obvious
over the combined teachings of the prior art.
4. Proposed Substitute Independent Claims 27 and 32
As noted, supra, the parties, in general, do not argue proposed
substitute independent claims 27 and 32 separately, relying instead on their
arguments directed to independent claim 22. See Paper 28, 22; Paper 30, 1.
Petitioner, however, does argue the duration determination block limitation
of claim 32 separately. See Paper 28, 23.
The proposed limitation reads:
[32-b]: a duration determination block configured to: count
time durations of the digital pulses; and generate artifact
numbers from the count of time durations; and a counter
configured to generate artifact numbers by counting time
durations of the digital pluses; and
Paper 24, App. A.
Petitioner argues that “in combination with Shanks, Breimesser
counter 2, a duration determination block, would have been configured to
generate a count, artifact numbers, by counting the time durations of the
digital pulses. Paper 28, 22 (citing Pet. § VI.A.5(c) (claim [15-b]); Ex. 1020
¶ 397).
Patent Owner does not specifically address Petitioner’s argument with
respect to this limitation. See generally Paper 30.
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Petitioner’s argument is supported by the cited evidence. We are
persuaded that Petitioner has demonstrated that the proposed combination of
prior art teaches the recited claim limitation.
Based upon consideration of the entire record, and for the reasons
discussed, supra, with respect to proposed substitute independent claim 22,
we are persuaded by Petitioner’s arguments and evidence and determine that
Petitioner has demonstrated by a preponderance of the evidence that
proposed substitute independent claims 27 and 32 are unpatentable under 35
U.S.C. § 103(a) as obvious over the combined teachings of the prior art.
5. Proposed Substitute Dependent Claims 23–26, 28–31, 33–36
As noted above, Petitioner asserts that proposed substitute dependent
claims 23–26, 28–31, and 33–36 (see Paper 24, App. A) are unpatentable as
obvious over the combined teachings of Shanks, Breimesser, Lichtblau, and
Gen2. Paper 28, 18–24.
Petitioner provides evidence and argument showing that the
combination of Shanks, Breimesser, Lichtblau, and Gen2 teaches the
limitations of these proposed substitute dependent claims. Id. Petitioner
also provides evidence and argument that one of ordinary skill in the art
would have combined the teachings of the prior art in the manner described.
Id.
Patent Owner only responds with particularity to Petitioner’s evidence
and argument directed to proposed substitute dependent claim 25. See Paper
30, 11–12. Proposed substitute dependent claim 25 reads as follows:
25. The RFID tag circuit of claim 22, wherein the interference
rejection circuit is further configured to, after detecting the
delimiter, adjust the filter pass range for detecting the second
time duration threshold based on at least one of the preamble, the
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received packet, the filtered output signal, the data rate, and the
expected next packet.
Paper 24, App. A.
Petitioner argues that:
[a]fter detecting a Gen2 delimiter where the first and second test
period of Breimesser’s circuit had been set to, for example,
11.875μs and 13.125μs as explained above in section III.B.3
(element 22-b1, b2), it would have been obvious that the first and
second test periods, the filter pass range, must be readjusted for
detecting a data-0 symbol, the expected next packet. Ex. 1020
¶ 392. Specifically, Gen2 specifies that, after receiving the
delimiter, the tag must detect a data-0 symbol as short as 6.25μs
or as long as 25μs (+/- 1%). Ex. 1015, § 6.3.1.2.8; Ex. 1020
¶ 393. Thus, it would have been obvious to adjust the first and
second test periods to detect the shortest possible valid data-0
symbol and the longest possible valid data-0 symbol. Ex. 1020,
¶ 393. Accordingly, claim 25 would have been obvious over
Shanks in view of Breimesser, Lichtblau, and Gen2.
Paper 28, 20.
Patent Owner argues that “[t]here is nothing logical or sensible about
the suggested sequence of pass range modifications” Petitioner provides
with respect to proposed dependent claim 25. Paper 30, 11. Patent Owner
poses the questions:
why would a POSA change the pass range twice for the exact
same stated reason: to detect a data-0 symbol as short as 6.25μs
or as long as 25μs, as NXP proposes in Step (B-1) and again in
Step (C)[?] If the object of changing the pass range were to detect
Data-0 in the range 6.25-25μs, why would it not suffice to make
this change once, given that Data-0 symbols do not change from
the pre-amble to the next command[?]
Id. at 11–12.
But, as Dr. Blalock explains, “once hardware has been designed to
filter the timing of the delimiter, it is a natural next step to continue to use
that hardware to validate the timing of the other expected pulse shapes. Gen2
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specifies the timing for the pulses after the delimiter so in order to continue
to use the timing filter the filter must be adjusted to the expected timing.”
Ex. 1020 ¶ 393.
We have considered the evidence and arguments with respect to
proposed substitute dependent claims 23–26, 28–31, and 33–36. We are
persuaded that Petitioner has demonstrated that the combined teachings of
the prior art meet the recited limitations of these claims and that one of
ordinary skill in the art would have been motivated to combine the prior art
in the manner described.
Based upon consideration of the entire record, we are persuaded that
Petitioner has demonstrated by a preponderance of the evidence that
proposed substitute dependent claims 23–26, 28–31, and 33–36 are
unpatentable under 35 U.S.C. § 103(a) as obvious over the combined
teachings of the prior art.
G. Anticipation Based on ’Hyde 598
Petitioner asserts proposed substitute claims 22–36 are unpatentable
as anticipated under 35 U.S.C. § 102(b) by Hyde ’598. Because Petitioner
has already shown that all of the proposed substitute claims are unpatentable
as discussed supra, we do not reach this additional asserted ground. See
Beloit Corp. v. Valmet Oy, 742 F.2d 1421, 1423 (Fed. Cir. 1984) (“The
Commission . . . is at perfect liberty to reach a ‘no violation’ determination
on a single dispositive issue.”); Boston Sci. Scimed, Inc. v. Cook Grp. Inc.,
809 F. App’x 984, 990 (Fed. Cir. 2020) (recognizing that “[t]he Board has
the discretion to decline to decide additional instituted grounds once the
petitioner has prevailed on all its challenged claims”).
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CONCLUSION
For the foregoing reasons, we cancel claims 1–5, 8–12, and 15–19 of
the ’298 patent, and we deny Patent Owner’s Motion to Amend the ’298
patent to add proposed substitute claims 22–36, as summarized in the
following table:
Motion to Amend Outcome Claims
Original Claims Cancelled by Amendment 1–5, 8–12, 15–19
Substitute Claims Proposed in the Amendment 22–36
Substitute Claims: Motion to Amend Granted
Substitute Claims: Motion to Amend Denied 22–36
Substitute Claims: Not Reached

ORDER
Accordingly, it is
ORDERED that Patent Owner’s Motion to Amend is granted-in-part
as to its non-contingent request to cancel claims 1–5, 8–12, and 15–19; and
FURTHER ORDERED that Patent Owner’s Motion to Amend is
denied-in-part as to substitute claims 22–36.
This is a final decision. Parties to the proceeding seeking judicial
review of the decision must comply with the notice and service requirements
of 37 C.F.R. § 90.2.

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PETITIONER:

David L. Witcoff
Matthew W. Johnson
David Cochran
Thomas Ritchie
Joshua Nightingale
Yury Kalish
JONES DAY
dlwitcoff@jonesday.com
mwjohnson@jonesday.com
dcochran@jonesday.com
twritchie@jonesday.com
jrnightingale@jonesday.com
ykalish@jonesday.com

PATENT OWNER:

Christina J. McCullough
Amy Simpson
Babak Tehranchi
Daniel Keese
PERKINS COIE LLP
mccullough-ptab@perkinscoie.com
Simpson-ptab@perkinscoie.com
tehranchi-ptab@perkinscoie.com
keese-ptab@perkinscoie.com