DOCKET NO.: 0107131-00573US5
`Filed on behalf of Intel Corporation
`By: David L. Cavanaugh, Reg. No. 36,476
`John V. Hobgood, Reg. No. 61,540
`Benjamin S. Fernandez, Reg. No. 55,172
`Wilmer Cutler Pickering Hale and Dorr LLP
`1875 Pennsylvania Ave., NW
`Washington, DC 20006
`Tel: (202) 663-6000
`Email:
`David.Cavanaugh@wilmerhale.com
`John.Hobgood@wilmerhale.com
`Ben.Fernandez@wilmerhale.com
`
`UNITED STATES PATENT AND TRADEMARK OFFICE
`____________________________________________
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`____________________________________________
`
`INTEL CORPORATION
`Petitioner
`
`v.
`
`QUALCOMM INCORPORATED
`Patent Owner
`
`Case IPR2019-00129
`
`DECLARATION OF PATRICK FAY, PH.D.
`U.S. PATENT NO. 9,154,356
`CHALLENGING CLAIMS 2, 3, 4, 5, 6, and 10
`
`INTEL 1402
`
`

`

`
`
`TABLE OF CONTENTS
`
`Page
`INTRODUCTION ........................................................................................... 1 
`I. 
`UNDERSTANDING OF THE LAW .............................................................. 4 
`II. 
`III.  BACKGROUND TECHNOLOGY ............................................................... 10 
`A. 
`Basic Receiver Front End .................................................................... 10 
`B. 
`Low Noise Amplifiers ......................................................................... 15 
`1. 
`Cascode Configuration .............................................................. 16 
`Carrier Aggregation ............................................................................. 18 
`C. 
`D.  Optional Receiver Circuits .................................................................. 22 
`1. 
`Impedance Matching Circuits ................................................... 22 
`2. 
`Attenuation Circuit .................................................................... 24 
`3. 
`Inductors .................................................................................... 25 
`IV.  OVERVIEW OF THE ’356 PATENT .......................................................... 26 
`A. 
`Independent Claim 1 ........................................................................... 27 
`LEVEL OF ORDINARY SKILL IN THE ART ........................................... 31 
`V. 
`VI.  CLAIM CONSTRUCTION .......................................................................... 32 
`A. 
`“carrier aggregation” ........................................................................... 32 
`VII.  SUMMARY OF THE PRIOR ART REFERENCES .................................... 34 
`A.  U.S. Patent Application Publication 2012/0056681 (“Lee”) .............. 34 
`B. 
`3GPP TR 36.912 Feasibility study for Further Advancements
`for E-UTRA (LTE-Advanced) (Release 9) (“Feasibility Study”) ...... 39 
`Digitally-Controlled RF Passive Attenuator in 65 nm CMOS for
`Mobile TV Tuner ICs (“Youssef”) ...................................................... 40 
`VIII.  SUMMARY OF CONCLUSIONS ............................................................... 43 
`IX. 
`INVALIDITY OF THE CHALLENGED CLAIMS ..................................... 44 
`
`C. 
`
`i
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`

`

`B. 
`
`A.  Ground I: Claims 2, 3, 4, 5, and 6 Are Anticipated by Lee ............... 44 
`1. 
`Claim 1 ...................................................................................... 44 
`2. 
`Claim 2 ...................................................................................... 61 
`3. 
`Claim 3 ...................................................................................... 64 
`4. 
`Claim 4 ...................................................................................... 66 
`5. 
`Claim 5 ...................................................................................... 68 
`6. 
`Claim 6 ...................................................................................... 70 
`Ground II: Claim 10 Is Obvious Over Lee in View of Youssef ......... 87 
`1. 
`Claim 10 .................................................................................... 87 
`Ground III: Claims 2, 3, 4, 5, and 6 Are Obvious Over Lee in
`View of the Feasibility Study .............................................................. 95 
`D.  Ground IV: Claim 10 Is Obvious Over Lee in View of the
`Feasibility Study and Youssef ........................................................... 100 
`X.  AVAILABILITY FOR CROSS-EXAMINATION .................................... 102 
`XI.  RIGHT TO SUPPLEMENT ........................................................................ 102 
`XII.  JURAT ......................................................................................................... 103 
`
`C. 
`
`
`
`ii
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`

`

`I.
`
`INTRODUCTION
`
`1. My name is Patrick Fay.
`
`2.
`
`I am a Professor with tenure in the Department of Electrical
`
`Engineering at the University of Notre Dame. I earned a Bachelor of Science in
`
`Electrical Engineering from the University of Notre Dame in 1991, a Master of
`
`Science in Electrical Engineering from the University of Illinois at Urbana-
`
`Champaign in 1993, and a Doctorate (Ph.D.) degree in Electrical Engineering
`
`from the University of Illinois at Urbana-Champaign in 1996.
`
`3.
`
`I have approximately 22 years of experience in the field of electrical
`
`engineering, with particular experience in the field of RF transceivers, RF front
`
`ends, and related components. I have been the Director of the Notre Dame
`
`Nanofabrication Facility since 2003 and established the High-Speed Circuits and
`
`Devices Laboratory at Notre Dame in 1998.
`
`4.
`
`For example, I have worked and published extensively on high-
`
`frequency devices suitable for use in low noise amplifiers, mixers, and oscillators,
`
`all of which are fundamental components of RF receivers and RF front ends. I
`
`have also published on compact models needed to design circuits with these
`
`devices, as well as benchmarking studies comparing these technologies to current
`
`approaches.
`
`1
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`

`

`5.
`
`I have taught graduate and undergraduate level courses at the
`
`University of Illinois and at Notre Dame in electrical engineering, semiconductor
`
`devices, circuit design, and microwave circuit design. I regularly teach courses in
`
`analog circuit design. I developed and teach a course on RF and Microwave
`
`Circuits for Wireless Communications that combines classwork as well as
`
`laboratory measurements and design, with a focus on RF receivers. For these
`
`efforts, I was awarded the College of Engineering’s Outstanding Teacher Award
`
`in 2015.
`
`6.
`
`I have authored or co-authored more than 150 peer-reviewed technical
`
`publications, more than 160 conference presentations, and have 9 U.S. patents,
`
`with others pending, in the areas of inter-chip communication, semiconductor
`
`devices for low-power applications, and semiconductor devices for high-
`
`frequency applications. My resume includes a sample list of these publications.
`
`7.
`
` I was named fellow of the Institute of Electrical and Electronics
`
`Engineer (IEEE) in 2016, which is the highest grade of membership conferred by
`
`the IEEE Board of Directors on an individual member.
`
`8.
`
`In my time as a faculty member at Notre Dame, I have received grants
`
`to support research in device technologies suitable for high-performance RF
`
`applications. This work has been supported by the Office of Naval Research
`
`(ONR), the Defense Advanced Research Projects Agency (DARPA), the National
`
`2
`
`

`

`Science Foundation (NSF), and industrial collaborators. This has enabled me to
`
`establish an externally-funded research program in high-speed electronic and
`
`optoelectronic devices and circuits.
`
`9.
`
`A copy of my CV is attached as Appendix A.
`
`10.
`
`I have reviewed the specification, file history (including the cited
`
`references) and claims of U.S. Patent No. 9,154,356 to Aleksandar Miodrag Tasic
`
`and Anosh Davierwalla (the “’356 patent”).
`
`11.
`
`I have reviewed and understand the following references:
`
` U.S. Patent Application Publication 2012/0056681 (“Lee” (EX1435-
`
`Lee))
`
` 3GPP TR 36.912 V9.1.0; 3rd Generation Partnership Project;
`
`Technical Specification Group Radio Access Network; Feasibility
`
`study for Further Advancements for E-UTRA (LTE-Advanced)
`
`(Release 9) (“Feasibility Study” (EX1404-Study))
`
` “Digitally-Controlled RF Passive Attenuator in 65 nm CMOS for
`
`Mobile TV Tuner ICs,” by Ahmed Youssef and James Haslett
`
`(“Youssef” (EX1409-Youssef))
`
`12.
`
`I have been retained by Intel Corporation (“Petitioner”) to provide my
`
`conclusions concerning the validity of the ’356 patent in connection with its
`
`petition for inter partes review of the ’356 patent.
`
`3
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`

`

`13.
`
`I am being compensated at my normal consulting rate of $450 per
`
`hour for my work. My compensation is not in any way dependent on the outcome
`
`of any inter partes review, and in no way affects the substance of my statements
`
`in this declaration, nor have I any financial or personal interest in the outcome of
`
`this proceeding.
`
`14. To the best of my knowledge, I have no financial interest in Petitioner,
`
`or in the ’356 patent. To the extent any mutual funds or other investments I own
`
`have a financial interest in the Petitioner or the ’356 patent, I do not knowingly
`
`have any financial interest that would affect or bias my judgment.
`
`II. UNDERSTANDING OF THE LAW
`
`15.
`
`I am not an attorney. For the purposes of this declaration, Petitioner’s
`
`counsel has informed me about certain aspects of the law that are relevant to my
`
`analysis and conclusions. My understanding of the law is as follows:
`
`16. A patent is presumed valid, and a challenger to the validity of a patent
`
`must show invalidity of the patent by clear and convincing evidence. Clear and
`
`convincing evidence is evidence that makes a fact highly probable.
`
`17. A patent claim is invalid if it is “anticipated” by prior art. For a claim
`
`to be invalid because it is anticipated, all of its requirements must have existed in
`
`a single device or method that predates the claimed invention or must have been
`
`4
`
`

`

`described in a single publication or patent, either expressly, inherently, or
`
`implicitly, that predates the claimed invention.
`
`18. The description in a written prior art reference does not have to be in
`
`the same words as the claim, but all the requirements of the claim must be there,
`
`either stated, necessarily implied (i.e., inherent), or implied, so that someone of
`
`ordinary skill in the art, looking at that one reference, would be able to make and
`
`use the claimed invention based on the reference.
`
`19. A patent claim is also anticipated if there is clear and convincing
`
`proof that, more than one year before the filing date of the patent, the claimed
`
`invention was: patented anywhere in the world; or described in a printed
`
`publication anywhere in the world.
`
`20. A patent claim is invalid if the claimed invention would have been
`
`obvious to a person of ordinary skill in the art at the time the application was filed.
`
`This means that even if all the requirements of a claim cannot be found in a single
`
`prior art reference that would anticipate the claim or constitute a statutory bar to
`
`that claim, the claim is invalid if it would have been obvious to a person of
`
`ordinary skill at the time of the alleged invention. That is, the claim is obvious if
`
`the person of ordinary skill could adapt the reference to meet the claim by
`
`applying known concepts to achieve expected results.
`
`5
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`

`

`21. The determination of whether a claim is obvious should be based
`
`upon several factors, including:
`
` the level of ordinary skill in the art that someone would have had at
`
`the time of the claimed invention;
`
` the scope and content of the prior art; and
`
` what differences, if any, existed between the claimed invention and
`
`the prior art.
`
`22.
`
`In considering the question of obviousness, it is also appropriate to
`
`consider any objective indicia (or secondary considerations) of obviousness or
`
`non-obviousness that may be shown. These include:
`
` whether a product that practices the claimed invention has achieved
`
`commercial success, to the extent any such success is due to the
`
`merits of the claimed invention;
`
` whether a long-felt need existed in the prior art for the solution
`
`provided by the claimed invention;
`
` whether there were unsuccessful attempts by others to find the
`
`solution provided by the claimed invention;
`
` whether there was copying of the claimed invention by others;
`
` whether there were unexpected and/or superior results from the
`
`claimed invention;
`
`6
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`

`

` whether there was acceptance by others of the claimed invention as
`
`shown by praise from others in the field or from the licensing of the
`
`claimed invention; and
`
` whether there was independent invention of the claimed invention by
`
`others before or at about the same time the named inventor conceived
`
`of it.
`
`23.
`
`I further have been informed and understand that a “nexus” must exist
`
`between the claimed invention and the alleged commercial success. In other
`
`words, proof of commercial success of a product that practices the claimed
`
`invention is not enough; there must be evidence that the commercial success
`
`resulted, at least in meaningful part, from the claimed invention.
`
`24.
`
`I have been informed and understand a patent claim composed of
`
`several elements is not obvious merely because each of its elements was
`
`independently known in the prior art. In evaluating whether such a claim would
`
`have been obvious, it is relevant to consider if there would have been a reason that
`
`would have motivated a person of ordinary skill in the art to combine the known
`
`elements or concepts from the prior art in the same way as in the claimed
`
`invention. For example, market forces or other design incentives may be what
`
`produced a change, rather than true inventiveness. It is also appropriate to
`
`consider:
`
`7
`
`

`

` whether the change was merely the predictable result of using prior art
`
`elements according to their known functions, or whether it was the
`
`result of true inventiveness;
`
` whether there is some teaching or suggestion in the prior art to make
`
`the modification or combination of elements claimed in the patent;
`
` whether the innovation applies a known technique that had been used
`
`to improve a similar device or method in a similar way; or
`
` whether the claimed invention would have been obvious to try,
`
`meaning that the claimed innovation was one of a relatively small
`
`number of possible approaches to the problem with a reasonable
`
`expectation of success by those of ordinary skill in the art.
`
`25.
`
`In considering obviousness, it is important to be careful not use the
`
`benefit of hindsight.
`
`26. A single prior art reference can alone render a patent claim obvious, if
`
`any differences between that reference and the claims would have been obvious to
`
`a person of ordinary skill in the art at the time of the alleged invention—that is,
`
`the patent claim is obvious if a person of ordinary skill could readily adapt the
`
`prior art reference to meet the claim by applying known concepts to achieve
`
`expected results.
`
`8
`
`

`

`27.
`
`I have been informed that claim construction is a matter of law and
`
`that the final claim construction will ultimately be determined by the Board. For
`
`the purposes of my analysis in this proceeding and with respect to the prior art, I
`
`have been informed that patents are currently reviewed in an inter partes review
`
`(IPR) proceeding under the “broadest reasonable interpretation” standard
`
`(hereinafter “BRI standard”).
`
`28.
`
`I have been informed that the BRI standard refers to the broadest
`
`reasonable interpretation that a person of ordinary skill in the art would give to a
`
`claim term in light of the specification.
`
`29.
`
`I have been informed that under the Phillips standard, claim terms are
`
`generally given their plain and ordinary meaning as understood by a person of
`
`ordinary skill in the art at the time of the invention, with the claim term read not
`
`only in the context of the particular claim in which the disputed term appears, but
`
`also in the context of the entire patent, including the specification.
`
`30.
`
`I have been informed that the Patent Owner can serve as his or her
`
`own lexicographer. As such, if a claim term is provided with a specific definition
`
`in the specification, that claim term should be interpreted in light of the particular
`
`definition provided by the Patent Owner.
`
`9
`
`

`

`III. BACKGROUND TECHNOLOGY
`
`31.
`
`I understand that the ’356 patent issued from U.S. App. No.
`
`13/590,423, which was filed on August 21, 2012, and that it claims priority to
`
`provisional application U.S. Provisional Application No. 61/652,064, which was
`
`filed on May 25, 2012.1 The apparatus described in the ’356 patent involves
`
`several well-known components and design principles for low noise amplifiers
`
`within a radio frequency (RF) receiver configured to support carrier aggregation
`
`(CA). In this section, I explain the basic operation and characteristics of such
`
`front-end receivers and low noise amplifiers, as well as the principles behind
`
`carrier aggregation. This information was well known in the art before the Patent
`
`Owner’s alleged conception date for the ’356 patent.
`
`A. Basic Receiver Front End
`
`32. A wireless communication system is a system for transmitting and
`
`receiving signals using radios. A receiver within a wireless device, such as a
`
`cellular phone, receives radio frequency signals from various base stations, such
`
`
`1 For purposes of this declaration, I consider May 25, 2012 to be the earliest
`
`priority date of the ’356 patent. I have been informed and understand that Patent
`
`Owner has alleged a conception date of March 25, 2012, in a related matter. The
`
`concepts I describe in this declaration were known before that date.
`
`10
`
`

`

`as cell towers. Each radio frequency signal may fall within a particular radio
`
`frequency band, which defines a range of frequencies in the electromagnetic
`
`spectrum. In the United States, the FCC allocates radio frequency bands for
`
`specific uses, such as FM radio broadcasts or maritime navigation. Each
`
`frequency band contains different carriers, which are subcomponents of the
`
`frequency band used to carry information. Carriers are analogous to channels in
`
`terrestrial broadcast systems (e.g., FM radio) in that each carrier may contain
`
`different information. Additionally, in typical wireless communication
`
`applications (e.g. cellular telephony) carriers can be dynamically assigned to
`
`specific users or applications. For instance, a carrier may be used to transmit a
`
`voice call to one user, and subsequently to provide data for another user.
`
`33. A wireless device contains an antenna that picks up radio frequency
`
`signals from the air. Antennas are not selective and capture both desired and
`
`undesired signals, including signals that are not of interest to the user or wireless
`
`device and signals on frequency bands assigned for other purposes. In order to
`
`extract the desired information from the received signals, the receiver removes the
`
`undesired signals to process only the frequencies on which the relevant
`
`information is carried. To do so, the receiver filters the signal captured by the
`
`antenna, amplifies the signal frequencies that remain after filtering, and down
`
`11
`
`

`

`converts2 the signal using “mixers” to enable further processing. Figure 1, shown
`
`below, is an illustration of the “direct-conversion” receiver used in the ’356 patent
`
`(see EX1401-’356-Patent at Fig. 4B) that includes an antenna for receiving the
`
`signals (in light blue), a low noise amplifier for amplifying the signals (in red),
`
`mixers for down conversion (in navy), and various filters for removing undesired
`
`signals (in yellow and green).
`
`
`
`Figure 1. A direct-conversion receiver containing an antenna, a band-
`
`pass filter, a low noise amplifier, and two mixers coupled to low-pass
`
`filters.
`
`34. The antenna in the receiver shown in Figure 1 captures a variety of
`
`signals from the air. The band-pass filter (BPF) attenuates (effectively removes)
`
`
`2 Down conversion centers the frequencies in a signal at a lower frequency range.
`
`12
`
`

`

`all frequencies that fall outside the desired frequency band.3 The low noise
`
`amplifier increases the power of the remaining carriers.4 Finally, the mixers down
`
`convert the signal to enable the low-pass filters (LPFs) to extract the relevant
`
`information on particular carriers. The ’356 patent implements the same basic
`
`receiver structure, which was commonly used in wireless communication systems
`
`before the Patent Owner’s alleged conception date for the ’356 patent. See, e.g.,
`
`EX1401-’356-Patent at Fig. 4B. I have drawn Figures 2-5 below to illustrate
`
`these various processing steps.
`
`
`
`
`
`
`3 Attenuation is the opposite of amplifying. Although an amplifier increases the
`
`power, or amplitude, of a signal, resulting in a “gain,” a filter decreases the
`
`amplitude of undesired frequencies.
`
`4 The amplification – or increase in the power of the signal – is called its “gain.”
`
`13
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`

`

`
`Figure 2. The antenna receives signals over a wide range of frequencies,
`
`only some of which carry the desired information.
`
`
`Figure 3. A band-pass filter reduces the power of frequencies outside the
`
`desired frequency band, effectively removing them.
`
`14
`
`

`

`Figure 4. A mixer shifts the frequencies to a lower range, in order to enable
`
`
`
`further processing.
`
`Figure 5. Additional filters, such as a low-pass filter, further refine the
`
`signal to select the specific carrier of interest (Ch 2 in this illustration).
`
`
`
`B.
`
`Low Noise Amplifiers
`
`35. A low noise amplifier (“LNA”) is a well-known and widely used
`
`component of the receiver front-end. The purpose of the LNA is to increase the
`
`15
`
`

`

`power of a received signal while introducing minimal “noise.”5 In addition to
`
`providing amplification, LNA designers must also consider a number of other
`
`issues, including gain control and impedance matching, which I describe below.
`
`1.
`Cascode Configuration
`36. A cascode configuration of an amplifier improves isolation, gain, and
`
`bandwidth by using two components called transistors6 arranged in a vertical, or
`
`stacked, configuration, instead of a single transistor. Cascode amplifiers include a
`
`common source “transconductance” transistor that receives an input voltage signal
`
`(Vin) and converts it to current with an applied gain, and a common gate
`
`“cascode” transistor that couples the current to the output signal. In Figure 6
`
`below, Q1 is the transconductance transistor, while Q2 is the cascode transistor.
`
`
`5 Noise refers to random variation in a signal that does not carry information. The
`
`signal-to-noise ratio quantifies the proportion of meaningful information compared
`
`to non-meaningful variation.
`
`6 A transistor is a basic component of amplifier design. A transistor can act either
`
`as a switch or as an amplifier.
`
`16
`
`

`

`I bias
`
`V out
`Cascode
`Transistor
`Transconductance
`Transistor
`
`V bias
`V in
`
`Q 2
`Q 1
`
`
`
`Figure 6. Cascode Amplifier: Q1 is the transconductance transistor and Q2
`
`is the cascode transistor.
`
`37. An amplified output signal (Vout) requires current to flow through the
`
`amplifier. For current to flow, voltage signals must be applied to the gates of both
`
`the transconductance transistor and the cascode transistor. For example, if the
`
`bias voltage (Vbias) provided to the gate of the cascode transistor is too low, no
`
`output will be provided from the amplifier even if the transconductance transistor
`
`continues to receive the RF input voltage signal (Vin). Thus, supplying too low of
`
`a voltage to the gates of either transistor in a cascode amplifier effectively disables
`
`the amplifier.
`
`38. The cascode configuration is a decades-old idea that remains a
`
`popular choice for amplifier design due to its improved performance
`
`characteristics. Indeed, the ’356 patent uses the cascode configuration in the
`
`17
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`

`

`typical fashion of RF communication systems to achieve the known benefits, as
`
`was known at the time of the Patent Owner’s alleged conception date for the ’356
`
`patent.
`
`C. Carrier Aggregation
`
`39.
`
`Information can be transmitted using a single carrier between the
`
`transmitter and the receiver by encoding information on a single base frequency
`
`occupying a particular frequency range. A technique called carrier aggregation
`
`(“CA”), however, allows for the transmission of data on multiple carriers to or
`
`from a radio. Related or unrelated data may be encoded on different carriers and
`
`received simultaneously for concurrent processing. Simultaneous processing can
`
`increase the data rate between the transmitter and receiver by allowing
`
`information to be extracted from multiple carriers at the same time.
`
`40.
`
`Increasing download speeds is one of many uses of carrier
`
`aggregation. By transmitting related or unrelated information over multiple
`
`carriers, carrier aggregation can increase the bandwidth available for transmission.
`
`Carrier aggregation also allows mobile network operators to more efficiently
`
`18
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`

`

`deploy available spectrum and make use of “fragmented spectrum.”7
`
`Aggregating fragmented spectrum increases network throughput even as the total
`
`amount of bandwidth remains constant. As another example, carrier aggregation
`
`can be used to enhance “wireless backhaul,” which refers to back-end
`
`communications between central and peripheral nodes in a communication
`
`network. For example, a corporate internet network can transmit data to an
`
`Internet Service Provider (ISP) using multiple carriers, which enhances overall
`
`network performance.
`
`41. Carrier aggregation can be divided into three categories. Carrier
`
`aggregation between or among carriers that are next to each other in the frequency
`
`spectrum is called intra-band contiguous carrier aggregation. Carrier
`
`
`7 A mobile network operator may own a certain frequency spectrum allocation, i.e.
`
`ranges of frequencies under the operator’s control. Some of those frequency
`
`ranges may be broken up, or separated, by spectrum that the operator does not
`
`own, such as frequency bands owned by others or allocated for other purposes.
`
`This creates “fragmented spectrum” and makes some frequency ranges too narrow
`
`to transmit high-speed data on their own. Carrier aggregation allows the operator to
`
`piece these fragments together to create larger effective bandwidth for use in
`
`transmission of data.
`
`19
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`

`

`aggregation between or among carriers that are in the same frequency band but
`
`not directly adjacent to each other in frequency spectrum is called intra-band
`
`non-contiguous carrier aggregation. Finally, carrier aggregation between
`
`carriers in different frequency bands is called inter-band carrier aggregation. I
`
`have illustrated these varieties of carrier aggregation in Figure 7, below. The
`
`green channels indicate the carriers being aggregated.
`
`
`
`Figure 7. (a) Contiguous intra-band CA, (b) noncontiguous intra-band CA,
`
`and (c) inter-band CA.
`
`42. Because of the bandwidth requirements for processing far-apart
`
`carriers, a receiver configured for carrier aggregation typically uses multiple RF
`
`front-ends on different receive paths. Each receive path supports a particular
`
`range of carriers. As an example, one receive path may support carriers in a first
`
`20
`
`

`

`frequency band, while another receive path may support carriers in a different
`
`frequency band. Figure 8, below, shows one example of a receiver configured to
`
`support carrier aggregation by sending different carriers to different receive paths.
`
`The ’356 patent also uses multiple receive chains to support carrier aggregation
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`because it has multiple “amplifier stages” for different sets of carriers, with each
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`set of carriers processed by a different amplifier stage and corresponding mixer to
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`support carrier aggregation. See EX1401-’356-Patent at 8:10-12, 8:32-35.
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`Figure 8. A carrier-aggregation enabled receiver with two receive
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`paths. Source: U.S. Patent No. 8,442,473 (“Kaukovuori” (EX1425-
`
`Kaukovuori))
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`D. Optional Receiver Circuits
`43.
`In order to address various challenges in LNA design, a variety of
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`design techniques and circuits are used, a few of which I describe below.
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`1.
`Impedance Matching Circuits
`44. LNA design must also address the issue of impedance matching.
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`Impedance is the effective resistance of a circuit to current flow when voltage is
`
`applied. If the impedance of the source—the electrical component that provides
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`the signal power—is not commensurate with the impedance of the load—the
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`electrical component that consumes power—some of the signal may be reflected
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`and power transfer is not maximized. To avoid this problem, LNA designers
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`typically use impedance matching circuits that ensure proper conditions for
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`maximizing power transfer, minimizing signal reflection, and establishing a low
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`noise figure.
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`Figure 9. Impedance mismatch due to discontinuities, which may result in
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`signal reflection and suboptimal power transfer.
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`45. An impedance matching circuit is one solution to the problem of
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`impedance matching. An impedance matching network operating at the input
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`stage is called an input matching circuit or network, while an impedance matching
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`network operating at the output is an output matching network. Many topologies
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`can be used for an impedance matching network, such as the L-network, shown in
`
`Figure 10, below.
`
`
`
`
`
`
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`Figure 10. An impedance matching circuit arranged in an L topology.
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`46. Traditional impedance matching circuits provide ideal impedance
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`matching at only one frequency. Thus, to achieve optimal impedance matching at
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`a variety of different frequencies, LNA designers have turned to tunable matching
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`networks that use components with variable electrical characteristics. Tunable
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`impedance matching networks have become well-known in recent decades and
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`were used before the ’356 patent, and those of ordinary skill in the art knew of the
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`advantages and tradeoffs of using tunable impedance matching networks. For
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`example, tunable matching networks provide higher performance and better noise
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`23
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`figure at the acceptable expense of modestly increased complexity and reduced
`
`bandwidth relative to the other techniques (e.g., use of source degenerative
`
`inductors, feedback-based approaches, or broadband attenuators) discussed below.
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`The ’356 patent applies the idea of tunable matching circuits in a standard way to
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`provide impedance matching and improved noise figure in different modes, as was
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`known in the field of RF communication systems before the Patent Owner’s
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`alleged conception date for the ’356 patent. See EX1401-’356-Patent at 13:47-51.
`
`2.
`Attenuation Circuit
`47. Gain control refers to the need to provide different levels of gain to
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`different signals. A low-power signal may require the LNA to provide a large
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`amount of gain while introducing little noise to avoid overwhelming the signal.
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`By contrast, a high-power signal may require less amplification to avoid distorting
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`the signal, an effect that can come as a result of “clipping.” Clipping occurs when
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`the amplitude of the signal exceeds the ability of the circuit to process the signal.
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`To achieve variable gain, an LNA may be designed to provide different amounts
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`of gain in response to controls that are typically set depending on the
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`characteristics (e.g. amplitude) of the input signal.
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`
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`24
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`

`

`
`
`Figure 11. Signal clipping from excessive gain.
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`48. An attenuation circuit “attenuates,” or reduces the power, of a signal.
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`An attenuation circuit with variable attenuation helps achieve variable gain and
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`increases dynamic range. By using a larger attenuation when the input signals are
`
`at a high-power level, the overall gain is reduced and the linearity is improved;
`
`conversely by using a small attenuation setting increased gain can be achieved
`
`when the input signals are at a low power level. Attenuation can also help avoid
`
`signal clipping, which distorts a signal by exceeding the amplitude range of a
`
`circuit component. Attenuation circuits can also be used to improve impedance
`