Intel Corp v. ParkerVision Inc

1. Case Identification

• Case #: IPR2020-01302
• Patent #: 7,539,474
• Filed: September 2, 2020
• Petitioner(s): Intel Corporation
• Patent Owner(s): ParkerVision, Inc.
• Challenged Claims: 1, 3, 4, 7, 9–12

2. Patent Overview

• Title: Method and Apparatus for Frequency Down-Conversion
• Brief Description: The ’474 patent relates to systems and methods for down-converting high-frequency electromagnetic signals to lower-frequency signals. The technology utilizes so-called "universal frequency translation" (UFT) modules, which comprise switches and storage elements, to perform the down-conversion process.

3. Grounds for Unpatentability

Ground 1: Anticipation by Larson - Claims 1, 3, 4, and 9–11 are anticipated under 35 U.S.C. §102 by Larson.

• Prior Art Relied Upon: Larson (Lawrence E. Larson, RF and Microwave Circuit Design for Wireless Communications, 1996).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Larson, a pre-AIA reference, disclosed every element of the challenged claims. Specifically, Petitioner asserted that Figure 5.36 of Larson, which illustrates a "singly balanced FET resistive mixer," is an apparatus for down-converting an input signal. This circuit was shown to contain a first and second frequency down-conversion module (each comprising a FET switch and a capacitor as a storage element) that receive an input RF signal and convert it into two separate intermediate frequency (IF) signals based on control signals from a local oscillator. Larson’s circuit then used a "combining module" (disclosed as an "output hybrid or balun") to combine the two IF signals into a single output signal, directly mapping to the limitations of independent claim 1. Petitioner further mapped elements from Larson to show it taught the specific series-coupled storage elements (claim 3), the use of capacitors (claim 4), grounding of reference potentials (claim 9), and the use of IF filters between the conversion modules and the combining module (claim 10), which function as low-pass filters (claim 11).

Ground 2: Obviousness over Larson and Butler - Claims 1, 3, 4, 7, and 9–11 are obvious over Larson in view of Butler.

• Prior Art Relied Upon: Larson (as cited above) and Butler (Patent 4,603,463).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Larson disclosed nearly all limitations of the challenged claims, as detailed in Ground 1. Butler was introduced to teach a "combining module" in the form of a differential amplifier. Butler disclosed a microwave mixer that used a differential amplifier to combine two down-converted IF signals into a single output. Petitioner asserted that substituting Butler's differential amplifier for Larson's balun/output hybrid would have been an obvious modification. This combination also taught the limitations of claim 7, as Larson’s local oscillator signals were disclosed as being 180 degrees out of phase, which corresponds to a delay of 0.5 cycles of the input signal when the input and local oscillator frequencies are the same (a zero-IF condition), a scenario taught by both references.
  • Motivation to Combine: A POSITA would combine Larson and Butler because both references are in the same field of RF mixer design and address the same problem of down-conversion using a balanced mixer architecture. A POSITA would have been motivated to replace Larson's balun with Butler's differential amplifier because differential amplifiers were known to be advantageous for low-frequency or zero-IF applications where baluns can be large or lose DC information.
  • Expectation of Success: A POSITA would have had a high expectation of success because substituting a differential amplifier for a balun was a known, simple substitution of one well-understood subtracting component for another to achieve a predictable result.

Ground 3: Anticipation by Arpaia - Claim 12 is anticipated under 35 U.S.C. §102 by Arpaia.

• Prior Art Relied Upon: Arpaia (Patent 6,192,225).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner contended that Arpaia, which disclosed a "direct conversion receiver," taught every step of the method recited in claim 12. Arpaia’s Figure 5 showed a receiver that receives an I/Q modulated RF input signal and splits it into four channels. Each channel used a mixer to down-convert the signal, creating four distinct down-converted signals: a non-inverted I-phase signal, an inverted I-phase signal, a non-inverted Q-phase signal, and an inverted Q-phase signal. Arpaia then disclosed combining the I and inverted-I signals with a first subtractor to form a first output signal (the final I-phase signal) and combining the Q and inverted-Q signals with a second subtractor to form a second output signal (the final Q-phase signal). This process directly mapped to the sequential steps recited in method claim 12.

4. Key Claim Construction Positions

• "combining module" (Claim 1): Petitioner argued this term should be construed as a means-plus-function limitation under 35 U.S.C. §112, para. 6, because the claim failed to recite structure for performing the claimed function.
  • Function: "combines the second down-converted signal with the first down-converted signal and outputs a single channel down-converted signal."
  • Corresponding Structure: The structure disclosed in the ’474 patent was identified as a "subtractor and/or amplifier," with a differential amplifier being a specific example. This construction was central to mapping Larson's balun and Butler's differential amplifier to the claim.

5. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial under Fintiv would be inappropriate. The petition was filed promptly (6.5 months after litigation began), and the parallel district court case was in a very early stage, with fact discovery stayed and a trial date more than a year away. Petitioner also noted that the IPR challenged claims not asserted in the litigation, making the proceedings non-duplicative. Finally, Petitioner emphasized the strong merits of the petition and the fact that the asserted prior art had not been considered by the USPTO during prosecution, arguing that institution would serve overall system efficiency.

6. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 1, 3, 4, 7, and 9–12 of Patent 7,539,474 as unpatentable.