PTAB

IPR2019-00947

Kathrein USA Inc v. Fractus SA

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: INTERLACED MULTIBAND ANTENNA ARRAYS
  • Brief Description: The ’918 patent relates to multiband antenna arrays for wireless communication. The technology describes creating an interlaced array by the juxtaposition of conventional mono-band antenna arrays, where a multiband antenna element is used at positions where elements from two or more mono-band arrays would coincide.

3. Grounds for Unpatentability

Ground 1: Claims 1, 5, 9, 12, and 25 are obvious over Raguenet in view of Shapiro.

  • Prior Art Relied Upon: Raguenet (Patent 5,434,580) and Shapiro (Patent 5,043,738).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Raguenet disclosed an interlaced multiband antenna array with "composite" radiating elements operating simultaneously on multiple frequencies. Raguenet’s composite element could include a "two-resonator patch," which by definition operates on two frequency bands. Petitioner asserted that while Raguenet did not detail the radio-electric behavior of this patch (i.e., similar radiation and impedance patterns across bands), Shapiro disclosed a well-known type of two-resonator patch—a dual-band, aperture-coupled stacked patch—that provided such predictable multiband performance. The combination of Raguenet’s two-resonator patch with its dipole element would operate on three simultaneous frequencies, teaching the limitation of claim 9.
    • Motivation to Combine: A POSITA would combine Shapiro's well-characterized stacked patch element with Raguenet's array architecture. This combination represented a simple substitution of one known element (Shapiro's patch) for a less-defined component (Raguenet's "two-resonator patch") to achieve the predictable and desirable performance characteristics taught by Shapiro. Stacked patch elements were common, inexpensive, and known to be suitable for multiband arrays.
    • Expectation of Success: A POSITA would have a reasonable expectation of success. Shapiro taught how to design stacked patches to operate at desired frequencies (such as the 900 MHz and 1800 MHz bands recited in claim 12) with specific impedance and radiation characteristics by varying the patch sizes and dielectric layers, a common practice in antenna design.

Ground 2: Claims 1, 5, 9, 12, 15, 22, 24, 25, and 27 are obvious over Derneryd.

  • Prior Art Relied Upon: Derneryd (WO 98/37592).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that Derneryd taught a base station antenna array composed entirely of stacked-patch dual-band elements, as shown in its Figures 6 and 13. This configuration inherently resulted from the "juxtaposition" of a high-frequency mono-band array and a low-frequency mono-band array, where a single multiband element occupies each position. Derneryd explicitly disclosed arrays for cellular bands around 800-900 MHz and 1800-1900 MHz, directly teaching the limitations of claims 12 and 15. The disclosed stacked-patch elements were square, meeting the limitation of claim 27.
    • Motivation to Combine (Modify): Although a single-reference ground, Petitioner argued a POSITA would have been motivated to ensure Derneryd's elements had similar radiation and impedance patterns across bands. This is a fundamental design criterion for any functional multiband base station antenna intended for simultaneous operation, a point Petitioner noted the Patent Owner had acknowledged in related litigation.
    • Expectation of Success: A POSITA would expect success in achieving the desired radio-electric properties. Derneryd disclosed sizing the individual patches using well-known concepts of frequency scaling to match impedance. A POSITA would understand that this technique also allows for tailoring the radiation patterns to be similar across the intended operating bands.

Ground 3: Claims 1, 5, 9, 12, 15, 22, 24, 25, and 27 are obvious over Snygg.

  • Prior Art Relied Upon: Snygg (Patent 6,239,750).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner contended that Snygg taught a multiband antenna array using a combination of multiband stacked-patch elements interleaved with mono-band elements. The petition emphasized that the physical arrangement shown in Snygg's Figure 4 is "virtually identical" to the embodiment shown in Figure 12 of the challenged ’918 patent. Snygg disclosed that its antenna operates in the GSM 900 and GSM 1800 cellular bands (mapping to claim 12) and that its elements are oriented to provide ±45° double linear polarization (mapping to claim 22).
    • Motivation to Combine (Modify): Similar to the Derneryd ground, Petitioner argued a POSA would be motivated to construct the multiband elements in Snygg to have similar impedance and radiation patterns. Because Snygg’s antenna was designed for base station communication systems operating in well-known cellular bands, achieving such performance for simultaneous operation was a primary and well-understood design requirement.
    • Expectation of Success: A POSA would have a reasonable expectation of success by applying known techniques to Snygg's disclosed aperture-coupled stacked patch structure. It was well within the skill of the art to modify slot length and dielectric layers to control impedance and radiation patterns to achieve the desired similar radio-electric behavior across multiple frequency bands.

4. Key Claim Construction Positions

  • "juxtaposition of a plurality of mono-band arrays": Petitioner asserted this term refers to the conceptual positioning of elements in an interleaved array, consistent with the specification's interchangeable use of "juxtaposition" and "interleaving." Petitioner argued against the Patent Owner's proposed construction from related litigation that required physical "overlapping," contending it is inconsistent with the patent and improperly introduces a mental step.
  • "multiband antenna": Petitioner applied the definition from the ’918 patent's specification, which requires a set of electromagnetically coupled elements that interact to produce "similar" radiation and impedance patterns in multiple frequency bands. This construction was central to Petitioner's arguments that a POSITA would have been motivated to modify prior art elements to meet this known and fundamental design goal.

5. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 1, 5, 9, 12, 15, 22, 24, 25, and 27 of the ’918 patent as unpatentable.