Kathrein USA, Inc. v. Fractus S.A.

1. Case Identification

• Case #: Unassigned
• Patent #: 7,932,870
• Filed: April 9, 2019
• Petitioner(s): KATHREIN USA, INC., T-Mobile USA Inc.
• Patent Owner(s): Fractus SA.
• Challenged Claims: 1, 4, 5, 7, and 9

2. Patent Overview

• Title: INTERLACED MULTIBAND ANTENNA ARRAYS
• Brief Description: The ’870 patent discloses an interlaced multiband antenna array for wireless communications. The invention is described as creating a multiband array by juxtaposing or interleaving conventional mono-band arrays and using a single multiband antenna element at positions where elements from the mono-band arrays would otherwise coincide.

3. Grounds for Unpatentability

Ground 1: Claims 1, 4, 5, 7, and 9 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 teaches an interlaced multiband antenna array that can be formed entirely of "composite" dual-band elements or combinations of mono-band and multi-band elements. Raguenet discloses that its patch radiating element can be a "two-resonator patch," which operates on two frequency bands. Petitioner contended that Shapiro teaches a specific, well-known type of "two-resonator patch"—a dual-band, aperture-coupled stacked patch element—that exhibits the "radio-electric behavior" (i.e., similar radiation and impedance patterns across multiple frequencies) required by the claims but not explicitly detailed in Raguenet. The combination of Raguenet’s array structure with Shapiro’s specific element allegedly teaches all limitations of the challenged claims.
  • Motivation to Combine: A POSITA would combine Shapiro’s stacked patch element into Raguenet’s array because Raguenet explicitly suggests using a "two-resonator patch." Shapiro provides a known, simple, and inexpensive implementation of such a patch. Petitioner asserted this constitutes a simple substitution of one known prior art element for another to obtain predictable results. Furthermore, Shapiro's aperture-fed design is compatible with Raguenet's composite structure, allowing it to work with Raguenet's dipole element without losing functionality.
  • Expectation of Success: A POSITA would have a reasonable expectation of success because Shapiro teaches how to design stacked patches to operate at desired frequencies and achieve specific radiation characteristics by adjusting patch geometry and dielectric layers. These were routine design parameters in the art, and known frequency scaling techniques would allow a POSITA to adapt the combined antenna to operate at any desired cellular bands, such as those recited in dependent claims 7 and 9.

Ground 2: Claims 1, 4, 5, 7, and 9 are obvious over Derneryd.

• Prior Art Relied Upon: Derneryd (WO 98/37592).

• Core Argument for this Ground:

  • Prior Art Mapping: Petitioner argued that Derneryd, as a single reference, discloses every element of the challenged claims. Derneryd teaches a base station antenna array with dual-band, stacked-patch elements arranged in a two-dimensional or linear array. These arrays operate simultaneously in two different mobile communication frequency bands (e.g., 800-900 MHz and 1800-1900 MHz). Petitioner contended that Derneryd’s stacked patch element is a type of "multiband antenna" explicitly embraced by the ’870 patent and that its array configuration, where dual-band elements occupy every position, results from a "juxtaposition" of two mono-band arrays as construed by the Petitioner.
  • Motivation to Combine (Single Reference): As this is a single-reference ground, no combination is required. Petitioner argued that even if Derneryd does not explicitly describe the radio-electric behavior with the patent’s exact phrasing, a POSA would have been motivated to tailor Derneryd's elements to have similar radiation and impedance patterns, as this was a fundamental design goal for base station antennas.
  • Expectation of Success: A POSA would reasonably expect to successfully implement Derneryd’s teachings to meet all claim limitations. Derneryd discloses sizing patches using well-known frequency scaling concepts, and a POSA would know how to adjust design parameters (e.g., slot length, dielectric materials) to ensure the antenna was functional with matched impedance and similar radiation patterns at the desired frequencies.

• Additional Grounds: Petitioner noted the concurrent filing of a separate petition against the ’870 patent asserting distinct grounds of unpatentability, including anticipation and obviousness challenges based on Lindmark-I (a 1998 IEEE conference proceeding), Huynh (Patent 5,307,075), and Snygg (Patent 6,239,750).

4. Key Claim Construction Positions

• "multiband antenna": Petitioner argued this term should be construed according to its definition in the ’870 patent's specification: an antenna formed by electromagnetically coupled elements that interact to produce similar radiation and impedance patterns in multiple frequency bands. This construction is central to arguing that prior art elements like those in Shapiro and Derneryd meet the functional requirements of the claims.
• "juxtaposition of a plurality of mono-band arrays": Petitioner contended this phrase describes a conceptual framework for the final positioning of elements, not a manufacturing process. Under this view, an array consisting entirely of identical multiband elements (as shown in Raguenet and Derneryd) can be the result of a "juxtaposition," which is critical for applying that prior art to the claims.

5. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial under §314(a) (e.g., based on General Plastic factors) would be inappropriate. The key reasons asserted were: (1) the ’870 patent has not been the subject of any prior or pending post-grant proceedings; (2) Petitioners (Kathrein and T-Mobile) are not parties to the parallel district court litigations involving the patent; and (3) the IPR challenges claims that are not at issue in the district court cases. Therefore, Petitioner contended that the concerns about follow-on petitions that underpin such denials do not apply.

6. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 1, 4, 5, 7, and 9 of the ’870 patent as unpatentable.