ZTE USA Inc v. Fractus SA

1. Case Identification

• Case #: IPR2018-01463
• Patent #: 9,362,617
• Filed: August 3, 2018
• Petitioner(s): ZTE (USA), Inc.
• Patent Owner(s): Fractus S.A.
• Challenged Claims: 1-4, 6-20

2. Patent Overview

• Title: Multilevel Antennas
• Brief Description: The ’617 patent discloses multilevel antennas designed for multiband operation in compact electronic devices. The technology is based on using repeating geometric elements (e.g., polygons) that are electromagnetically coupled to form a larger, complex structure, enabling a small antenna to operate efficiently across multiple frequency bands.

3. Grounds for Unpatentability

Ground 1: Claims 1-4 and 6-20 are obvious over Misra I in view of Misra II.

• Prior Art Relied Upon: Misra I (a 1998 IEEE journal article) and Misra II (a 1996 journal article).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Misra I discloses the core limitations of the challenged claims. Misra I describes a compact, multiband Concentric Microstrip Triangular Ring Antenna (CMTRA) composed of three concentric triangular rings. Petitioner asserted this structure is a multilevel antenna usable at three distinct frequency ranges, as shown in Misra I’s Table I. The overall structure (a triangle) and its constituent elements (nine four-sided polygons forming the legs of the rings) represent two levels of detail. Petitioner contended that Misra I's design meets the claim requirement that at least 75% of the closed figures have less than 50% of their perimeter in contact with other figures. Furthermore, simulations of the Misra I antenna allegedly show different portions of the antenna radiating at different resonant frequencies, satisfying limitations regarding first, second, and third portions of the structure.
  • Motivation to Combine: Petitioner argued that to the extent Misra I does not explicitly teach that its geometric elements are electromagnetically coupled, Misra II provides the missing disclosure. Misra II, by the same authors, expressly teaches using electromagnetic coupling in a similar concentric square-ring antenna to "significantly enhance the [bandwidth]." A person of ordinary skill in the art (POSITA), seeking to improve the bandwidth of the Misra I antenna, would have been motivated to apply the explicit teaching of electromagnetic coupling from the analogous Misra II design.
  • Expectation of Success: A POSITA would have reasonably expected success in applying the electromagnetic coupling technique from Misra II to the Misra I antenna, as both references describe similar concentric microstrip ring antennas aimed at achieving multiband performance and increased bandwidth.

Ground 2: Claims 1-4 and 6-20 are obvious over Grangeat.

• Prior Art Relied Upon: Grangeat (Patent 6,133,879).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner asserted that Grangeat, which discloses a "multifrequency microstrip antenna" for portable telephones, renders all challenged claims obvious. Grangeat describes an antenna with multiple radiating "zones" that create a multilevel structure capable of operating at three or more frequencies. Petitioner mapped the claimed "first, second, and third portions" to different combinations of Grangeat's radiating zones, which simulations showed are active at different frequency bands. Petitioner argued that Grangeat's structure is composed of multiple four-sided polygons (rectangles) that are electromagnetically coupled and have minimal contact area, meeting key structural limitations. The antenna is explicitly for "portable telephones," satisfying the device limitation. Petitioner further provided its own simulations of the Grangeat antenna to argue that it provides a substantially similar impedance and radiation pattern across its operating frequencies, as required by the claims. The structure is also argued to be "non-convex" as claimed, because a line connecting points in different zones would cross empty slots not part of the antenna structure.

4. Key Claim Construction Positions

• "structure for the multiband antenna": Petitioner proposed construing this term to mean "a multilevel structure...with at least two levels of detail...composed of polygons...wherein most (i.e., more than 75%) of the polygons...having an area of contact...that is less than 50% of the perimeter or area." This construction was central to Petitioner's argument, as it imports key features from the specification into the claim, which Petitioner then mapped to the prior art.
• "a [second/third] portion located substantially within the first portion": Petitioner argued this should be construed as a portion being "substantially inside or enclosed by the first portion," where the portions differ in size or configuration. This construction supports mapping the prior art's concentric ring or nested zone structures to the claims.
• "closed figures bounded by the same number of sides": Petitioner proposed a narrow construction of "straight-side polygon bounded by the same number of straight sides..." This was used to map the four-sided polygons of Misra I and Grangeat to the claims.

5. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial under 35 U.S.C. §325(d) would be inappropriate. Although the prior art references (Misra I, Misra II, and Grangeat) were listed in an Information Disclosure Statement (IDS) during prosecution, Petitioner contended there is no evidence the Examiner substantively considered the specific disclosures or applied them against the claims. Petitioner asserted that the current petition presents the references in a new light, supported by expert testimony and detailed claim charts, creating a record that differs significantly from what was before the Examiner.

6. Relief Requested

• Petitioner requested the institution of an inter partes review and the cancellation of claims 1-4 and 6-20 of the ’617 patent as unpatentable.