ZTE USA Inc v. Fractus SA

1. Case Identification

• Case #: IPR2018-01455
• Patent #: 7,394,432
• Filed: August 2, 2018
• Petitioner(s): ZTE (USA), Inc.
• Patent Owner(s): Fractus SA.
• Challenged Claims: 5-13

2. Patent Overview

• Title: Multilevel Antennas
• Brief Description: The ’432 patent discloses multilevel antennas for portable devices designed to operate in multiple frequency bands while maintaining a small size. The technology is based on using repeating geometric elements, such as polygons, grouped to form a larger overall structure with at least two levels of detail, creating empty spaces that allow for longer, more winding current paths.

3. Grounds for Unpatentability

Ground 1: Obviousness over Misra I in view of Misra II - Claims 5-13 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, which describes a Concentric Microstrip Triangular-Ring Antenna (CMTRA), discloses the core limitations of a multi-band antenna with a "multilevel structure." Misra I's antenna is comprised of multiple levels of detail (three concentric triangular rings), which are in turn composed of four-sided polygons ("geometric elements"). These elements create empty spaces that provide a circuitous current path, and the different levels correspond to different frequency bands. To the extent Misra I does not explicitly teach "electromagnetically coupled" elements, Petitioner asserted that Misra II, by the same authors, remedies this by disclosing an "electromagnetically coupled concentric microstrip" antenna. For dependent claims, Petitioner contended that the combination teaches that the overall shape of the antenna is a design choice. For example, while Misra I's overall triangular structure has fewer sides (3) than its constituent elements (4), a Person Having Ordinary Skill in the Art (PHOSITA) would understand that other shapes (e.g., pentagonal) could be used where the perimeter has a greater number of sides, as recited in certain dependent claims.
  • Motivation to Combine: A PHOSITA seeking to design a small, multiband antenna would combine Misra I and Misra II. Both references are by the same authors, address the same technical problem, and disclose similar concentric-ring antenna structures (triangular and square, respectively). Combining them would have been a matter of substituting known elements and design principles to optimize antenna performance.
  • Expectation of Success: The combination involved applying known configurations from highly related prior art, providing a PHOSITA with a high expectation of success in achieving a functional multiband antenna.

Ground 2: Obviousness over Grangeat - Claims 5-13 are obvious over Grangeat.

• Prior Art Relied Upon: Grangeat (Patent 6,133,879).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Grangeat, which discloses a "multifrequency microstrip antenna" for portable telephones, renders the challenged claims obvious on its own. Grangeat teaches a conductive radiating element with a multilevel structure comprising multiple "zones" (geometric elements) that provide operation at three distinct frequency bands. The arrangement of these zones defines slots that create empty spaces and a circuitous current path for the antenna. Petitioner asserted that Grangeat's antenna meets the limitations of the dependent claims as well. For example, the perimeter of the overall structure in Grangeat's Figure 5 has a different (and greater) number of sides than the four-sided polygonal geometric elements that compose it. Further, Grangeat teaches its antenna can be fabricated as a copper sheet on a printed circuit board for use in a portable device, meeting the limitations of claims 5 and 6.

4. Key Claim Construction Positions

• "multilevel structure": This was the central term of dispute. Petitioner proposed a detailed construction requiring "a structure for an antenna useable at multiple frequency bands with at least two levels of detail," where levels are composed of polygons of the same type. Crucially, the construction required that most (>75%) of the polygons are clearly visible and that most (>75%) have an area of contact with other elements that is less than 50% of their perimeter or area. Petitioner stated it would apply this narrower construction for the purposes of the petition.
• "geometric elements": Petitioner proposed this term be construed as "a closed plane figure bounded by straight lines or a closed plane bound by a circle or an ellipse."

5. Arguments Regarding Discretionary Denial

• Petitioner argued that the grounds presented were not the same or substantially the same as those previously considered by the USPTO during prosecution or reexamination, implicitly arguing against denial under 35 U.S.C. §325(d).
• Specifically, Petitioner noted that the combination of Misra I and Misra II was never considered for the challenged claims 5-13.
• While Grangeat was previously before the office in an ex parte reexamination, Petitioner contended that the prior submission lacked the necessary particulars and expert testimony regarding the antenna's characteristics. Therefore, the PTO did not perform a substantive patentability analysis on the merits of a ground based on Grangeat, and the current petition presented new arguments and evidence.

6. Relief Requested

• Petitioner requested institution of an inter partes review and cancellation of claims 5-13 of the ’432 patent as unpatentable.