PTAB

IPR2018-01455

ZTE (USA), Inc. v. Fractus, S.A.

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1. Case Identification

2. Patent Overview

  • Title: Multilevel Antennas
  • Brief Description: The ’432 patent discloses multilevel antennas for use in wireless devices. The technology centers on creating compact, multiband antennas by forming a radiating element from a plurality of "geometric elements" (e.g., polygons) that are electromagnetically coupled to form a larger structure with at least two levels of structural detail, enabling operation across multiple frequency bands.

3. Grounds for Unpatentability

Ground 1: Claims 5-13 are obvious over Misra I in view of Misra II.

  • Prior Art Relied Upon: Misra I (IEEE Transactions on Antennas and Propagations, Apr. 1998), Misra II (Microwave and Optical Technology Letters, Feb. 1996).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that Misra I teaches a concentric microstrip triangular-ring antenna (CMTRA) that is small, operates on multiple frequency bands, and comprises a multilevel structure. This structure is formed from multiple four-sided polygonal geometric elements. Petitioner argued this base reference discloses most limitations of challenged claims 5, 6, and 10. Specifically, Misra I’s antenna has a first portion (all three concentric rings) and a second, smaller portion (the inner two rings) operating at different frequencies. The overall perimeter of the Misra I antenna is a triangle (three sides), while its constituent geometric elements are four-sided, thus teaching a structure where the perimeter has a different number of sides than the elements, as required by claim 6.
    • Motivation to Combine: Petitioner contended that a person of ordinary skill in the art (POSITA) would combine Misra I and Misra II. Both references are by the same authors, address the identical problem of designing small, multiband microstrip antennas, and present different geometric configurations (triangular vs. square). This, Petitioner argued, would have motivated a POSITA to understand that the overall antenna shape is a design choice. The combination teaches that one could create other shapes, including those where the perimeter has a greater number of sides than the constituent geometric elements (as required by claims 7-9 and 11-13), such as a pentagonal ring antenna.
    • Expectation of Success: A POSITA would have had a reasonable expectation of success because combining the teachings was merely the substitution of one known antenna shape for another to achieve the predictable result of a functional multiband antenna.

Ground 2: 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 alone renders all challenged claims obvious. Grangeat discloses a multifrequency microstrip antenna for portable telephones that embodies all the key features of the invention. It teaches a multilevel structure composed of multiple geometric elements (zones) arranged to define slots, creating circuitous current paths for multiband operation. The structure includes multiple nested portions of different sizes associated with different frequency bands. Critically, Petitioner asserted that the overall perimeter of the Grangeat antenna has a greater number of sides than its constituent four-sided polygonal elements, directly teaching the limitations of claims 7-9 and 11-13. The antenna is disclosed as being formed on a printed circuit board from copper, meeting the limitation of claim 5, and for use in a portable communication device, meeting the limitation of claim 6.

4. Key Claim Construction Positions

  • "multilevel structure": Petitioner proposed this term, used in all challenged claims, be construed narrowly to mean "a structure for an antenna useable at multiple frequency bands with at least two levels of detail...composed of polygons...wherein most (i.e., more than 75%) of the polygons...are clearly visible...and...have an area of contact...that is less than 50% of the perimeter or area." Petitioner noted it was adopting this narrow construction, which the PTO previously used in an inter partes reexamination, to demonstrate obviousness even under a stringent interpretation.
  • "said second [and third] portion[s] being located substantially within the first portion": Petitioner argued this term should be construed to mean the portions are "substantially inside or enclosed by the first portion, where the first portion, the second portion, and the third portion differ in size or configuration." This construction emphasizes a physical, nested arrangement, which Petitioner contended was supported by the prior art and was narrower than the Patent Owner’s proposed construction in district court.
  • "number of sides": For claims 6-13, Petitioner argued this term should mean the "number of straight sides for geometric elements bounded by straight sides, and a large number for geometric elements bounded by a circle or an ellipse." This construction was asserted to be narrower than the Patent Owner's position that no construction was necessary.

5. Arguments Regarding Discretionary Denial

  • Petitioner argued that the grounds presented in the petition were not the same or substantially the same as those previously considered by the PTO during original prosecution or subsequent reexaminations. While some of the prior art (e.g., Grangeat, Misra II) may have been of record, Petitioner asserted they were never applied against the challenged claims in the combinations or with the specific arguments and expert testimony provided in the petition. Specifically, Petitioner noted the combination of Misra I and Misra II was never considered by the PTO for the challenged claims, and the PTO had previously declined to consider Grangeat because the prior request lacked sufficient detail, which this petition supplied via expert declaration.

6. Relief Requested

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