by Dennis Crouch
The Federal Circuit reversed a Texas jury’s $166 million infringement verdict in Finesse Wireless LLC v. AT&T Mobility LLC, 24-1039 (Fed. Cir. Sept. 24, 2025), holding that the patentee’s contradictory and unclear expert testimony could not support the Jury’s finding of patent infringement. The case is centered on Finesse’s U.S. Patent Nos. 7,346,134 and 9,548,775, which relate to methods of reducing “intermodulation interference” in wireless communications.
Chief Judge Moore, writing for a unanimous panel, emphasized that when a patentee’s infringement case rests on “self-contradictory testimony” from its expert, courts “may conclude the evidence is insufficient” to satisfy the burden of proof. But in this case, the panel didn’t just note the possibility of insufficient evidence – it actually applied the rule against the patentee. After analyzing Dr. Wells’s contradictions, the opinion held: “This sort of confusing change of course is not sufficient to support the jury verdict.”
This decision underscores the Federal Circuit’s escalating demands on expert testimony in patent cases. It shows up at two levels: (1) parties must marshal “their” experts to walk the jury through virtually every technical or patent‐law issue; and (2) the expert’s testimony must be internally consistent, tightly tied to the record, and conveyed with particularized precision. I’ve written on this new hurdle that is typically focused on patentee-presentations. See Federal Circuit Tightens Expert Testimony Standards in Trudell, Patently-O (Feb. 2025); Throwing Out the Jury: How the Federal Circuit’s ‘Particularized Testimony’ Rule Further Threatens the Doctrine of Equivalents, Patently-O, (May 2025); Wilco v. Weeks Marine: When Expert Disagreements Don’t Create Genuine Disputes of Material Fact, Patently-O (Aug. 2025); and The Remedies Remedy is Almost Complete: EcoFactor v. Google, Patently-O (May 2025).
The Seventh Amendment and Judgment as a Matter of Law: Patent infringement determinations are covered by the Seventh Amendment's guarantee of trial by jury in civil cases. However, this constitutional protection does not prevent courts from granting judgment as a matter of law (JMOL) (AKA Judgment Notwithstanding the Verdict) when the evidence is insufficient to support the verdict. Under Federal Rule of Civil Procedure 50, courts may grant JMOL if "a reasonable jury would not have a legally sufficient evidentiary basis to find for the party on that issue." The Seventh Amendment prohibits "re-examin[ing]" any fact tried by the jury, other "than according to the rules of the common law." But, at common law in 1791, judges had authority to set aside verdicts that lacked a legally sufficient evidentiary basis. JMOL is the modern codification of that same authority.
In this case, Dr. Jonathan Wells, Finesse’s infringement expert, provided testimony that the court characterized as “confusing and unclear” regarding which accused system components corresponded to claimed patent limitations. For the ‘134 patent claims, Dr. Wells initially mapped “interference generating signals” to a “modeled PIM path” but then acknowledged on cross-examination that this path could not be sampled by the accused radio’s receiver because it is generated downstream after sampling occurs. When pressed, Dr. Wells “pivoted” to reference different signal inputs (x1 and x2) but “never clarified he meant x1 and x2 when he was saying DL(TX) reference and modeled PIM path.” Similarly, for the ‘775 patent claims requiring seven specific multiplications, Dr. Wells identified only three distinct multiplications in the accused system and failed to explain how these mapped to the seven claimed operations.
Proving Patent Infringement: Patent infringement requires proving that the accused product or method meets each element of at least one patent claim, either literally or under the doctrine of equivalents. 35 U.S.C. § 271(a). In complex technology cases, patentees typically rely on expert witnesses to explain how accused products satisfy claim limitations. The burden of proof rests on the patentee to show infringement by a preponderance of the evidence.
For the ‘134 patent, the central problem was Dr. Wells’ inability to clearly identify which signals in the accused Nokia radios constituted the claimed “signals of interest” and “interference generating signals.” The claims require over-sampling “a passband of received signals” that includes both types of signals. Dr. Wells consistently testified that the “modeled PIM path” represented the interference generating signals, but defendants’ cross-examination revealed this path is generated after sampling occurs, making it impossible for the receiver to sample these signals as required by the claims. When Dr. Wells attempted to salvage his testimony by referencing signal inputs x1 and x2, he failed to clearly map these inputs to the claimed signal types, instead continuing to reference the downstream modeled PIM path.
This is a case where an excellent cross examination caused the testimony to crumble. The expert report had opined that specific system components met the claim constructions, but the testimony revealed fundamental gaps in the analysis.
The ‘775 patent analysis has to do with precise claim limitation mapping by the expert witness. The claims require “multiplying and filtering” three signals in seven specific multiplications. Dr. Wells testified the accused radios perform these operations based on a Nokia technical document, but the document showed only three distinct multiplications (not all seven). That was not enough. At oral argument, Finesse attempted to argue the accused radios actually perform ten multiplications (not just seven), but that argument left a big gap because it failed to identify the specific multiplications required by the claims.
The decision continues a notable trend of Federal Circuit reversals of patent jury verdicts. In 2024 and 2025, the court has shown particular skepticism toward jury verdicts that rely upon shaky expert testimony. The court’s demanding approach reflects broader concerns about the quality of expert testimony in patent litigation and the risk that unclear or misleading expert opinions might mislead juries in complex technology cases.