The US Court of Appeals for the Federal Circuit affirmed a judgment of patent invalidity on alternative grounds. The Court found that claims reciting a scientific impossibility were not indefinite because their scope was clear but were invalid for lack of enablement. Satius Holding, LLC v. Samsung Electronics Co., Ltd., Case No. 25-1446 (Fed. Cir. Oct. 1, 2026) (Moore, Lourie, Hughes, JJ.)
Satius sued Samsung for infringement of a patent directed to a communications apparatus that uses a coupler to match the characteristic impedance of air to that of a wireless transmitter and receiver. A representative claim recited “[a] communications apparatus for transmitting electric or electromagnetic signals over air.” The district court found the claims indefinite because transmitting electric signals over air is scientifically impossible. Satius appealed
The Federal Circuit first construed “transmitting electric . . . signals over air” to require transmission of signals through air in electric form, which the parties agreed was impossible. Satius argued that the limitation instead described converting electric signals into electromagnetic signals for transmission over air. The Court rejected that interpretation, explaining that transmitting signals over air differs from communicating signals to air. Adopting Satius’ interpretation would improperly rewrite the claims to add a conversion step.
Turning to indefiniteness, the Federal Circuit explained that “[i]ndefiniteness is not the same as impossibility.” A claim is indefinite only if it fails to inform skilled artisans of its scope with reasonable certainty. Here, the impossible limitation appeared in both the claims and specification, and its meaning was clear. The Federal Circuit therefore rejected the district court’s conclusion that scientific impossibility rendered the claims indefinite.
The Federal Circuit nevertheless affirmed invalidity for lack of enablement. Although the district court had not decided that issue, the Federal Circuit found it appropriate to do so because the relevant facts were undisputed and the parties had fully briefed the question. The specification must enable the full scope of the claimed invention. Because the claims expressly covered transmitting “electric or electromagnetic signals over air,” and transmitting electric signals over air is scientifically impossible, the specification could not enable the full claim scope. The claims therefore failed to meet the enablement requirement.
Practice note: A scientifically impossible claim limitation does not necessarily render a claim indefinite if its scope is reasonably certain. However, expressly claiming an impossible alternative can invalidate the claim for lack of enablement, even if other claimed alternatives are operable.
