In this letter, the design of a planar antenna compliant with FCC requirements for ultra‐wideband (UWB) transmission systems is described. With reference to a planar geometry on a dielectric substrate, the shape of the antenna is described by means of a spline‐based representation and it is determined by means of an optimization process aimed at finding the optimal descriptive parameters that allow to fit the user‐defined electrical and dimensional requirements. The reliability and effectiveness of the antenna prototype are assessed through simulations as well as experimental measurements.