Computer-Aided Design of Ultra-Wideband Active Antennas by Means of a New Figure of Merit

In this letter, we address the design of a compact printed ultra-wideband antenna connected to a traveling-wave power amplifier. The antenna and the amplifier are first separately optimized by conventional means with 50 Omega terminations, which is found to result in suboptimal performance of the integrated assembly. The process is then repeated by a new design philosophy combining nonlinear harmonic-balance-based analysis with electromagnetic simulation. This approach makes use of a new figure of merit encompassing radiation and nonlinear performance, which allows the design goals to be formulated in terms of far-field performance. The proposed method leads to enhanced wideband radiation performance, strongly reducing the power density ripple across the band with respect to traditional techniques.