An asymmetric spiral-shaped DGS optimized by genetic algorithm for wideband common-mode suppression

In this paper, we present a novel wideband common-mode suppression filter for high-speed differential signals using asymmetric spiral-shaped defected ground structure (DGS). It is optimized by using genetic algorithm (GA) to achieve a wide stopband. With the proposed method, a single asymmetric DGS, which is one of the most common structures, can provide over 10dB suppression of common-mode noise with a small differential insertion loss in a frequency range from 3.1 to 10.6GHz, covering the operating frequency band of the ultra-wideband (UWB) radio system. Our design fully shows the advantage of simplification when employing GA on DGS-based common-mode filter (CMF).