Wiggly Parallel-Coupled Line Design by Using Multiobjective Evolutionay Algorithm

This letter proposes a new optimization technique for wiggly parallel-coupled line (PCL) structure design. Compared with other existing wiggly PCL design approach, our proposed technique does not require complicated math formula derivation and is able to consider several performance indexes simultaneously. We use our technique to design a compact ultra-wideband (UWB) microstrip bandpass filter (BPF) at 3.1–10.6 GHz for achieving low passband insertion loss and good linearity, and satisfying out-of-band rejection. This filter can be used in indoor and hand-held UWB systems.