UWB bandpass filter with novel structure and super compact size

An ultra-wideband (UWB) bandpass filter (BPF) with a novel structure and super compact size is presented. This UWB BPF is designed based on a three-line coupled resonator (TLCR), which was used as feedlines in the past. The TLCR has the characteristics of simple structure and wide passband, thus it is very suitable for compact UWB BPF design. Then, four bent stubs are loaded to improve the performance of this filter. Both the simulated and measured results show that this filter has good performance and the size is miniaturised by more than 70% compared with most reported UWB BPFs.