High Selective Ultra-Wideband (UWB) Bandpass Filter with Wideband Harmonic Suppression

This paper presents a novel ultra-wideband (UWB) bandpass filter (BPF) with wideband harmonic suppression and high selectivity on liquid crystal polymer (LCP) substrate. In the design, radial stubs are adopted to suppress out-of-band harmonic response and increase selectivity. A 10-pole proposed prototype with 120.6% fractional bandwidth is designed with equivalent circuit and full-wave simulator. The designed UWB BPF is fabricated on organic liquid crystal polymer (LCP) substrate and measured using vector network analyzer. Good agreement between simulation and measurement results is presented. Measurement results show that the fabricated filter exhibits ultra wide passband from 2.7 GHz to 10.9 GHz, a low insertion losses of 0.43 dB at 6.8 GHz, wideband harmonic suppression and high selectivity.