A novel ultra-wideband bandpass filter using defected microstrip structures

Abstract

A novel ultra-wideband (UWB) bandpass filter with compact size, improved stopband performance and wider bandwidth is presented in this paper. A new defected microstrip structures resonator (DMSR) is proposed and analyzed theoretically. In order to improve the stopband characteristics, three interdigitated parallel coupled-lines (IPCL) and two complementary split ring resonators (CSRR) are adopted. Finally, a filter prototype is fabricated and measured. The measured results show that the proposed filter achieves a bandwidth of 129% from 2.35 to 10.8 GHz. And the insertion loss is less than 0.5 dB with good return loss.