A Novel Broadband Suspended Substrate Stripline Filter using Resonators with T-shaped Open-Circuited Stubs

A novel broadband suspended substrate filter is proposed and implemented using a shielded suspended substrate stripline (SSL), aiming at transmitting the signals in the passband of 6-10 GHz. It is composed of two quarter-wavelength resonators and K-inverter. The K-inverter is composed of two short-circuited stubs. After optimization of this filter, a good bandpass behavior with ten transmission poles is theoretically realized and experimentally confirmed. Within the whole BPF passband, the return loss is found better than 14 dB, and the insertion loss is less than 1.9 dB.