Novel broadband suspended substrate stripline filter using dual-mode resonators

A novel broadband suspended substrate filter is proposed and implemented using dual-mode resonator aiming at transmitting the signals in the passband of 10–18GHz. It is composed of two quarter-wavelength resonators and inductor. The inductor is a short-circuited stub. 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 10dB, and the insertion loss is less than 1.9dB.