A Novel Compact Self-Packaged SPDT Switchable BPFs Based on SISL Platform

This paper presents a novel compact low loss switchable bandpass filter (BPF) with self-packaging by using substrate-integrated suspended line (SISL) technology. The proposed self-packaged switchable BPFs are designed by using two kinds of suspended controllable resonators, which are smaller than a quarter-wavelength resonator and the commercial p-i-n diodes are used as the control elements. The designed method of suspended controllable resonator is investigated by using an equivalent circuit model. The center frequency of the proposed low loss SISL switchable BPF is designed at 1 GHz with 56% fractional bandwidth. The measurement results show that insertion loss is 0.9 dB of the turn ON state. Furthermore, a high isolation SISL self-packaged switchable BPF with more compact size is proposed for comparison. Measurement results show that the isolation is higher than 40 dB and insertion loss is 1.57 dB at 1 GHz, and its core circuit size is only 0.09 λ
₉
× 0.04 λ
₉
.