A Miniaturized Quasi-Elliptic BPF with High Selectivity Based on Combining CPWs and CSRR in a Single Dual-Mode SIW Cavity

摘要

A fifth-order bandpass filter with quasi-elliptic response based on combining two coplanar waveguides (CPWs) and a complementary open loop resonator (CSRR) in a single dual-mode substrate integrated waveguide (SIW) cavity is proposed. The presented filter has advantages of compact size and high selectivity because the CPWs and CSRR are etched on the top metal surface of dual-mode SIW cavity and multiple transmission zeros (TZs) are produced. The TZs are realized by the multipath energy flow and electric and magnetic mixed coupling in the proposed structure. A prototype filter with center frequency of 5.8 GHz is designed, fabricated and measured. The measured results agree with the simulated ones.