Differential substrate integrated waveguide bandpass filter with improved common-mode suppression utilising complementary split-ring resonators

摘要

A novel differential substrate integrated waveguide bandpass filter is proposed. The TE102-mode cavities arranged on the symmetrical plane could efficiently reduce the common-mode (CM) signal, meanwhile, transmitting the differential-mode signal. Additional transmission zeros have been obtained by using cross coupling in the dual-mode cavities. Moreover, by symmetrically etching complementary split-ring resonators on the bottom layer of the substrate, the CM could be suppressed whereas differential signals are not affected. To verify the above design concept, a prototype operating at 8.07 GHz has been realised and shows the desired filtering performance.