Cavity Resonator Filters in Shielded Quarter-Mode Substrate Integrated Waveguide Technology

The substrate integrated waveguide (SIW) technology has high performance but is relatively bulky compared to other planar technologies. Compact topologies like the quarter-mode technology aim to reduce the size of SIW components, but suffer from additional losses. A modified version of the quarter-mode resonator topology, called shielded quarter-mode, improves the performance of microwave filters with a small increase of the component area. This paper presents three different microwave filters operating at 4 GHz as an example of application for the shielded quarter-mode topology.