Compact triple-mode filter based on quarter-mode substrate integrated waveguide

This paper presents a compact triple-mode filter based on the quarter mode substrate integrated waveguide (QMSIW), which is a quadrant sector of a square waveguide resonator. Simulated electric field distributions of modes excited in QMSIW resonator are studied and they are in good agreement with theoretical predictions for the solid waveguide structure. And then, a compact triple-mode filter is designed based on the QMSIW, and its triple-mode resonator possesses three resonances in one resonator resulting in a very good filtering performance and yet retaining its compact size. This demonstrates that the QMSIW structure is an excellent candidate for compact filters design.