Investigation of planar wide band quadruple-mode filter based on substrate integrated waveguide

In this paper, a quadruple-mode filter based on the substrate integrated waveguide (SIW) is investigated. The basic element of the filter is a one-third triangular resonator with two electric walls and two virtual magnetic walls. The resonator is called one-third-mode substrate integrated resonator (OTMSIR). The electric field distribution and frequencies of different modes existed in the OTMSIR are studied in order to design a quadruple-mode filter. An elliptical metallic via-hole is selected to realize the filter. A detected ground structure (DGS) is used to restrain other higher-ordered modes. Finally, the design of a 13GHz bandwidth planar quadruple-mode filter is fulfilled.