A compact wideband filter designed on single one-third equilateral triangular cavity

A one-third triangular resonator with two electric walls and two virtual magnetic walls is used to realize a compact wideband bandpass filter. This structure is fulfilled by taking out an isosceles or equilateral triangular resonator of substrate integrated waveguide (SIW) version and therefore, it is called one-third-mode substrate integrated resonator (OTMSIR). Based on one single cavity, a quadruple-mode technique is used to design a compact filter by adding an elliptical metallic via-hole and using detected ground structure (DGS). Finally, a 12.6 GHz bandwidth planar quadruple-mode filter is fabricated and tested. The measured results agree well with the simulated ones. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1993–1996, 2016