A NOVEL MULTILAYER DUAL-MODE SUBSTRATE INTEGRATED WAVEGUIDE COMPLEMENTARY FILTER WITH CIRCULAR AND ELLIPTIC CAVITIES (SICC AND SIEC)

A multilayer dual-mode complementary filter is developed based on substrate integrated circular and elliptic cavity (SICC and SIEC) in this paper. The filter is constructed with two different kinds of cavities, and each cavity supports two degenerate modes, which can be generated and controlled by the coupling aperture and slot located between layers. Detailed design process is introduced to synthesize an X-band dual-mode complementary filter. It not only has good performance, but also reduces the circuit size much more. Moreover, Sharp transition characteristic both in the lower and upper sidebands demonstrates high selectivity of the filter. Good agreement is obtained between the simulated and measured results of the proposed structure.