Design Of Dual-Mode Waveguide Filter

The theory of designing the dual-mode waveguide filters and the method used to achieve the filter of genus elliptic function are analyzed here. Then, a four-pole generalised chebyshev filter is achieved. Mainly there are three characteristics of the dual-mode filter designed in the article: 1, This kind of filter has no coupling screws but using square-corner-cut to achieve the coupling of the two modes in one cavity; 2, The filter has no cross-coupling-iris but evanescent mode waveguide to achieve the coupling of the modes in the bordered cavities; 3 , The coaxial line is used directly to achieve the exciting of the cavity which reduce the volume of the filter greatly. The result of HFSS and experiment indicate that, the designed filter not only has small dimension and simple structure,but also is esay for modeling and emulating.In addition, because it is difficult to achieve wide-band turnable waveguide filter, a novel structure is afforded here to design a turnable dual-mode waveguide filter using seven tunable metal irises. The result of emulating in WASP-NET verifies the validity of the structure.