A 4-POLE DUAL-MODE ELLIPTIC FILTER REALIZED IN CIRCULAR CAVITY WITHOUT SCREWS

A four-pole dual mode elliptic filter is realized in circular cavity w ithout screws. The desired coupling and tuning actions are achieved by using a novel arrangement consisting in the insertion of a short sect ion of inclined rectangular waveguide in the middle of the cavity body . In this way we realize dual-mode filters by using only junctions of waveguides with rectangular and circular cross sections, thus enabling a very efficient CAD of such filters. This arrangement also proves pa rticularly convenient from the manufacturing viewpoint. Measured respo nse of a breadboard channel filter operating at K u-Band shows good ag reement with theoretical simulations; a sensitivity analysis confirms the validity of the proposed design.