Advanced multimode cavity filter design using source/load-resonance circuit cross couplings

Several degenerate resonances of one cavity are simultaneously coupled to the same interface (waveguide) port that represents source or load of the network. This new method extends significantly the design possibilities for multimode cavity filters-odd-order true elliptic function designs are now possible along with other conspicuous design variants by novel coupling structures. Experimental verification is provided for this approach by a three-order elliptic function filter realized with one triple-mode cavity.<>