A five mode single spherical cavity microwave filter

Triple-mode degeneracy in cylindrical cavities has been successfully applied to the design of a satellite communications filter and multiplexer. A novel realization of five-mode filters using only the transverse magnetic mode or the transverse electric mode degeneracies in a single spherical cavity is presented. Experimental results obtained with a prototype five-mode quasi-elliptic function filter by exciting and controlling a five degenerate modes in a single spherical cavity with a new technique using dielectric coupling are reported. The curves measured agreed well with the theoretical values.<>