New `Planar´ waveguide cavity elliptic function filters

A new coupling method based on the utilisation of cavity transfonnation properties is established for planar waveguide (H-plane) TE10n/TEn01 mode cavity filters. This method is shown to provide the realisation of elliptic function responses by planar waveguide cavity structures, although these configurations exclusively exhibit magnetic iris couplings. Moreover, the flexibility in the design of arbitrary filter characteristics is essentially extended for this class of filters. The approach is verified by a five-pole pseudo elliptic function filter design for the millimetre wave band.