Adaptive prototype for fixed length and dual-band waveguide H-plane filters

An algorithm for the design of waveguide filters with prescribed length is presented. The technique is based on the concept of adaptive prototype, providing a one-to-one correspondence between the circuit and the physical structure, as for classical Cohn´s direct-coupled cavity filters. In addition, two fixed length filters can be joined together to construct a dual-band filter. Examples of application of the method are discussed.