Scattering matrix approach for the design of microwave filters

A synthesis procedure, based on a distributed parameter model, for the desi gn of microwave Biters is presented in this paper. The frequency response o f the Biter is described in terms of the characteristic polynomial T-21 = S -11/S-21 where S-11 and S-21 are the scattering parameters of the filter. S tarting from the desired polynomial T-21, the design scheme directly yields the scattering parameters of the various junctions, which can be realized by any kind of discontinuity, The capability of synthesizing an arbitrary f requency response allows one to introduce the concept of a "pre-distorted" characteristic polynomial in order to compensate for the degradations cause d by multimodal interactions, frequency dispersion, etc. Comparison with me asured data of a Chebyshev-like eight-pole E-plane Biter confirms the valid ity of the method also in presence of losses.