A generalized theory of tapered transmission line matching transformers and asymmetric couplers supporting non-TEM modes

A general Fourier transform pair for the analysis and synthesis of tapered transmission lines supporting a non-TEM (transverse electromagnetic) mode is presented. The Fourier transform pair first pointed out by F. Bolinder (1950) for TEM lines is shown to be a special case of the present transform pair. The transform pair is mathematically rigorous and simple enough to implement on a desktop computer for the design of dispersive transmission line tapers. A step-by-step synthesis method is described for exact designs of matching transformers and asymmetric couplers. The theory is verified with the design of two Ka-band finline tapers and a C-band microstrip coupler.<
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