Analysis and design of asymmetric and multiple coupled finline couplers and filters

The procedure for computing the scattering parameters of a general asymmetric and multiple coupled finline multiport is formulated in terms of the normal mode parameters of the structure. The normal mode parameters are computed by applying the spectral-domain technique to a general shielded multilayered structure. Closed-form expressions for the immittance parameters and characteristically terminated scattering parameters of the asymmetric coupled-line and three-line structures are presented. The multiport parameters of the finline structure are used to design filters, couplers, and power dividers.<>