Efficient S-parameter calculation of branchline and patch couplers with the spectral domain analysis method

A spectral domain analysis method is developed for the S-parameter calculation of branchline and patch couplers. To compare the results calculated by the spectral domain analysis using the new iterative method and S-parameter extraction technique, two multiport structures have been produced and measured: a closely coupled branchline coupler connected with coupled lines and mitered bends, and a patch coupler with the same geometry. The agreement of the measured and calculated results is good with respect to the whole frequency range considered.<>