Systematic network model generation for linear reciprocal microwave multiports

This article describes the synthesis of compact lumped element equivalent circuits for linear reciprocal multiports using a multiport generalized Foster representation. The multiport microwave device under investigation is a four-port coupled line coupler. The S-parameters are obtained from measurement. By means of system identification the poles and residues of the transfer function are extracted. The synthesized model provides a compact lumped element circuit for network analysis tools.