System identification procedure in microwave structure modeling applications

This paper presents equivalent network synthesis techniques for lossy microwave structures. The band limited scattering parameters obtained by measurement or by full wave simulation was used for the network synthesis. This data could be represented by the transfer function of an equivalent circuit containing lumped elements (capacitors, inductances and resistances) and coupling elements (ideal transformers, mutual inductances and immattance inverters). The paper proposes two approaches to the equivalent network synthesis. The first one is based on the multiport Brune algorithm. The second one is based on the microwave structure model consisting of resonators and coupling elements between them. The synthesis procedure is illustrated by the example of the microstrip filter equivalent network design.