Spectral Analysis of Multiport Microstrip Circuits with Active and Passive Lumped Elements

A method for the investigation of planar microstrip circuits embedded in layered media is presented. The circuit consisting of active and passive lumped elements is fed by an arbitrary number of microstrip lines. The current on the metallic structure is described by asymmetric piecewise sinusoidal basis functions. The integral equation is formulated in the spectral domain and solved with the method of moments. The verification of the computed results is discussed.