Scattering matrix of dielectric resonator coupled with two microstrip lines

A lumped equivalent circuit is proposed to model the coupling of a dielectric resonator with two microstrip lines terminated by any impedance. A three-dimensional finite-element method is used to determine the resonant frequency, quality factor, and coupling coefficients as functions of the electromagnetic parameters of the structure. Scattering parameters are computed. Methods are presented to evaluate these coefficients from a field analysis. They are shown to give good agreement between computed and experimental results.>