Evaluation of resonant modes in isolated dielectric resonators using a surface integral equation formulation

The numerical procedure is presented for evaluation of the resonant frequencies, radiation Q factors, and modal field patterns of isolated dielectric resonators. The method is based on the solution of the scattering problem for a dielectric body of revolution, developed by Glisson and Wilton. A dielectric resonator can be modeled as a body of revolution. The natural resonances of this body of revolution are the homogeneous solutions of the method-of-moments matrix equation. To find the electromagnetic field distribution, the equivalent modal currents on the surface of the resonator are computed by a Gaussian elimination scheme. After the modal currents are found, the modal fields at any point in space are obtained by a vector summation of the contributions due to each of the current elements. The computer-generated field plots for several modes are presented. The resonant frequencies and the Q factors have been also measured by using the network analyzer.