Resonance Frequency Calculation of a Multilayer and Multipatch Spherical Microstrip Structure Using a Hybrid Technique

This communication offers a rigorous analysis of the resonance frequency problem of a spherical microstrip structure mounted on a multilayer, dielectric-coated metallic sphere, with an electrically small radius. The structure consists of single or multiple metallic patches with arbitrary shapes. A full-wave analysis is employed with the use of proposed hybrid approach, combining the finite-difference technique with a spectral domain approach (SDA). In this approach, the finite-difference technique is applied in a cavity model to determine the current basis functions on the patch of an arbitrary shape. Then, the SDA is used to calculate the complex resonance frequencies of the structure. The numerical results concerning modes suitable for antenna applications are calculated. The presented results are verified by comparing them with the ones obtained from commercial software.