Input impedance and mutual coupling of spherical rectangular microstrip patch antennas

The input and mutual impedances of rectangular microstrip patches mounted on a spherical structure are studied in the paper. The analysis approach is based on the moment method where the elements of the moment method matrix are calculated in the spectral domain. In order to avoid numerical problems a modified vector-Legendre transformation and normalized Legendre polynomials are defined and applied to the solution procedure. An approximate method is developed to calculate coupling between basis and test functions located on different patches. A laboratory model is built to test different configurations of patches and to validate the calculated results.