Modelling of a microstrip antenna on a finite ground plane using the expansion wave concept and the aperture integral equation formulation

A microstrip antenna located on a finite ground plane has been analysed. The calculation is split into several steps. In the first step, the microstrip antenna on an infinite ground plane is analysed using the moment method. In the next step, the radiation pattern is calculated using ray tracing techniques. The fields in the layered structure are expanded into a finite number of expansion waves. The expansion waves propagate up to the edges of the finite ground plane, where they diffract. Diffraction coefficients for these waves are calculated using a formulation based on the aperture integral equation. The experimental results are in good agreement with the proposed model.