Simple circuit model for coax-fed stacked rectangular microstrip patch antenna

A simple cavity model for a coax-fed stacked dual-patch electromagnetic-coupled microstrip antenna is presented. It is based on the cavity method and the reaction theorem, and leads to the expression of the input impedance as a function of antenna parameters and of frequency. The theoretical results agree quite well with the data of a full-wave analysis and are close enough to the experimental data. A fast computer program has been implemented on a PC