Stacked gap-coupled multi-resonator rectangular microstrip antennas

Various stacked combinations of multiple rectangular patches on thick air dielectric substrates are presented. In all these configurations, only one rectangular patch at the bottom layer is fed with coaxial line and the other patches are parasitically coupled. The parametric study has been carried out using method of moments based IE3D software, and final optimized configurations are given for broad bandwidth and high gain. The configuration with three rectangular patches stacked on a single fed patch yielded bandwidth of 830 MHz (25.7%) with more than 10 dB gain within the bandwidth. Higher gain is achieved when three patches are stacked on the three gap-coupled rectangular patches.