Volume/surface integral equation analysis of circular patch finite antennas

In this paper, a method of moment solution of a volume/surface integral equation is proposed for the analysis of circular shaped printed antennas on finite dielectric substrates. The dielectric region is meshed using tetrahedral cells, whereas the conducting regions are discretized with triangles. The basis and testing functions employed for the numerical implementation are volumetric and planar rooftops, following a full Galerkin approach. Two different novel excitation models (coaxial excitation and microstrip excitation) are presented, allowing the utilization of independent mesh cells at the fed points. With the software tool derived, microstrip patch antennas with small size dielectric substrates are investigated. Results show a small impact of the substrate size in the input impedance of the antennas. On the contrary, back-side radiation levels are more strongly affected. Results are compared with commercial software and measurements, showing good agreement for both the input impedance and the radiation patterns.