Computation of input impedance of printed antennas with finite size and arbitrarily shaped dielectric substrate and ground plane

The input impedances of a microstrip antenna with finite and curved substrates are calculated using the hybrid volume surface integral equation approach. The results for flat and large substrate cases are compared with the measurement as well as the method of moment solution based on the spectral domain Green's function for infinitely large ground plane. Numerical results show that the input impedance can be significantly influenced when the substrate of a patch antenna is reduced in size or curved in shape.