Hybrid FEM/SBR method to compute the radiation pattern from a microstrip patch antenna in a complex geometry

A previously introduced technique to compute the radiation of a microstrip patch antenna on a cylindrical body of arbitrary cross section is extended to include patch antennas mounted on complex, three-dimensional bodies. The technique involves using the finite-element method (FEM) to characterize the patch antennas, and then computing the radiation pattern with the use of the reciprocity theorem and the shooting and bouncing ray (SBR) method with edge diffraction. The validity of the calculation and the need for an extension to three dimensions is shown by comparison with measured data for a waveguide-fed trihedral. Other calculations show the effects of the external geometry on the radiation pattern of a microstrip patch antenna.