Lateral wave contribution to the radiation from a dielectric halfmedium

Two methods are presented for the computation of the radiation at microwave frequencies in a thin dielectric medium from a source located in a dense dielectric medium. One is based on geometrical optics and the other on physical optics. The geometrical optics approach encounters some difficulties in the evaluation of the radiation in the thin dielectric medium near grazing-incidence condition, due to excitation of a lateral wave, which is not taken in consideration by this approach. The physical optics method, which considers the lateral wave contribution, approaches this problem successfully and gives a better approximation of the radiated field near grazing. Numerical results, which compare the two methods, and experimental data are offered to validate the theoretical approach