Interplay between the ray and mode effects in electromagnetic behavior of small-size hemielliptic dielectric lenses

Focusing and resonance properties of two-dimensional (2-D) small-size hemielliptic lenses made of different materials are studied numerically in order to estimate the influence of internal reflections on the radiation characteristics of dielectric lens antennas (DLA). Accuracy of in-house made algorithms based on combination of geometrical and physical optics (GO, PO) and FDTD in the analysis of optical and modal effects in the behavior of such lenses is tested by comparison with the exact solution obtained using the Muller boundary integral equations (MBIE). The range of applicability for the approaches is discussed.