RADIATION CHARACTERISTICS OF A PLANOCONVEX LENS ANTENNA

Radiation characteristics of a piano-convex lens are studied using Mas lov's method, stressing the evaluation of an electromagnetic field aro und a caustic region when a uniform plane wave is incident axially to the flat plate side. The field expressions which are valid near a foca l region are derived in terms of finite integrals with a single variab le. As a special case, an approximate expression for a weakly focusing system is derived and compared with a corresponding expression obtain ed using Kirchhoff-Huygens principle. Agreement between them is fairly good. Numerical computation for field distribution around a focal reg ion is conducted, and the three-dimensional pictures for the results a re presented to help understand the focusing behavior of the lens.