Radiation characteristics of an inhomogeneous slab using Maslov's method

Expressions for high frequency field refracted by an inhomogeneous slab are derived using the Maslov's method. Field expressions are valid in the caustic region. Maslov's method predicts the field in the caustic region by combining the simplicity of ray and generality of the transform method. Numerical computations are made for the computation of field pattern around the caustic of an inhomogeneous slab. Results are compared with those obtained by weak focusing approximation and Kirchhoff's integral. Agreement among them is fairly good.