Finite-difference implementation of semiasymptotic method for quasiperiodic impedance plane

Phenomena of coupling of wave beam and surface wave at impedance plane with spatially oscillating parameters are theoretically considered. Used method is asymptotic accordingly smoothness parameter and is numerical accordingly perturbation amplitudes. It combines advantages of the asymptotic and numeric methods in cases of quasiperiodic structures with large number of "periods". Obtained coupling coefficients are compared with known asymptotic expressions. Errors of finite-difference approximation of integral operator are analyzed.