Quasi-ray Gaussian beam algorithm for time-harmonic two-dimensional scattering by moderately rough interfaces

Gabor-based Gaussian beam (GB) algorithms, in conjunction with the complex source point (CSP) method for generating beam-like wave objects, have found application in a variety of high-frequency wave propagation and diffractio n scenarios. Of special interest for efficient numerical implementation is the noncollimated narrow-waisted species of GB, which reduces the computati onally intensive complex ray tracing for collimated GB propagation and scat tering to quasi-real ray tracing, without the failure of strictly real ray field algorithms in caustic and other transition regions. The Gabor-based n arrow-waisted CSP-GB method has been applied previously [1]-[3] to two-dime nsional (2-D) propagation from extended nonfocused and focused aperture dis tributions through arbitrarily curved 2-D layered environments. In this 2-D study, the method is applied to aperture-excited field scattering from, an d transmission through, a moderately rough interface between two dielectric media. It is shown that the algorithm produces accurate and computationall y efficient solutions for this complex propagation environment, over a rang e of calibrated combinations of the problem parameters. One of the potentia l uses of the algorithm is as an efficient forward solver for inverse probl ems concerned with profile and object reconstruction [4].