A hybrid technique combining the modematching method and the geometrical theory of diffraction for edge discontinuities
Abstract
The modematching method based on the least squares approach and Rayleigh theorem has been put forward as the simple and effective method for the numerical solution of scattering problems. Although this method has a rigorous proof of convergence, it does not always give us a desirable solution for edge discontinuities due to the inevitable limitation of computer memory. The poor convergence prevents more precise computation at higher frequencies. The proposed hybrid technique combining the modematching method and the geometrical theory of diffraction (GTD) is presented to accelerate the convergence of numerical solution for the scattering problem associated with edge discontinuities. To combine GTD with the modematching method, the singular integral equation technique which provides a quasistatic approximation is introduced in the procedure of formulation. As an example to illustrate the proposed technique, we applied it to the wellknown scattering problem of an infinite plane grating. The numerical results show that the power errors are improved and are much better than those of the modematching method itself.
 Publication:

Radio Science
 Pub Date:
 December 1981
 DOI:
 10.1029/RS016i006p00983
 Bibcode:
 1981RaSc...16..983I
 Keywords:

 Electromagnetic Scattering;
 Geometrical Theory Of Diffraction;
 Interference Grating;
 Least Squares Method;
 Convergence;
 Discontinuity;
 Edges;
 Error Analysis;
 Communications and Radar