Efficient Analysis of Scattering By Arbitrarily Shaped Thin Obstacles in Rectangular Waveguide

A moment-method based analysis of arbitrarily shaped zero-thickness obstacles in rectangular waveguide is presented. The method is discussed in two well-known formulations, and for both of them an efficient Green's functions representation is introduced. The representation is obtained by extracting suitable terms representing the asymptotic behaviour of the TE and TM part of Green's dyad. Two different sets of basis functions are then compared in terms of accuracy of the numerical results obtained: rooftops and bilinear. It is shown that the higher order set of bilinear basis function leads to spurious results, whereas no such effect appears using rooftops. A very good efficiency of the overall algorithm was observed.