Abstract
This paper proposes extending the forward-scattering based Tabulated Interaction Method (TIM) [1] for computing electromagnetic wave propagation over terrain profiles to one incorporating back-scattering. The proposed method uses a common set of basis functions in conjunction with a "matching technique" to compress the original linear system to a reduced system containing much fewer unknowns and therefore provides a very efficient and accurate method. The original TIM [1] is shown to be a special case of the proposed method whereby the lower triangular portion of the reduced system is retained and solved. The proposed method is compared with the recently proposed Characteristic Basis Function Method (CBFM) [2], [3] with which it shares several features. The complexity and numerical analysis demonstrates that the proposed method has an extremely low computational complexity and storage.