Kirchhoff integrals applied to 3D simulations of radio wave propagation over complex terrain

Kirchhoff integral techniques can provide a method of calculating radio wave propagation over complex terrain with non homogeneous atmospheres. For the case of 2D propagation, it has previously been shown that, when coupled with fast Fourier transform techniques, they provide efficient propagation simulation algorithms. In this paper we consider the extension of these ideas to the provision of efficient 3D propagation simulation algorithms. It is shown that appropriate extensions to the 2D algorithms can provide efficient 3D propagation simulation algorithms.