Far-field Extrapolation of the Body-of-Revolution Parabolic Wave Equation

The parabolic wave equation (PWE) has been used extensively to model propagation in electrically large domains dominated by forward scatter. A PWE method for modeling propagation through an inhomogeneous body-of-revolution (BOR) was recently described, wherein a three-dimensional result was synthesized from a summation of independent solutions obtained with two-dimensional solvers. Far-field solutions were obtained by applying scalar diffraction theory on the axial boundary-using a cylindrical coordinate system-which required a numerical domain with a large radial extent. This paper presents an efficient method for extrapolating the field on the radial boundary into the far field, allowing for a numerical domain with a smaller radial extent, thereby increasing computational efficiency.