Efficient Computation of Reflector Antenna Aperture Distributions and Far Field Patterns

摘要

A computationally efficient method is presented for calculating the aperture distribution and the far field pattern of a parabolic reflector with an off-axis array feed. Idealized, uncoupled array elements and realistic, mutually coupled, circular waveguide elements are considered. Ray optics are used to determine the scalar aperture field over a rectangular grid of aperture sampling points. Two alternatively methods for performing the aperture integration required for the pattern evaluation are compared: (a) based on summation of subapertures with constant amplitude/linear phase, and (b) based on the Fast Fourier Transform (FFT) and sampling theory. Patterns obtained with this method are compared with independency computed patterns that use other approaches. The range of validity of the aperture field integration method is discussed.