THE LINEAR-PHASE TRIANGULAR FACET APPROXIMATION IN PHYSICAL OPTICS ANALYSIS OF REFLECTOR ANTENNAS

Abstract

Numerical analysis of reflector antennas uses a discrete approximation of the radiation integral. The calculation replaces the actual reflector surface with a triangular facet representation. The physical optics current is then approximated within each facet. This paper provides analytical details of the method based on the assumption of a constant magnitude and linear-phase approximation of the physical optics current. Example calculations are provided for parabolic, elliptical, and shaped subreflectors. The computed results are compared with calculations made using a constant-phase approximation. These results show that the linear-phase approximation is a significant improvement over the constant-phase approximation in that the solution converges over a larger angular region of space. This improvement can significantly reduce storage requirements and possibly execution speed. [Vol. 6, No. 2, pp. 74-85 (1991)]