Design tool for high-performance rotationally symmetric reflector antennas

In this paper, we present an efficient higher-order BoR-MoM in which the unknown surface current is discretized using hierarchical Legendre basis functions, that are adapted to the circular symmetric geometry. Furthermore, the shape of the generatrix is represented by up to 4th order curvilinear line segments that approximates curved surfaces with high accuracy. The combination of a higher-order polynomial current approximation and the smooth geometry implies that the number of unknowns is reduced to approximately 4 per wavelength, i.e., approximately a four-fold reduction compared to the low-order case. This reduction leads to a dramatic speedup such that a full-wave analysis of typical rotationally symmetric antennas can be accomplished in 1-2 seconds on a laptop. The new higher-order BoR-MoM has been rigorously combined with a mode-matching tool for circular horns which implies that complex feeds, such as corrugated feeders, can also be analyzed in a couple of seconds. Furthermore, this hybrid mode-matching/higher-order MoM analysis engine is integrated in an optimization framework for rotationally symmetric reflectors and feeders. This design tool integrates all the required functionality in a single tool which is demonstrated by a design example of a compact antenna with a very small aperture.