An Efficient Ring-Shaped Phase Center Calculation Method Based on a New Phase Efficiency Calculation Model

Abstract

Axially symmetric circular aperture reflector antennas fed with back-fire feeds such as the hat feed have a ring-shaped phase center. This communication presents an efficient method for calculating location of the ring-shaped phase center. First a phase efficiency calculation model (PECM) for a feed with a ring-shaped phase center is constructed. To facilitate the phase center calculation, an approximate PECM with a simpler form is also proposed. Detailed numerical results show that the model is more accurate than the existing one in the literature. Based on the proposed approximate PECM and the Newton–Raphson’s iterative method, a novel ring-shaped phase center calculation method is then developed. Phase center calculation results for two types of hat feeds show that the proposed method is accurate and efficient. Moreover, the method is easy to implement and does not rely on a good initial point.