Axially Displaced Ellipse Reflector Antenna Design and Analysis using Multilevel Fast Multipole Accelerated Method of Moments Solution of Electric Field Integral Equation

摘要

Ring-focus dual reflector antennas have recently been employed in various satellite communication applications because of their higher gain and compactness as compared to the conventional Cassegrain or Gregorian counterparts. Innovative and efficient analytical modelling, full-wave analysis and testing of a ring-focus dual reflector antenna based on axially displaced ellipse (ADE) configuration are reported in the present contribution. The geometrical design of the dual reflector system has been achieved with the help of modified conic section formulations. An indigenously developed multilevel fast multipole method accelerated method of moments solution of electric field integral equation for open perfect electrically conducting objects has been applied to predict the RF performance of the designed ring-focus geometry. The surface current distribution of a ring focus subreflector has been investigated and compared with that of a classical Cassegrain subreflector. Such a distinct nature of current distribution of a ring focus subreflector has potential possible applications in antenna gain enhancement and sidelobe reduction techniques. Finally, analytical results are compared with measurements for a 35 wavelength diameter reflector antenna where a very close agreement was observed. Measurement results clearly indicate that ADE reflector antennas make achieving high gain possible.