Design and Analysis of Ring-Focus Reflector Antenna using Method of Moments Solution of Electric Field Integral Equation

Ring-focus dual reflector antennas have been employed in various satellite communication applications because of their higher gain and geometrical compactness as compared to the conventional Cassegrain or Gregorian counterparts. In this contribution the geometrical design, full-wave analysis and testing of a ring-focus dual reflector antenna based on axially displaced ellipse (ADE) configuration are reported. The geometrical design of this dual reflector system is conceived through conic section formulations. An analytical methodology based on multilevel fast multipole method (MLFMM) accelerated method of moments (MoM) solution of surface integral equations for open perfect electrically conducting objects was developed for its RF performance prediction. The distinctive nature of surface current distributions of a ring-focus subreflector is investigated and compared with that of a Cassegrain counterpart. Finally, the developed procedure was applied to predict the performance of a 35 wavelength ADE ring focus antenna. A close agreement of predicted and measured performance was observed which proves the validity of our fast analytical procedure.