Reflector Rim and Feed Considerations for Simple Switched-Beam Antenna Prototype

A simple, optimized, and easily constructed reflector-rim geometry for protyping purposes is presented as a substitute for the more cumbersome elliptical rim. The design procedure for the switched-beam antenna studied is also described. The elliptical rim shape is approximate by cutting a circular rim with six straight lines. The circular rim is first cut along two symmetrically placed parallel lines. The corners of the resulting rim are then mitered along tangent lines of the ellipse being approximated. Different designs are compared, using relative torques as estimates of wind loading. According to the simulation results, the proposed rim shape resembles an elliptical rim well in terms of beamwidth and sidelobe level. Designed to have gain equal to an elliptical reflector, the wind loading of the narrowed and mitered reflector increauses only by 5%.