Design method of four‐reflector type beam waveguide feeds

Abstract

AbstractWe describe a design method for four‐reflector type beam waveguide feeds composed of a conical horn and four reflectors which are widely used for the first‐stage radiation system of earth station antennas in satellite communication. The relational equation between the design parameters is derived based on beam‐mode expansion and we specify the independent design parameters. We derive the relation between the design parameters and such performance characteristics as spillover loss, cross‐polarization component and frequency. As design criteria (I) we minimize the cross‐polarization component on the condition of maintaining the spillover loss within a tolerable level, and (II) we minimize the spillover loss on the condition of maintaining the cross‐polarization component with a tolerable level. In determining the size of reflectors under prescribed mechanical constraints we establish that the design parameters governing the size of the conical horn and the shape of reflectors can be determined uniquely. Examples of application of this design method are presented to show the effect of the design parameters and to increase the design efficiency.