A New High-Performance Monopulse Feed with a Simple Comparator Network

Abstract

This paper presents a new high-performance five-element monopulse feed with a simple comparator network for Cassegrain reflector applications. The radiating element is a tapered dielectric rod fed by a circular waveguide which is in turn excited by a printed dipole. The center element is used for the sum pattern, while top and bottom elements are used for the elevation difference pattern, and left and right elements for the azimuth difference pattern. Out-of-phase excitation for the difference pattern is obtained by antisymmetrically placing two dipoles and combining their outputs with a power combiner. The optimally designed feed has been fabricated and measured. Measurement shows that the feed has the maximum sum pattern gain of 16.8 dBi, the difference pattern null depth of –21 dBi, and the reflection coefficient of less than –10 dB over 13.9–16.7 GHz.