Design of a quad-band multipolarized monopulse Cassegrain antenna

The aim of this paper is to develop a quad-band, multifunctional monopulse Cassegrain antenna suitable for integration into aircraft for deep space exploration. This design addresses the common limitations of space and weight in such missions. The antenna achieves multiplexing of the X1, X2, X3, and Ka bands using a 5-horn array feed. The X3-band monopulse function is realized through four square horns positioned around the array, with horizontal polarization for the X1 and X3 bands and vertical polarization for the X2 and Ka bands. Measurement results indicate that the VSWR is below 1.5 for the X2, X3, and Ka bands, below 1.6 for the X1 band, and below 1.6 for the X3 differential port. The measured gain exceeds 38.9 dB for the X1 band, 40 dB for the X2 band, 41.1 dB for the X3 sum port, 38.1 dB for the X3 azimuthal-differential port, 38.4 dB for the X3 elevation-differential port, and 51.2 dB for the Ka band. This antenna is well-suited for aircraft engaged in deep space exploration missions.