A High Efficiency Dual Frequency Multimode Monopulse Antenna Feed System

Higher order waveguide mode radiation can be incorporated into antenna feed systems to provide significant improvements in antenna performance with full polarization diversity. Multimode techniques may provide full monopulse capability from a single aperture and may simultaneously be used to broaden the monopulse reference pattern. The inherent adaptability of the basic multimode feed to dual frequency operation permits the introduction of independent dominant mode excitation at a lower frequency band. Multimode beam broadening techniques are then used to equalize the high frequency patterns with those in the low frequency band to provide a high efficiency common aperture dual frequency feed.