Multifrequency broadband polarized horn antenna

A multifrequency, broadband horn antenna comprising

• a ring loaded corrugated conical horn having a large diameter end and a small diameter end, said small diameter end having a common axis with said large diameter end and said conical horn being open at the large diameter end thereof, and having at least one diametrically opposed pair of ports at a position near the small diameter end for feeding a colinear signal of low frequency, and
• a multiplexer for simultaneously feeding additional colinear frequency signals spaced over multiple octaves into said conical horn through said small diameter end, said multiplexer comprising a waveguide having a plurality of ports, and means for fixing standing waves of signals fed into said waveguide, at least one port for each additional colinear frequency signal, said ports being spaced along said waveguide with the port for the highest frequency signal at the end furthest from said small diameter end, and the ports for the intermediate frequency signals spaced between the end of the waveguide and the small diameter end, each intermediate colinear signal port having connected thereto a low pass filter to reject frequencies above the frequency fed into the port through the filter, and at least one port for a lower frequency than the highest being at a position corresponding to the standing wave null of a higher frequency for isolation from signals of the higher frequency.