Multiplexing system for plural channels of electromagnetic signals

Abstract

A multiplexing system combines a plurality of electromagnetic signals to propagate along a common path, preferably a square waveguide which can be connected to an antenna feed horn of square cross section which can support both circularly and linearly polarized electromagnetic waves. The system is operative with a plurality of sets of signal channels including a first set of A-channel signals and a second set of B-channel signals. A circular polarizer connects with a first end of the waveguide. All of the A-channel signals are fed into an input port of the polarizer. The B-channel signals are coupled into the waveguide by a plurality of couplers located at positions arranged serially along the waveguide, individual one of the couplers operating at different ones of the B-channel frequencies for selectively coupling respective ones of said B-channel signals into the waveguide to propagate toward the second end of the waveguide. Each of the couplers has a rectangular waveguide and plural cylindrical cavity filters interconnecting a broad and a narrow wall of the rectangular waveguide with two contiguous walls of the square waveguide. Slotted apertures act to couple directionally the B-channel signal into the square waveguide to propagate towards the second end of the square waveguide. In one embodiment, an end of one filter contacts one waveguide, and an end of the second filter contacts the other waveguide. In a second embodiment, ends of both filters contact the square waveguide.