Diplexer for orthogonally polarized transmit/receive signalling on

Abstract

A microwave transmit/receive terminal having an antenna and associated feed for receiving vertically and horizontally polarized signals and for transmitting a horizontally polarized signal employs a diplexer to be inserted between the feed and an orthomode coupler. The diplexer is formed of a cylindrical waveguide main body, a first port of which is coupled to the feed for receiving the orthogonally polarized receive signals and for coupling thereto the (horizontally polarized) transmit signal. A second port of the main body is coupled to the orthomode coupler for receiving the horizontally polarized signal to be transmitted and for coupling thereto the vertically polarized receive signals. A rectangular waveguide section is coupled to the cylindrical waveguide main body and forms a third port for coupling the horizontally polarized received signal away from said cylindrical waveguide main body. A first filter is disposed within the cylindrical waveguide main body between the first and second ports for preventing the coupling of horizontally polarized receive signals between the first and second ports. A second filter is coupled with the rectangular waveguide section for passing the horizontally polarized receive signal while preventing the coupling of the horizontally polarized transmit signal to the third port.