Orthomode transducer between a circular waveguide and a coaxial cable

Claim 1

An orthomode transducer, comprising: a section of a circular waveguide having a front end, a rear end, and a cylindrical wall therebetween, said wall provided with circular holes aligned along respective axes lying in two mutually perpendicular planes, each of said holes having an outer portion with a diameter which is larger than a diameter of an inner portion of the respective hole; a respective dielectric washer disposed in each of the outer portions of corresponding said holes; a respective probe extending along each of said axes into an interior of said waveguide through a respective one of the holes and supported by the respective washer, one of said probes being located close to said front end and the other of said probes being located further from said front end than said one of said probes, said probes each comprising: a first section with a diameter smaller than the remainder of the probe which is disposed in the respective washer, a second section adjacent to and connected with said first section and inwardly thereof, said second section being of a diameter larger than the diameter of said first section and defining with said inner portion of the respective hole a given coaxial impedance, a third section inwardly of and adjacent to and connected with said second section and of a diameter larger than the diameter of said second section, a fourth section inwardly of and adjacent to and connected with said third section and of a diameter greater than the diameter of said third section, and a final section inwardly of and adjacent to and connected with said fourth section and of a diameter equal to the diameter of said third section; a respective tuning screw extending through said wall diametrically opposite each of said probes; a tuning plate lying in said plane of the axis of said one of said probes close to said front end, axially spaced from said one of said probes and having a side facing away from said one of said probes; a circular disk for tuning of said other probe closing said rear end of said waveguide; and respective connectors on said waveguide for said probes and coaxial with said holes, said connectors having constant-impedance transitions which can be connected to coaxial couplings with said impedance.