GB887572A - Improvements in or relating to microwave polariser arrangements - Google Patents

Abstract

887,572. Waveguides. MARCONI'S WIRELESS TELEGRAPH CO. Ltd. Sept. 16, 1960 [Jan. 11, 1960], No. 913/60. Class 40(8). Wave energy of any desired polarization is obtained by feeding the output of a generator through two mutually perpendicular, co-planar, rectangular waveguides to a common symmetrical waveguide and varying the relative phase of the energy in the two rectangular guides. In the embodiment of Fig. 3, the rectangular feeder waveguides 2, 3 are coupled to a common input 6 through an E-plane Y junction 7. One or both of the feeders 2, 3 are provided with variable phase-shifting means, e.g. 10, whereby the polarization of the waves in the output guide 1 may be varied from planar to circular through any degree of ellipticity. In a further embodiment (Fig. 5, not shown), the Y junction is replaced by a 3db. coupler. In the modification of Fig. 6, the two feeders 19, 21 are coupled at spaced points by two 3 db. couplers 14, 17 and a phase-shifter 18 variable through 180 degrees is arranged in the feeder 19 between the couplers. A further 'phase-shifter 20 in the same feeder causes a fixed phase shift of 90 degrees. With this arrangement, plane polarization in either of itwo perpendicular directions or waves rotating in either the right or left hand sense may be obtained. The output waveguide may be terminated at one end with a short-circuit and at the other with a horn comprising the primary radiator of a directional antenna.