Transmit-receive hybrid having polarization filter

1,090,860. Waveguide junctions. ALBISWERK ZURICH A.G. Nov. 6, 1964 [Nov. 8, 1963], No. 45254/64. Addition to 1,020,763. Heading H1W. In the waveguide assembly of the parent Specification, in which polarized radiation is fed to an antenna, and in which the assembly includes a monitoring waveguide section which is arranged with its longitudinal axis perpendicular to the direction of propagation and at a given small angle # to the plane of polarization, so as to extract a predetermined small portion of the radiation, the remainder of the radiation is fed to the antenna via means which rotates the plane of polarization through #/2, such that radiation reflected back from the antenna arrives at the monitoring section polarized in a plane perpendicular to the latter's axis, whereby transfer of reflected energy to the monitoring section is prevented. In a microwave transmission assembly for distance measuring, a cavity resonator feeds into a rectangular waveguide 3 which is joined by way of a junction piece 2 and circular waveguides 1, 5 (Fig. 2, not shown) to an antenna, a rectangular waveguide monitoring section 4 being connected adjacent the junction piece at an angle # to the minor axis of the guide 3, as shown. The circular waveguide 5 includes a fin (shown by a broken line) to rotate the plane of polarization through #/2, whereby reflected radiation is polarized at an angle # and is rejected by the monitoring section, which accepts a small portion of the energy fed to the antenna from the resonator, and substantially the whole of the radiation, polarized in a perpendicular plane, which is received by the antenna from a like assembly located at the distant point.