Abstract: An arrangement is disclosed for connecting two identical electromagnetic wave guides with rectangular cross-section, which serve to transmit linearly polarised electromagnetic waves and the rectangular hollow spaces of which are twisted with respect to one another in such a way that their corresponding axes run at right angles to one another. Between the two wave guides a connecting element is arranged, by means of which a low-reflection rotation of the polarisation plane of the waves to be transmitted takes place from the polarisation plane of one wave guide into the polarisation plane of the other wave guide orthogonal thereto.

Abstract: A polarizer for two different frequency bands is described for exciting an antenna with a parabolic reflector. The polarizer has a waveguide section capable of carrying in each frequency band two mutually perpendicularly linearly polarized waves. For each frequency band, two waveguides having a rectangular cross-section are connected to the waveguide section separate from each other and mutually offset in the axial direction of the waveguide section. A respective waveguide is connected directly to the waveguide section for each polarization direction of the lower frequency band, whereas for the upper frequency band—from a connecting point (11, 12) on—each of the two waveguides is subdivided into two branches (18, 19, 20, 21) with each having identical rectangular cross-section. The respective branches terminate on the waveguide section at mutually opposing locations which are circumferentially offset relative to each other by 90° for the two polarization directions.

Abstract: A polarizer for two different frequency bands for exciting an antenna with a parabolic reflector has a waveguide section capable of carrying in each frequency band two mutually perpendicularly linearly polarized waves. For each frequency band, there are connected to the waveguide section, separate from each other and mutually offset in the axial direction of the waveguide section, two waveguides having a rectangular cross-section. For the lower frequency band, for each polarization direction, a respective waveguide is connected directly to the waveguide section. For the higher frequency band, starting at a connecting point, each of the two waveguides is subdivided into two waveguide branches with identical rectangular cross-sections, with the branches terminating at two opposing locations of the waveguide section. The locations, where the branches for the two different polarization directions terminate on the waveguide section, are circumferentially offset relative to each other by 90.degree..

Abstract: An excitation system is indicated for an antenna with a parabolic reflector (1) and a dielectric radiator (3) which is attached to the end of a hollow conductor used to guide electromagnetic waves, and is located in the center of the reflector (1) and has a metallized end face designed as a subreflector. The reflector (1) is designed as a rectangular strip forming a sector antenna which has a parabolic curve in the direction of its long axis (A). The end face of the radiator (3) has four partial faces (8, 9, 10, 11) which form pairs and are arranged with respect to the central axis of the hollow waveguide (2) so that each pair of partial faces extends approximately at a right angle to the other pair of partial faces, the partial faces of each pair being of equal size. The two partial faces (8, 9) extending in the direction of the long axis of reflector (1) are large in relation to the two partial faces (10, 11) extending crosswise thereto.

Abstract: A device is indicated for covering the aperture of an antenna having a parabolic reflector and an exciter. The cover is made of a rigid material. The cover includes a shield ring connected to the reflector and a plastic cover shaped like a flat or obtuse cone having a conical portion which closes the open end of the reflector. The wall of the conical portion of the cover forms an angle between 4.degree. and 6.degree. with a plane that is at a right angle to the axis of the shield ring.