Alcatel

Daniel Wojtkowiak

Udo Seewig

Reimer Nagel

Karl-Heinz Reimann

Hans-Peter Quade

Stefan Rohr

In a waveguide twist having a torsion element with at least three individual parts situated adjacent to each other and rotatable around an axis of the torsion element, in which each of the individual parts has a central passage hole with a cross-section corresponding to the open cross-section of the waveguides, and in which the passage holes of the individual parts in a non-rotated condition of the torsion element are aligned with each other, a recess is formed in one face of each of the individual parts, the extent of the recess in circumferential direction corresponding to a specified angle of rotation; from the other face of the individual parts a pin extends in an axial direction; and in a mounted position of the torsion element a pin projecting from one individual part engages in the recess located in the face of the adjacent individual part.

Rotatable waveguide twist

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&mdash;from a connecting point (,) on&mdash;each of the two waveguides is subdivided into two branches (,) 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&deg; for the two polarization directions. To simplify the portion designated for the upper frequency band, the wider flat sides of the two branches (,) abut each other at each of the connecting points (,) in such a way that the front faces of the branches are aligned with each other for connection to the respective waveguide (,). In addition, one of the branches (,) of the two different polarization directions is twisted along its path about an angle of 180&deg;.

Polarizer for two different frequency bands

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.. A metal pin is located in each of the flat waveguide branches in a respective aperture thereof.

A polarizer for exciting the parabolic reflector of a directional antenna includes a profile section (7) which is formed as a waveguide and is adapted to simultaneously transmit two linearly polarized orthogonal electromagnetic waves. Two rectangular waveguides which separately guide the two electromagnetic waves are connected to the profile section (7). The end face of one of the rectangular waveguides is connected to the side wall of the profile section (7) in a radial direction, whereas the other rectangular waveguide is connected to an end face of the profile section (7). Both rectangular waveguides have an electromagnetic connection to the profile section (7) via openings, wherein a short-circuiting element (10) is disposed in the profile section (7) between the openings. Separate tuning elements are made unnecessary by locating a first transition section which is formed as a cavity (11) and has a generally rectangular cross-section, between the radially connected rectangular waveguide and the respective opening (9). Two opposing mutually aligned ribs (12, 13) which extend along the axial direction and project from the wider walls of the cavity (11) are arranged in the first transition section. In addition, a second transition section (8), which is stepped and encloses a cavity with a generally rectangular cross-section, is located between the profile section (7) and the rectangular waveguide (4). The second transition section (8) is connected to the end face of the profile section (7), wherein the end face of the rectangular waveguide is connected to the second transition section (8).

Polarizer for exciting an antenna

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.

Growing community of inventors

Neustadt, Germany

Daniel Wojtkowiak