Mitsubishi Denki Kabushiki Kaisha

Nippon Telegraph and Telephone Public Corporation

Shinichi Betsudan

Motoo Mizusawa

Shigeru Sato

Takashi Katagi

Katsuhiko Aoki

Shuji Urasaki

Tadashi Takano

Sigeru Sato

Masanao Iimori

Chikao Kinoshita

An antenna system having a main reflector, a sub-reflector, and a plurality of horns for radiating different frequencies includes a beam waveguide system which cancels cross polarization otherwise inherent in the system. If the antenna system uses a non-rotationally-symmetric sub-reflector the cross polarization caused thereby is cancelled by the beam waveguide system having at least two focusing reflectors and selected parameters. Alternatively the beam waveguide system can be used with a rotationally symmetric and stationary sub-reflector by being positioned to reflect said beam on the axis of the main reflector. Either the horns or the focusing reflectors may be rotatably switched, the other group being stationary.

Antenna system with plural horn feeds

A subreflector and reflectors in a primary radiation system, these constituting an offset dual-reflector aerial, are subjected to the so-called reflector-surface shaping. The main reflector is formed as a part of a revolutional paraboloid, and is a combination of a number of congruent reflector-segments. With such an arrangement, the manufacturing cost of a large-sized main reflector is reduced. The production error, and the aerial gain reduction and the deterioration of a wide-angle directivity due to the production error are minimized.

Offset dual-reflector aerial having tapered reflector segments in main

An aerial system (antenna system) comprises

Cassegrainian antenna with beam waveguide feed to reduce spillover

A reflector antenna used for radar, etc, has a subreflector so as to give a relatively large aperture diameter for a primary radiator, and to decrease the effect of the outer atmosphere. A subreflector having a different curvature in a vertical plane than a curvature in a horizontal plane is provided whereby an antenna having a different beam width in the vertical plane to that in the horizontal plane is provided even though a primary radiator having a rotationally symmetrical beam is employed.

Reflector antenna having main and subreflector of diverse curvature

Growing community of inventors

Amagasaki, Japan

Shinichi Betsudan