The multiple feed antenna comprises a primary focussing element and at least two feeds The feeds are spaced from each other and have different characteristics such as different frequency bands The focussing element is moved such that its focal point coincides individually with the feeds The focussing element may be designed to be offset with respect to its focal axis In this manner, the antenna may have a common aperture and common boresight for each of the feeds

Multiple feed antenna

A fixed feed dual reflector scanning antenna system 10 having a low moment of inertia is disclosed herein. The inventive dual reflector antenna system 10 includes an antenna feed structure 16 for emitting electromagnetic radiation. The antenna system 10 further includes a subreflector 12 for redirecting the emitted radiation. The subreflector 12 is intersected by a subreflector longitudinal axis Ls at a rotation point proximate a vertex 20 of the subreflector 12. A main antenna reflector 14 circumscribing a main longitudinal axis Lm projects radiation redirected by the subreflector 12 as an antenna beam. A mechanical arrangement 22 rotates the subreflector 12 about the rotation point so as to vary the angular orientation between the subreflector longitudinal axis Ls and the main longitudinal axis Lm. In this manner the antenna beam is scanned relative to the main longitudinal axis Lm.

Dual reflector scanning antenna system

A multiband satellite communication antenna system includes a primary reflector and one or more movable subreflectors. A system with one subreflector operates at a first band when the subreflector is in a deployed position and reflects energy between a first feed and the primary antenna. When the subreflector is at a second, stowed, position, the primary reflector operates directly into a second feed. A communication antenna system with two subreflectors can operate at three bands under the conditions of having either both subreflectors stowed; the first subreflector deployed and the second subreflector stowed; or both subreflectors deployed.

Multiband satellite communication antenna system with retractable subreflector

A mission-flexibility antenna includes a reflector and at least a first source and a second source of radiofrequency signals, which sources are arranged in front of the reflector, the reflector having a focal point and each source having a phase centre, and wherein the sources are independent, fixed and connected to separate radiofrequency feed systems defining different and predefined polarization and/or operating frequency characteristics, and in that it additionally includes means of displacement and orientation of the reflector from a first position in which the focal point of the reflector is placed at the phase centre of the first source to a second position in which the focal point of the reflector is placed at the phase centre of the second source.

Mission-Flexibility Antenna, Satellite Including Such an Antenna and Method for Controlling the Change of Mission of Such an Antenna

A microwave antenna has a circularly symmetrical reflector made of a material having a liquid phase and a solid phase, with the reflector being obtained by centrifuging the material while in its liquid phase and then allowing it to pass into its solid phase. This results in a convex paraboloidal reflector face having a very high degree of surface accuracy. When housed inside a microwave absorbing ring connecting the reflector face to a microwave-transparent window and used with a suitable source held at a predetermined focus position between the reflector and the window by means of microwave absorbent triangular struts, the antenna demonstrates improved radio and mechanical properties. Alternately, the centrifugally cast convex paraboloidal reflector may be used as the main reflector in a hybrid Cassegrain optical system in which the subreflector has a "conformed" non-paraboloidal surface that is machined from a solid piece of material. This results in an antenna that is easy to manufacture, and yet has much of the improved radio performance associated with the use of "conformed" surfaces for both reflectors. By also using a "conformed" lens at the aperture of the source, performance of such a hybrid system is further enhanced.

Masakazu Smoot Katow

Papers

Multi-feed cone cassegrain antenna