Abstract: A composite antenna reflector architecture for improving beam-to-beam isolation in a multi-spot illuminated reflector antenna employs a plurality of annular rings surrounding a central reflective dish and having respectively different controlled reflectivity profiles. The reflectivity-tailored reflector rings alter illumination taper and reduce selected sidelobe energy, and minimize degradation in coverage performance and gain slope in the radiation profile of the antenna. A respective ring employs a frequency selective surface laminate of layers containing different elements that resonate at different frequencies spectrally spaced to provide at least one composite frequency response characteristic.

Abstract: A spaceborne hybrid antenna reflector for dual frequency band illumination of common spot beam coverage regions contains an interior solid reflector region, that is adjacent at its perimeter to a ring-shaped exterior dichroic reflector region and adjoined by a common backing structure. The solid interior region is reflective to RF energy at each of first and second spaced apart frequency bands, while the exterior dichroic reflector region is reflective at the first frequency band, but non-reflective at the second frequency band. This allows the hybrid reflector to realize the same beamwidth coverage for a transmitter operating at one frequency band and a receiver operating at the other frequency band. The backing support frame at the rear side of the reflector is electrically decoupled from the exterior dichroic ring.

Abstract: A composite antenna reflector architecture for improving beam-to-beam isolation in a multi-spot illuminated reflector antenna employs a plurality of annular rings surrounding a central reflective dish and having respectively different controlled reflectivity profiles. The reflectivity-tailored reflector rings alter illumination taper and reduce selected sidelobe energy, and minimize degradation in coverage performance and gain slope in the radiation profile of the antenna. A respective ring employs a frequency selective surface laminate of layers containing different elements that resonate at different frequencies spectrally spaced to provide at least one composite frequency response characteristic.

Abstract: A spaceborne hybrid antenna reflector for dual frequency band illumination of common spot beam coverage regions contains an interior solid reflector region, that is adjacent at its perimeter to a ring-shaped exterior dichroic reflector region and adjoined by a common backing structure. The solid interior region is reflective to RF energy at each of first and second spaced apart frequency bands, while the exterior dichroic reflector region is reflective at the first frequency band, but non-reflective at the second frequency band. This allows the hybrid reflector to realize the same beamwidth coverage for a transmitter operating at one frequency band and a receiver operating at the other frequency band. The backing support frame at the rear side of the reflector is electrically decoupled from the exterior dichroic ring.

Abstract: An adjustable RF microwave tuning post for use in an RF cavity is disclosed. It is comprised of a flexible integrally-formed hollow tuning post disposed in the RF cavity. A drive shaft extending internally of the tuning post is provided to vary the dimensions of the tuning post. The drive shaft is connected to the tuning post at the top end thereof and connected at the other end of the drive shaft to an adjusting nut. The tuning post is made flexible by the use of bellows, which in a preferred embodiment of the invention is located along the side walls thereof.

Abstract: A phase slope equalizer is a recent device used to replace phase shifters in feed networks for satellite communications antennas. The phase slope equalizer has been further refined so that, once manufactured, it does not require tuning and is well suited to integration in larger systems. Three main embodiments are disclosed, one based on a waveguide configuration and the other two on a square coaxial configuration. In the case of the waveguide configuration half wavelength short-circuited stubs spaced by a quarter wavelength are used and in the case of one of the square coaxial configurations half wavelength open-circuited stubs spaced by a quarter wavelength are used. The third embodiment uses quarter wavelength short-circuited stubs spaced by a quarter wavelength.