Abstract: The present invention relates to phased array antenna arrangements which comprise a linear array of feed elements where the array has an aperture which is out at a bias angle along the minor axis of the array to produce a fixed linear phase taper along the minor axis by all elements. Then by linearly scanning the array along the major axis of the aperture of the array, a beam is scanned along an arc which can be made to correspond to an orbital arc segment around a celestial body and within the field of view of the antenna arrangement when the bias angle is properly chosen. The feed elements can comprise long feedhorns or horn antenna configurations which can be used in a separate array or disposed in an array on a conjugate plane of a main cylindrical reflector when used in multiple reflector phased array antenna arrangements.

Abstract: The present invention relates to an array phasing technique which normally provides directional spotbeams, and in the event of a failure mode of a phase shift controller for providing a wide area coverage beam. In an arrangement for practicing the present technique, each array feed element has disposed at its input a serial arrangement of a fixed value phase shifter (32) and a variable phase shifter (34). Each variable phase shifter has a separate control signal supplied to it by a phase shift controller (36). During normal operation the combined fixed value and variable phase shifters cause the array to radiate a flat wavefront in a predetermined direction, and in a failure mode of the phase shift controller the fixed phase shifters cause the array to radiate a diverging area coverage beam.

Abstract: The present invention relates to a phased array antenna system which, in the transmission mode, forms a directional planar wavefront (20) including a signal at a first frequency at a first array (18.sub.1 -18.sub.m) which is a sub-multiple of the frequency to be ultimately transmitted. By sending the wavefront through a lens or reflector, an image of the first array is formed on an image plane. A second array (26.sub.1 -26.sub.n) disposed at the image plane intercepts the wavefront and the received signal's frequency and phase is then harmonically multiplied by a predetermined number to permit reradiation of the resultant signal by a third array (32.sub.1 -32.sub.n) in the same direction as the original wavefront. The second and third arrays include corresponding elements and configurations with more elements than the first array. In the receive mode, the sequence is complementary to the transmit mode.

Abstract: The present invention relates to a quasi-optical frequency diplexer capable of operating over a wide angle of scan and separating microwave signals possessing proximate center frequencies. The present invention, which in one aspect may be employed with a phased array antenna arrangement functioning so as to separate the transmit and receive frequencies associated therewith, consists of an array of waveguide sections (22) where the input and output ports (30, 32) of the array are tilted with respect to the array's longitudinal axis. The angles of tilt and the dimensions of the waveguide sections may be adjusted so as to achieve frequency diplexing with a minimal amount of interference between the diplexed signals.

Abstract: The present invention relates to a method for reducing the grating lobes associated with phased array antenna arrangements. The present invention, which may be employed with any phased array antenna arrangement, consists of disposing a filtering means capable of blocking the grating lobes at any real focal point in the focal plane of the antenna arrangement. The size of the central region of the filter is determined by the desired field of view at the far-field, and may be adjusted so as to reduce the grating lobes to an admissible level with minimal gain degradation of the main beam.

Abstract: The present invention relates to antennas which have reflector arrangements that produce a large image with minimal aberrations at the exit aperture thereof of a small feed array. In the present arrangement, the feed array is placed at the conjugate plane relative to the exit aperture of a geometrically confocal reflector system comprising a parabolic main reflector and a parabolic subreflector so that exact imaging of the array is obtained at the exit aperture. In such arrangements, alignment and surface accuracy errors of the various reflectors can be easily corrected by appropriately changing the phase or the position of the associated elements of the feed array. A three-reflector arrangement having sequential geometric confocality is disclosed which also alters the focal length of the main reflector sufficiently to permit the inclusion of polarization and/or frequency diplexing means in the overall reflector system.

Abstract: The present invention relates to novel launcher reflectors which are used with reflector antenna systems to compensate for the dominant aberration of astigmatism which was found to be introduced in the signals being radiated and/or received at the off-axis positions. A major portion of such phase error is corrected by using, with each off-axis feedhorn, an astigmatic launcher reflector having a curvature and orientation of its two orthogonal principal planes of curvature which are chosen in accordance with specific relationships, the launcher reflector being fed by a symmetrical feedhorn.