Abstract: A modular direct radiating antenna system for producing highly contoured beam patterns is disclosed. The system comprises a plurality of array modules, each having a number of radiation elements. An intramodule feed network is provided to communicate RF energy between a module port and the radiation elements in an equal-power, equal-phase relationship. A second feed network, an intermodule feed network, is provided to communicate RF energy between an antenna system port and the respective module ports. The second feed network is adapted to couple the power and adjust the electrical path lengths so that the RF power communicate between the respective module ports and the system port is of predetermined relative amplitudes and phases. The intermodule excitation power and phase distribution across the entire planar array aperture produces the desired contoured beam to encompass a required area.

Abstract: A test and measurement system for space satellite antennas which includes frequency synthesizers which are capable of shifting from frequency to frequency at high speeds with precision accuracy to provide source and reference frequencies with which the antennas may be tested; a transmitter utilizing one of the frequency synthesizers to generate test signals; an optional power monitor receiving antenna; a non coherent receiver utilizing the other of the frequency synthesizers to generate local reference frequency signals; high speed electronic switching networks connecting the various antennas to be tested with the receiver at the receiving antenna; a network for converting received signals to digital signals and storing those signals; and a computer system for controlling the transmitter, the receiver, and the switching systems, and the data converting and storage network.

Abstract: There are herein described microwave devices that are mounted at the output ends of circularly polarized horn antennas of a microwave antenna array. The devices act as coupling compensators between the horns, and also function as singular or dual polarization trimmers to create very low axial ratio circularly polarized antenna array patterns through a broad angular range. In each of these devices, a parasitic element is disposed on a planar substrate that is orthogonally positioned with respect to the direction of propagation from the horn antennas.

Abstract: A horn antenna is disclosed having a built-in circular polarizer and a cross polarization attenuator. A square-apertured horn antenna has a plurality of pairs of conductive fins disposed along opposite edges of the horn interior. The individual fins are separated from each other by approximately one-fourth wavelength. The fins are at a 45 degree angle to that linear wave and react with that linear wave by imparting a circular rotation to that wave as the wave propagates past each pair of fins. A stepped attenuator is mounted in the input section to the horn antenna perpendicular to the linear input wave. The attenuator substantially absorbs cross-polarized signals whether reflected from the aperture of the horn or provided by the incoming signal.

Abstract: A multisided horn antenna such as a square horn is disclosed having an improved axial ratio circular polarization or ellipticity. Ellipticity of a square horn antenna is improved by placing a conical section or ring of conductive material at the aperture of a horn antenna. The conical ring causes a relatively directive beam having a low axial ratio to be produced throughout most of the pattern generated similar to that of a conical horn antenna. Yet, the square horn antenna provides increased power over a conical horn.