Abstract: An antenna feed network includes a septum polarizer including a waveguide defining a cavity, wherein a septum is disposed in the cavity to divide the cavity to form a first port and as second port, a diplexer in signal communication with at least one of the first port and the second port of the septum polarizer to route a signal based upon a frequency, and a wave coupler/splitter in signal communication with the diplexer to send and receive signals therebetween, the wave coupler/splitter including a first signal path and a second signal path, wherein the wave coupler/splitter controls a phase shift of a signal transmitted through at least one of the first signal path and the second signal path.

Abstract: A GPS-at-GEO system is provided that includes a receive antenna design that enables improved tracking of GPS space vehicle side-lobe signals. The receive antenna design is a conical mode helix antenna configured to produce a conical mode radiation pattern, which has zero gain at Nadir and higher gain in the side-lobe signal regions. The conical mode radiation pattern provides several advantages for GPS-at-GEO navigation applications. For example, this mode provides higher gain in the GPS space vehicle side-lobe signal regions for improved acquisition and tracking performance and lower gain at Nadir, providing reduced noise temperature and higher signal to noise ratio.

Abstract: A directive monopole antenna element with good RF performance (e.g., directivity and cross-polarization) and a low assembly cost is provided. The directive monopole antenna includes a dielectric support structure and one or more conductive directors coupled to the support structure. Each of the conductive directors is disposed parallel to every other conductive director and in a first plane of the support structure. The directive monopole antenna further includes a conductor coupled to an end of the support structure. The conductor has a feed probe section disposed in the first plane perpendicular to the one or more conductive directors and extending beyond the end of the support structure. The conductor further has a bent section disposed in the first plane parallel to the one or more conductive directors. The feed probe section and the bent section are electrically coupled. The directive monopole antenna element may be fed by a waveguide or a coaxial feed line.

Abstract: A helical antenna having a central axis defined between a base end and a distal end comprises a helical conductor wound about the central axis and having a feed line disposed at the base end and along the central axis, and may also include an elongated dielectric core about which the electrical conductor is wound.