Abstract: A dual-frequency conformal multi-filiar helical antenna system (20) provides a low-profile, low drag antenna useable in flying equipment. This antenna system (20) securely holds within its shell (22) signal distribution circuitry (64), signal combining circuitry (68), and any other circuit components necessary for antenna system (20) to communicate with other stations or devices. Antenna system (20) has radiating conductors (24, 32) tuned to two different frequencies such that simultaneous transmission and reception of signals is possible in the same and opposite directions.

Abstract: A dual-frequency conformal multi-filiar helical antenna system (20) provides a low-profile, low drag antenna useable in flying equipment. This antenna system (20) securely holds within its shell (22) signal distribution circuitry (64), signal combining circuitry (68), and any other circuit components necessary for antenna system (20) to communicate with other stations or devices. Antenna system (20) has radiating conductors (24, 32) tuned to two different frequencies such that simultaneous transmission and reception of signals is possible in the same and opposite directions.

Abstract: A planar array antenna for use with an earth-based subscriber unit generates receive or transmit communications beams through the use of digital beamforming networks (210, 211) which provide beam steering in a first dimension. In another dimension, the communications beams are synthesized by way of a waveguide structure (300, FIG. 3) which is repeated for each row of the antenna array. The waveguide outputs are weighted due to the positioning of coupling slots (350) or coupling probes (450) which transfer carrier signals to and from each waveguide. The slots or coupling probes from the waveguides are coupled to a group of barium strontium titanate (BST) (360, FIG. 3) or micro-electromechanical systems (MEMS) switch (460, FIG. 4) phase shift elements which are under the control of a control network (221, 222, FIG. 2). The resulting signals are radiated by the antenna elements of the planar antenna array (310, FIG. 3) to form a communications beam.

Abstract: A dual pattern antenna (FIG. 1, 20) functions as a bi-filar or quadrifilar helical antenna depending of the location of the feed element (FIG. 4, 120). When the feed element (120), within the hollow dielectric tube (FIG. 4, 140), is used to feed the antenna (20) at a distal end portion (FIG. 4, 142) the antenna functions as a bi-filar helical antenna and exhibits a relatively omnidirectional radiation pattern (FIG. 3, 70). When the feed element is used to feed the antenna at a proximal end portion (FIG. 4, 141), the antenna (20) functions as a quadrifilar helical antenna having a radiation pattern which exhibits desirable gain properties in the area above the antenna (FIG. 4, 40). The use of capacitive coupling allows the feed element (120) to slide within the hollow dielectric tube (140) so that the pattern of the antenna can be quickly changed, thus making the antenna well-suited for portable communications devices such as satellite cellular telephones.

Abstract: A scanning array antenna (300) produces a directional beam by differentially rotating two, co-axial, flat phasing plate assemblies (302, 304). Each plate (302, 304) consists of a phase shifting means designed to efficiently pass incident radio frequency (RF) energy while imparting a particular phase shift to the energy. The energy can be supplied by a feedhorn (406) located behind the plates (402, 404) or can be introduced above the plates (508) and reflected by a ground plane (506) on the bottom plate (504). A method for producing the directional beam using the scanning array antenna (300) determines (804) the desired beam direction, calculates (806) the appropriate plate rotation angles (326, 328), and rotates (808) the plates (302, 304) at the appropriate time.