Abstract: A mobile satellite radio equipped with a phased array antenna configures the phased array antenna in one or more non-directional operating modes in order to initially detect a signal from a communication satellite. Once a signal has been received from the satellite, frequency information determined in the course of operating in the one or more non-directional modes is used to configure the mobile satellite radio for operation in a subsequent stage when the phased array antenna is configured in a directional mode. In the subsequent stage the phased array antenna is used to scan a solid angle space to determine the direction of the satellite. Thereafter the antenna is used in the directional mode for satellite communication.

Abstract: Wide band Multiple-Input Multiple-Output (MIMO) antenna arrays include elements that taper from small ends located proximate to ground planes to larger ends which may be extended with vertical walls. Different shapes of tapered elements which exhibit different directivity patterns may be used in the same array and/or elements may be oriented differently such that their directivity patters peak in different directions. Each element is provided with symmetrically or asymmetrically located ground shunted conductors which serve to increase non-uniformity in the azimuthal directivity patterns. The ground shunt conductors are strategically placed to reduce element intercoupling which foster improved MIMO system performance.

Abstract: A multi-band antenna has a plurality of primary filar antenna elements and a plurality of parasitic filar antenna elements. Primary feed ends are coupled to feed signals. Parasitic feed ends are coupled to a common ground. Respective primary filar antenna elements and parasitic filar antenna elements are adjacently spaced from one another by a parasitic distance sufficiently narrow to shorten the primary and parasitic physical lengths relative to the primary and parasitic electrical lengths. The primary and parasitic filar antenna elements are capacitively coupled across the parasitic distance and can have different physical lengths. An optional additional filar antenna element has a bottom end coupled to the common ground. The additional filar antenna element can be distanced from the primary filar antenna element a separation distance sufficient to avoid capacitive coupling therebetween and can be greater than the parasitic distance. A process can obtain the parasitic distance for the antenna.

Abstract: Systems for maintain pointing of a phased array antenna in a direction maximizes to an extent possible the effective antenna gain is provided. The system includes a gyroscope and a Kalman Filter. The Kalman filter estimates an antenna pointing direction for each successive time step based on gyroscope readings and based on the results of a local search for maximum gain performed in the neighborhood of a previous antenna pointing direction.

Abstract: A system includes a phased array antenna that is used to emulate antennas that have larger solid angle coverage and lower gain compared to a single beam of the phased array antenna. This is achieved by switching between beams of the phased array antenna while receiving a wireless communication signal and summing representations of signal energy received using the different beams. The system can be used to narrow down the angular coordinates of a transmitting satellite by emulating antenna patterns that cover portions of a search space. The system can also be used to determine a channel discriminator (e.g., frequency, code, time slot) that defines a signal being transmitted.

Abstract: Multi-band quadrifilar antennas that are suitable for satellite communication include composite elements each of which include multiple conductors operating at different frequencies connected to a bus bar. Each composite element is coupled to a signal feed and to a ground structure.

Abstract: A phased array antenna for an earth terminal for a low earth orbit satellite communication system. The phased array antenna includes a set of Quadrafilar Helical Antenna's (QHAs) elements that produce a peak directivity far off-axis which partially compensates for the angular dependence of satellite systems gain which peaks at relatively lower angle. To attain the desired angular dependence of the gain and operability at high zenith angles, the QHAs are preferably spaced apart by a distance between 0.4? and 0.45?, includes filaments that have a helical pitch angle ? of between 62° and 84°.

Abstract: A multi-mode, multi-band antenna system for a handheld wireless device includes a Quadrafilar Helix Antenna (QHA) that radiates circularly polarized waves is fed by a co-axial cable. The co-axial cable is also used in combination with the QHA as a monopole antenna. Because of the distinct electromagnetic field patterns of the QHA versus the combination of the QHA and the co-axial cable operating as a monopole antenna, the cross coupling between the two modes is low. In certain embodiments the co-axial cable can itself be formed into a helix in order to reduce the physical length of the antenna system while maintaining an electrical length desired to supported certain frequency bands in the monopole mode. According to certain embodiments a post which also serves to increase the effective electric length of the co-axial cable and thereby support a lower frequency band is provided along the centerline of the QHA.

Abstract: Systems for maintain pointing of a phased array antenna in a direction maximizes to an extent possible the effective antenna gain is provided. The system includes a gyroscope and a Kalman Filter. The Kalman filter estimates an antenna pointing direction for each successive time step based on gyroscope readings and based on the results of a local search for maximum gain performed in the neighborhood of a previous antenna pointing direction.

Abstract: Multi-band quadrifilar antennas that are suitable for satellite communication include composite elements each of which include multiple conductors operating at different frequencies connected to a bus bar. Each composite element is coupled to a signal feed and to a ground structure.

Abstract: A mobile satellite radio equipped with a phased array antenna configures the phased array antenna in one or more non-directional operating modes in order to initially detect a signal from a communication satellite. Once a signal has been received from the satellite, frequency information determined in the course of operating in the one or more non-directional modes is used to configure the mobile satellite radio for operation in a subsequent stage when the phased array antenna is configured in a directional mode. In the subsequent stage the phased array antenna is used to scan a solid angle space to determine the direction of the satellite. Thereafter the antenna is used in the directional mode for satellite communication.

Abstract: A low height, space efficient, dual band monopole antenna is provided. The antenna includes a first conductive post, a second conductive post and a third conductive post extending between a lower oblong shaped PCB and an upper oblong shaped PCB. A signal is applied to a bottom end of a first conductive post and bottom ends of the remaining two posts are coupled to ground. The top of the first post is connected to the tops of the second and third posts by a serpentine trace which in one embodiment is symmetric and in another embodiment is asymmetric. The asymmetric embodiment achieves improved dual band operation without the need for an impedance matching network.

Abstract: A low height, space efficient, dual band monopole antenna is provided. The antenna includes a first conductive post, a second conductive post and a third conductive post extending between a lower oblong shaped PCB and an upper oblong shaped PCB. A signal is applied to a bottom end of a first conductive post and bottom ends of the remaining two posts are coupled to ground. The top of the first post is connected to the tops of the second and third posts by a serpentine trace which in one embodiment is symmetric and in another embodiment is asymmetric. The asymmetric embodiment achieves improved dual band operation without the need for an impedance matching network.

Abstract: A system includes a phased array antenna that is used to emulate antennas that have larger solid angle coverage and lower gain compared to a single beam of the phased array antenna. This is achieved by switching between beams of the phased array antenna while receiving a wireless communication signal and summing representations of signal energy received using the different beams. The system can be used to narrow down the angular coordinates of a transmitting satellite by emulating antenna patterns that cover portions of a search space. The system can also be used to determine a channel discriminator (e.g., frequency, code, time slot) that defines a signal being transmitted.

Abstract: A tightly integrated combined transmit and receive dual quadrifilar antenna is provided. The antenna comprises four helical transmit elements and four helical receive elements disposed about a common axis. A receiver front end includes an arrangement of two 90 degree hybrids which serve to effectively reject signals cross coupled from the transmit elements back into the receive elements, while still allowing the receiver to receive signals.

Abstract: An antenna systems for a handheld wireless device comprises an antenna disposed proximate an oblong ground structure (e.g., oblong PCB). The antenna is suitably adapted to radiated circularly polarized waves by supporting quadrature phased first and second resonances which are associated with electrical fields oriented at right angles to each other and at an oblique angle relative to a longitudinal axis of the oblong ground structure.

Abstract: Antennas that include an inner set of four helical antenna elements and a co-axially arranged outer set of four helical antenna elements. The helical winding directions of the two sets of elements may have the same handedness or opposite handedness. Certain embodiments provide for switch handedness of circularly polarized radiation of the antennas and certain embodiments provide for shifting the directivity of the antenna pattern in polar angle. Systems in which the antennas are used and methods of use are also taught.

Abstract: An antenna systems for a handheld wireless device comprises an antenna disposed proximate an oblong ground structure (e.g., oblong PCB). The antenna is suitably adapted to radiated circularly polarized waves by supporting quadrature phased first and second resonances which are associated with electrical fields oriented at right angles to each other and at an oblique angle relative to a longitudinal axis of the oblong ground structure.

Abstract: Antennas that include an inner set of four helical antenna elements and a co-axially arranged outer set of four helical antenna elements. The helical winding directions of the two sets of elements may have the same handedness or opposite handedness. Certain embodiments provide for switch handedness of circularly polarized radiation of the antennas and certain embodiments provide for shifting the directivity of the antenna pattern in polar angle. Systems in which the antennas are used and methods of use are also taught.

Abstract: Multi-band quadrifilar antennas that are suitable for satellite communication include composite elements each of which include multiple conductors operating at different frequencies connected to a bus bar. Each composite element is coupled to a signal feed and to a ground structure.