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 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 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: 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: 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: A quadrifilar antenna having helical windings is fed by a phase shift feed network, each winding having an open circuit termination element, the phase shift feeding network having forward directional phase shift paths from a feed input to phase shift feed output ports, and having a first reverse directional transmission path from one or more of the phase shift feed output ports back to a first isolation port, and a second reverse directional transmission path from another one or more of the phase shift feed output ports back to a second isolation port, the first and second isolation ports isolated from the forward directional phase shift paths, and a differential termination impedance, floating from ground, connected the first and second isolation ports. Optionally, the differential termination impedance is frequency selective.

Abstract: An antenna includes a body having first and second lateral arms. The body also includes a central offset section connecting to the first and the second lateral arms, and first and second antenna ports connected to the central offset section. The antenna has a bandwidth greater than a maximum frequency shift of a resonance frequency of the antenna caused by a loading of the antenna by a human hand.

Abstract: A network system and a method of determining a location of a transmitter are described. The method includes reading a signal strength of a signal transmitted by the transmitter by each of a plurality of receivers, at each frequency in a plurality of frequencies, extracting phase information using an amplitude of the signal at each of the plurality of frequencies, and applying a transform (such as a Fourier Transform) to the signal in the frequency domain to obtain a representation of the signal in the time-domain. The method further includes applying a time window to the signal in the time-domain to eliminate reflected multipath signals that arrive to the respective receivers later than a line-of-sight signal to obtain a windowed signal in the time domain, and calculating a location of the transceiver using the windowed time domain signal.

Abstract: A quadrifilar antenna having helical windings is fed by a phase shift feed network, each winding having an open circuit termination element, the phase shift feeding network having forward directional phase shift paths from a feed input to phase shift feed output ports, and having a first reverse directional transmission path from one or more of the phase shift feed output ports back to a first isolation port, and a second reverse directional transmission path from another one or more of the phase shift feed output ports back to a second isolation port, the first and second isolation ports isolated from the forward directional phase shift paths, and a differential termination impedance, floating from ground, connected the first and second isolation ports. Optionally, the differential termination impedance is frequency selective.

Abstract: A Proximity Coupled-Folded-J Antenna PC-FJA (104) includes a ground plane (240), first resonant element (352) with a “J” shape that resonates at a first radio frequency, a second resonant element (350) positioned within the “J” shape and that resonates at a second radio frequency, and a third resonant element (118) with a portion that is substantially parallel to and removed from the plane of the “J” shape and that resonates at a third radio frequency. The PC-FJA (104) has a fourth resonant element (130) with a loop (132) in a plane perpendicular to and removed from the plane of the “J” shape. The fourth resonant element (130) resonates at a fourth radio frequency. These elements are ohmically coupled to a connection arm (108). The ground plane (240) is removed from PC-FJA (104) and is perpendicular to the plane of the “J” shape.

Abstract: A Proximity Coupled-Folded-J Antenna PC-FJA (104) includes a ground plane (240), first resonant element (352) with a “J” shape that resonates at a first radio frequency, a second resonant element (350) positioned within the “J” shape and that resonates at a second radio frequency, and a third resonant element (118) with a portion that is substantially parallel to and removed from the plane of the “J” shape and that resonates at a third radio frequency. The PC-FJA (104) has a fourth resonant element (130) with a loop (132) in a plane perpendicular to and removed from the plane of the “J” shape. The fourth resonant element (130) resonates at a fourth radio frequency. These elements are ohmically coupled to a connection arm (108). The ground plane (240) is removed from PC-FJA (104) and is perpendicular to the plane of the “J” shape.

Abstract: A folded helical antenna. Generally, the inventive antenna includes plural radiating elements of conductive material. In the preferred embodiment, the antenna is a quadrifilar helix antenna having four radiating elements. Each radiating element is constrained into a helical shape. In accordance with the present teachings, each radiating element extends in a first direction and has a portion thereof folded in a second direction, the second direction being substantially parallel to the first direction. The novel method of making a quadrifilar helix antenna of the invention includes the steps of: ascertaining desired antenna characteristics for a given application; ascertaining limitations on antenna height for the application; fabricating a helical antenna in accordance with the desired antenna characteristics; and adjusting the height of the antenna in accordance with the limitations by folding the radiating elements thereof.