Abstract: A beam forming network system includes a first beam forming network having first and second ports, in which each of the first ports is operatively coupled to an antenna element; and a second beam forming network including third and fourth ports, in which each of the third ports is operatively coupled to one of the second ports using at least one of a phase shifter, attenuator, power divider, and/or hybrid coupler. A method of beam forming includes coupling each of the first ports associated with a first beam forming network operatively to one antenna element, and coupling each of the third ports associated with a second beam forming network operatively to one of the second ports associated with the first beam forming network using at least one of a phase shifter, attenuator, power divider, and/or hybrid coupler.

Abstract: Methods and apparatus for providing a generic beamforming system. A first beamforming level can process digitized array data to form subarrays and output subarray data for the formed subarrays. A second beamforming level can process the subarray data to form beams and output beamforming data for a plurality of modules. A third beamforming level can process the beamforming data to process the beamforming data and generate formed beams for the array.

Abstract: A system and method for providing confidentiality against eavesdropping and authentication against impersonation attacks for advanced wireless communication systems are disclosed. The method exploits ARQ as a MAC layer mechanism and artificial noise as a physical layer mechanism with maximal ratio combining to achieve secrecy. An artificial noise, not requiring class space in the channel, is designed and added to the data package based on the QoS requirements and channel condition between legitimate parties. Basically, a special AN, which does not require null-space in the channel, is designed based on the QoS requirements and the channel condition between the legitimate parties and injected to the data packet. If the same packet is requested by the legitimate receiver (Bob), an AN cancelling signal is designed and added to the next packet. Then, an AN-free packet is obtained by using MRC process at Bob, while deteriorating the eavesdropper's performance.

Abstract: A transponder system is presented, comprising first and second antenna arrays each comprising a plurality of antenna elements arranged in a predetermined geometry. The antenna elements of the first antenna array are respectively interconnected with corresponding antenna elements of the second antenna array by respective connection lines thereby forming plurality of receiving-transmitting pairs of antenna elements. A receiving-transmitting pair is configured to receive an input electro-magnetic signal by one antenna element thereof and transmit a corresponding output signal by the other antenna element, thereby enabling collective collection of a signal waveform and transmission of a corresponding output signal waveform. The first and second antenna arrays are rotatable with respect to one another about at least one predetermined rotation axis, thereby enabling variation of direction of propagation of the output signal waveform with respect to direction of propagation of the collected signal waveform.

Abstract: An antenna array system provides simultaneous 360° coverage and includes Butler matrix beam forming networks connected to an antenna array, which includes narrow and/or broadband elements, and multiple transmitters, receivers, or transceivers to allow for 360° transmission and/or reception. The antenna array system can provide multiple beams, such as without limitation 8 or 16 beams, which can vary in beam crossing and/or overlap to provide simultaneous 360° coverage. An antenna array system includes a plurality of antenna elements configured in an array, a first Butler matrix operatively coupled to the plurality of antenna elements, and a second Butler matrix operatively coupled to the first Butler matrix. A method of providing simultaneous 360° coverage includes configuring a plurality of antenna elements in an array, coupling a first Butler matrix operatively to the plurality of antenna elements, and coupling a second Butler matrix operatively to the first Butler matrix.

Abstract: According to various embodiments disclosed herein, an electronic device includes a transceiver configured to generate a first signal and a second signal, a first coupler configured to receive the first signal from the transceiver and provide the first signal to the first antenna; a second coupler configured to receive the second signal from the transceiver and provide the second signal to the second antenna; and a control circuitry operatively connected to the transceiver. The control circuitry is configured to determine values associated with a phase difference between the first signal and the second signal at least partially based on the signals from the first coupler and the second coupler, and to cause the transceiver to adjust a phase of the first signal and/or a phase of the second signal using at least some of the values in order to reduce or remove the phase difference. Other embodiments have been provided.

Abstract: Systems and methods for supporting more flexible coverage areas and spatial capacity assignments using satellite communications systems are disclosed. A hub-spoke, bent-pipe satellite communications system includes: terminals; gateways; a controller for specifying data for controlling satellite operations in accordance with a frame definition including timeslots for a frame and defining an allocation of capacity between forward and return traffic. The satellite communications system may employ a satellite with a feed array assembly and may use on-board beamforming or ground-based beamforming. Beam hopping within timeslots of the frame may be used to provide coverage to different cells in different time periods. The flexible coverage areas may be provided using changes in satellite position, antenna patterns, or beam resource allocations.

Abstract: A radar system includes a plurality of radiating elements configured to radiate electromagnetic energy and a plurality of feed waveguides defining a common plane and configured to guide electromagnetic energy to the plurality of radiating elements. The radar system also includes a plurality of waveguides arranged as a dividing network, where the dividing network includes one or more coupling apertures located in the common plane. The dividing network is configured to receive electromagnetic energy from a source and split the electromagnetic energy among the plurality of feed waveguides, such that each feed waveguide receives a respective portion of the electromagnetic energy. The splitting and adjusting of the radar system are based in part on the one or more coupling apertures in the dividing network.

Abstract: Techniques for static tuning retro-directive wireless power transmission systems are described herein. The techniques described herein include systems, methods and software for establishing a static tuning mode for a retro-directive wireless power transmission system. The static tuning mode can generate an extended stable power sphere that facilitates accurate RF and other measurements. Additionally, techniques are provided for characterizing the wireless power delivery paths.

Abstract: A passive frequency multiplexer includes a beam forming network lens including a plurality of input terminals and a plurality of output terminals; a transmission line for transmitting a signal to the beam forming lens; and a plurality of couplers arranged in series along the transmission line, each of the plurality of couplers comprising an input terminal, an output terminal, and a coupled output terminal, each of the coupled output terminals of the plurality of couplers being coupled to a respective one of the input terminals of the beam forming network lens.

Abstract: There are provided an antenna apparatus and a method of handover using the antenna apparatus. The antenna apparatus may comprise a plurality of antenna elements forming a plurality of beams in a predetermined service area. The plurality of antenna elements are arranged in a plurality of rows, and a number of antenna elements included in an uppermost row of the plurality of rows is smaller than a number of antenna elements included in a downmost row of the plurality of rows, and differences between center angles of beams formed by the antenna elements included in the downmost row are larger than differences between center angles of beams formed by the antenna elements included in the uppermost row.

Abstract: Aspects of the subject disclosure may include, for example, antenna that includes a first plurality of antenna elements radially arranged in a first plane to wirelessly transmit first channel signals received from a guided wave communication system to a plurality of client devices via a first plurality of beams at a corresponding first plurality of angles. A second plurality of antenna elements are radially arranged in a second plane that is displaced a first distance from the first plane to wirelessly transmit second channel signals received from the guided wave communication system to the plurality of client devices via a second plurality of beams at a corresponding second plurality of angles that are angularly displaced from the first plurality of angles. Other embodiments are disclosed.

Abstract: In systems and methods for establishing communication between a wireless device and a communication network, one or more sounding signals are received from one or more relay nodes. One or more parameters of beam formation are determined based on the received one or more sounding signals. Formation of one or more beams is initiated from two or more antennas to the one or more relay nodes based on the determined one or more beam formation parameters. The total number of the formed beams and the formation of the beams are adjusted dynamically based on the received sounding signals from the relay nodes.

Abstract: The present invention relates to an antenna able to cover two opposite angular sectors comprising: first and second excited elements (10,11) each able to radiate a signal beam at a predetermined frequency, at least two reflector elements (20,21,22,23), called first and second reflector elements, able to reflect said beams in opposite directions. According to the invention, said first and second excited elements (10,11) and said at least two reflector elements (20,21,22,23) are aligned, said reflector elements being disposed between said first and second excited elements. At least two reflector elements from among said at least two reflector elements (20,21,22,23) are connected together electrically by a first transmission line (30) of predetermined length so that the reflector elements connected together participate jointly in reflecting the beams in the two opposite directions.

Abstract: A signal generator generates an electrical signal that is sent to an amplifier, which increases the power of the signal using power from a power source. The amplified signal is fed to a sender transducer to generate ultrasonic waves that can be focused and sent to a receiver. The receiver transducer converts the ultrasonic waves back into electrical energy and stores it in an energy storage device, such as a battery, or uses the electrical energy to power a device. In this way, a device can be remotely charged or powered without having to be tethered to an electrical outlet.

Abstract: A signal generator generates an electrical signal that is sent to an amplifier, which increases the power of the signal using power from a power source. The amplified signal is fed to a sender transducer to generate ultrasonic waves that can be focused and sent to a receiver. The receiver transducer converts the ultrasonic waves back into electrical energy and stores it in an energy storage device, such as a battery, or uses the electrical energy to power a device. In this way, a device can be remotely charged or powered without having to be tethered to an electrical outlet.

Abstract: A beam-forming network for an emitting array antenna having at least NB input ports connected to respective beam ports of the beam-forming network and at least NOSA>1 output ports, for associating to each output port a linear combination of input signals from respective input ports; a set of at least NOSA lossless single-mode networks, each having an input port connected to a respective output port of multi-beam network and at least NNOSAOSA>1 output ports, for associating to each output port a signal obtained by weighting an input signal from the input port; and a set of at least NNOSA?NNOSAOSA lossless multi-mode networks, each having at least NNOSAOSA NOSANOSA input ports, each one connected to an output port of a respective single-mode network, and at least NENOSA>1 output ports connected to respective antenna ports of the beam-forming network, for associating to each output port a linear combination of input signals from respective input ports.

Abstract: The disclosed embodiments relate to a technique for calibrating a retro-directive array. During the calibration process, the system measures a gain g1 through a first pair of antennas in the retro-directive array. Next, the system measures a gain g2 through a second pair of antennas in the retro-directive array. The system then simultaneously measures a combined gain G1,2 through the first and second pairs of antennas in the retro-directive array. If G1,2 is less than g1+g2 by more than a threshold value, the system calibrates a phase relationship between the first and second pairs of antennas.

Abstract: In some embodiments a beamforming method is disclosed. The method can include transmitting a beam having a channel defined by a maximum ratio transmission vector (MRT) and receiving a first response from a receiver, where the first response has first information such as parameters related to the transmitted beam. Using the parameters and the initial MRT, another directional transmission can be made. A similar process can determine a maximum combining ratio for a receiver. Set up communications between the transmitter and the receiver can be reduced by omitting data from transmission that can be acquired by other means such as from memory or calculations. Additional embodiments are also disclosed.

Abstract: A transponder system including first and second arrays of receiving and transmitting antenna elements arranged in spaced apart relationship with a predetermined spacing. The antenna elements of the first array are connected, via respective transmission modules, to respective antenna elements of the second array in accordance with their positions in the arrays thus forming receiving and transmitting pairs of antenna elements. The transmission modules include: a sampler adapted for digitizing signals received by the receiving antenna element of the corresponding pair, a memory for storing a digital representation of the received signals, and a signal generation module operable for generating from the digital representation a signal to be transmitted by the transmitting antenna element of the corresponding pair with a predetermined temporal delay to thereby provide a predetermined angular shift between a waveform of the received input signal and a waveform of the collective output signal.

Abstract: A method includes pointing a receive beam of a retro-directive antenna array attracted to a jammer circuit instead of a remote transmitter away from the jammer circuit toward the remote transmitter by a first angle based on coarse manual means therefor implemented in electronic circuitry associated with the retro-directive antenna array. The electronic circuitry includes a number of mixers, each of which is configured to mix a Local Oscillator (LO) signal generated from a Voltage Controlled Oscillator (VCO) with a signal received at an antenna element of the retro-directive antenna array. The method also includes automatically fine pointing the receive beam toward the remote transmitter by a second angle following the coarse pointing thereof by the first angle such that the receive beam exactly points to, and tracks, the remote transmitter. The automatic fine pointing is effected through a secondary automatic servo loop implemented in the electronic circuitry.

Abstract: A passive wireless tag assembly comprises a plurality of antennas and transmission lines interconnected with circuitry and constructed and arranged in a Van Atta array or configuration to reflect an interrogator signal in the direction from where it came. The circuitry may comprise at least one surface acoustic wave (SAW)-based circuit that functions as a signal reflector and is operatively connected with an information circuit. In another embodiment, at least one delay circuit and/or at least one passive modulation circuit(s) are utilized. In yet another embodiment, antennas connected to SAW-based devices are mounted to at least one of the orthogonal surfaces of a corner reflector.

Abstract: An active retrodirective antenna array is provisioned with a virtual beacon for use with uncooperative targets. An RF pilot signal is imposed onto an optical carrier beam and directed at a target. The scattered optical carrier beam is optically detected by a plurality of the retrodirective array nodes to extract the RF pilot signal. Each recovered RF pilot-signal is phase-conjugated with a phase reference signal, amplified and retransmitted towards the target where the RF beams add-in phase at the virtual beacon. The array may be used to complete an RF communication link with the target, to transfer microwave power from orbiting solar power stations to a target or as a directed energy weapon to prosecute the target.

Abstract: Embodiments of the invention are directed to retrodirective radio-frequency systems wherein a transmit antenna array includes at least one row of N transmit elements and a receive antenna array includes at least one row of N receive elements that correspond one-to-one to the transmit elements and wherein the transmit and receive elements are located on spaced planes, and centered about a common axis and located at common transmit distance and a common receive distance, respectively. In some embodiments the one row of transmit and receive elements comprises “n” rows of elements, where “n” is an integer greater than one, thereby forming a two-dimensional array. In some embodiments the total transmit radiation pattern provides an azimuth coverage of 360 degrees. In other embodiments, it may provide less coverage but be operable as independent sectors.

Abstract: A beamforming radio frequency (RF) circuit includes a plurality of antennas, a plurality of amplifiers and an adjust module. The plurality of antennas is operably coupled to interrelate a plurality of beamformed signal components with a beamformed signal. The plurality of amplifiers is operably coupled to interrelate the plurality of beamformed signal components with a plurality of adjusted signal components. The adjust module is operably coupled to interrelate coordinates of a signal with the plurality of adjusted signal components.

Abstract: A retrodirective antenna system (1) for receiving an incoming signal (15) from an object (13) and directing an outgoing signal (11) back to the object (13), comprising two or more transceiver cells (3), each of which receives a part of the incoming signal, produces a phase conjugate output signal, which output signals from the cells combine to form an outgoing signal (11) directed back to the object (13), wherein each transceiver cell (3) comprises an antenna component (7) which detects the part of the incoming signal, a processor which receives the part of the incoming signal and produces first and second same-side, sideband (SB) signals of the part of the incoming signal, a phase shift system comprising a first phase element which receives the first SB signal and outputs a SB signal having a first phase, and a second phase element which receives the second SB signal and outputs a SB signal having a second phase which is in quadrature with the first phase, and an IQ modulator comprising an I input port, a Q

Abstract: Techniques are provided for wireless communication between a first wireless communication device and a second wireless communication device. At a plurality of antennas of the first wireless communication device, one or more signals transmitted by a second wireless communication device in a first frequency band are received. Beamforming weights are computed from information derived from the signals received at the plurality of antennas using one or more of a plurality of methods without feedback information from the second wireless communication device about a wireless link from the first wireless communication device to the second wireless communication device. The beamforming weights are applied to at least one transmit signal to beamform the at least one transmit signal for transmission to the second wireless communication device in a second frequency band.

Abstract: A beamforming radio frequency (RF) circuit includes a plurality of antennas, a plurality of amplifiers and an adjust module. The plurality of antennas is operably coupled to interrelate a plurality of beamformed signal components with a beamformed signal. The plurality of amplifiers is operably coupled to interrelate the plurality of beamformed signal components with a plurality of adjusted signal components. The adjust module is operably coupled to interrelate coordinates of a signal with the plurality of adjusted signal components.

Abstract: The Method for transmitting a signal from a transmitter in an area around the transmitter via a satellite comprising the steps of transmitting a first signal having a first frequency from the transmitter to a satellite having a retrodirective antenna array comprising receiving antennas and transmitting antennas, receiving the signal transmitted from the transmitter by the receiving antennas of the retrodirective antenna array as first signals wherein the first signals received by the receiving antennas have a phase relation among each other defined by the geometric arrangement of the receiving antennas, and retrodirectively re-transmitting second signals from the transmitting antennas of the antenna array of the satellite in the direction towards the transmitter in the form of a beam with the transmitter located substantially in the center of the beam wherein the second signal has a second frequency different from the first frequency and wherein the phase relations among the second signal transmitted from

Abstract: A retrodirective antenna system (1) for receiving an incoming signal (15) from an object (13) and directing an outgoing signal (11) back to the object (13), comprising two or more transceiver cells (3), each of which receives a part of the incoming signal, produces a phase conjugate output signal, which output signals from the cells combine to form an outgoing signal (11) directed back to the object (13), wherein each transceiver cell (3) comprises an antenna component (7) which detects the part of the incoming signal, a processor which receives the part of the incoming signal and produces first and second same-side, sideband (SB) signals of the part of the incoming signal, a phase shift system comprising a first phase element which receives the first SB signal and outputs a SB signal having a first phase, and a second phase element which receives the second SB signal and outputs a SB signal having a second phase which is in quadrature with the first phase, and an IQ modulator comprising an I input port, a Q

Abstract: A wireless power transmission system including at least one source of electromagnetic radiation, a plurality of wireless power receivers that receive radiated electromagnetic energy, a beacon collocated with each wireless power receiver, wherein the beacon generates and radiates a pilot signal when the beacon is in an active state, and an array of transmitting antennas connected to the source of electromagnetic radiation that radiates the electromagnetic radiation in the direction of the beacon in the active state. The electromagnetic radiation can be electronically steered from one wireless power receiver to another by activating and deactivating the beacons collocated with each wireless power receiver.

Abstract: Embodiments provide radio-frequency systems that can automatically detect, focus-on, and track objects in the environment without the need for expensive electronic scanning and phase-shifting components. Some embodiments are directed to retrodirective systems including: (1) quiescently broadcast pseudorandom-modulated radiation, such as pseudorandom bit sequences, in the absence of a target, over a field-of-view comparable to the beam solid angle of a single element in the transmit array; (2) a receive antenna element or array, in a desired spatial relationship with respect to the transmit antenna array, that receives reflected pseudorandom radiation from a target; and (3) an electronic signal-processing and feedback channel between the receive and transmit arrays that carries out cross-correlation between the received radiation and the transmitted pseudorandom signals and computes complex correlation coefficients to form a re-transmitted beam.

Abstract: Embodiments provide radio-frequency systems that can automatically detect, focus-on, and track objects in the environment without the need for expensive electronic scanning and phase-shifting components. Some embodiments are directed to retrodirective systems including: (1) quiescently broadcast pseudorandom-modulated radiation, such as pseudorandom bit sequences, in the absence of a target, over a field-of-view comparable to the beam solid angle of a single element in the transmit array; (2) a receive antenna element or array, in a desired spatial relationship with respect to the transmit antenna array, that receives reflected pseudorandom radiation from a target; and (3) an electronic signal-processing and feedback channel between the receive and transmit arrays that carries out cross-correlation between the received radiation and the transmitted pseudorandom signals and computes complex correlation coefficients to form a re-transmitted beam.

Abstract: A retro-directive antenna for communicating with a geostationary satellite autonomously detects the direction from which a signal is received, and transmits a beam that points back along the same direction. An array feed is used to illuminate a parabolic reflector. Each feed element of the retro-directive antenna is associated with a unique pointing direction of the beam in the far field. As the transmit energy is switched to different feed elements, the far-field beam is scanned, making it possible to track a geostationary satellite in a slightly inclined orbit. This eliminates the need for mechanical tracking and maintains high antenna gain in the direction of the geostationary satellite. The use of a toroidal reflector with multiple linear array feeds spaced in the azimuth direction enables multi-beam operation, allowing multiple geostationary satellites, spaced by up to fifteen beam widths in azimuth, to be tracked simultaneously and independently.

Abstract: A beamforming radio frequency (RF) circuit includes a plurality of antennas, a plurality of amplifiers and an adjust module. The plurality of antennas is operably coupled to interrelate a plurality of beamformed signal components with a beamformed signal. The plurality of amplifiers is operably coupled to interrelate the plurality of beamformed signal components with a plurality of adjusted signal components. The adjust module is operably coupled to interrelate coordinates of a signal with the plurality of adjusted signal components.

Abstract: A method and system for analog beamforming in wireless communication system, is provided. Analog beamforming coefficients are constructed by performing an iterative beam acquisition process based on beam search training, and determining optimized beamforming weighting coefficients based on the iterative beam acquisition process.

Abstract: A phased array satellite communication (SATCOM) system for ground stations receives information signals and a beam from a satellite and autonomously steers communication signals by phase information toward a satellite extracted from the received satellite beam. The new phased array eliminates the need for phase shifters to control a beam. The new phased array satellite communications system avoids delay in digital signal processing or feedback systems to find satellite locations, enabling autonomous real-time electronic beam steering with no delay. The new system is also used to handle signals from and to multiple satellites simultaneously. The new system is useful in other applications where an enhanced point-to-point communication link is required.

Abstract: Provided is an antenna transceiver system for transmitting and receiving voice, digital data, radar and IR signals, and for processing received signals for use by an operator. The system includes an antenna array having a plurality of radiating elements, each element connected to a transmit/receive (“T/R”) module. Each T/R module includes phase shifters, as well as a phase conjugation module for transmitting a return signal to a location along a beam path of an incoming signal. Transmission of the return signal does not require knowledge of the location of either the signal source or the antenna transceiver system. The antenna transceiver system is disposed on a plurality of vertically aligned planes integrated into a compact unit. The units can be embedded in headgear of a user, allowing for hands-free operation of the system. Alternatively, the antenna transceiver system can be integrated into a vehicle, man-transportable backpack, or other designated platforms.

Abstract: A multibeam transmitting/receiving apparatus is provided that is capable of increasing the accuracy of a direction in which a transmission beam is to be transmitted, with a simple arrangement. Signal power measuring units (8-1 through 8-L) of signal processing means (40-1 through 40-L) measure reception signal power levels averaged over a given time, using outputs from reception beam formers (5-1 through 5-L), and indicate the measured reception signal power levels to transmission antenna weight generator (30). Transmission antenna weight generator (30) generates transmission antenna weights, which has been weighted by a reception signal level, from a transmission antenna weight corresponding to reception signal power level P1 and a beam number B1 of a finger having a maximum reception signal power level, and a transmission antenna weight corresponding to reception signal power level P2 and a beam number B2 of a finger having the same path timing as the finger having the maximum reception signal power level.

Abstract: A method of employing multipath propagation in wireless radio communications uses an omnidirectional transmitting/receiving antenna at one end of a transmission link to send an interrogating signal across an environment subject to multipath disturbances to a phase-conjugating retrodirective antenna, and the retrodirective antenna returns a communication signal along the multiple pathways taken by the interrogating signal to the omnidirectional antenna despite the multipath disturbances. In a simplex communication mode, the retrodirective antenna sends a return signal mixed with a communication signal to the omnidirectional antenna. In a duplex communication mode, both an omnidirectional antenna and a phase-conjugating retrodirective antenna are operated in tandem at each end of the transmission link to provide effective two-way wireless radio transmissions.

Abstract: A method for transmitting data from a transmitter to a receiver in an ad hoc large scale directional network includes the followings steps. A first training sequence is sent by a transmitter in an ad hoc directional network. The first training sequence is received by a receiver in the ad hoc directional network. The receiver determines a first apparent direction from which the first training sequence is sent. The receiver sends a second training sequence to the transmitter. The transmitter determines a second apparent direction from which the second training sequence is sent. The transmitter directs a signal with the first training sequence to the receiver. The transmitter sends the signal with the first training sequence to the receiver. The receiver receives the first training sequence. The receiver is directed to the first apparent direction to receive the signal.

Abstract: A high-directivity transponder system uses a dual system of a retrodirective array transmitting a data signal peak toward an interrogator source, and a self-null-steering array transmitting a null toward the interrogator source and a jamming signal elsewhere, resulting in high S/N reception at the interrogator source and avoidance of interception. Integrating modulators would allow each array to transmit different data while the spectra of the transmitted signals are identical, thus disabling interception. The system enables secure point-to-point communications and can be used for short-distance wireless data transmission systems such as wireless LAN and RFID servers.

Abstract: A reflector array antenna is divided into independent subarrays each comprising at least two radiating elements adapted firstly to collect signals delivered by a source and having at least one chosen first polarization and secondly to send phase-shifted signals having at least one chosen second polarization orthogonal to the first polarization. Each subarray sums the collected signals as a function of a chosen first phase law so that they correspond to a chosen source pointing direction, applies a chosen phase shift to the summed signals, and distributes the phase-shifted signals between the radiating elements as a function of a chosen second phase law so that the radiating elements of each subarray radiate them in a pointing direction of a chosen area. The combining and distribution are effected separately and the subarrays are therefore of a nonreciprocal type.

Abstract: An on chip diversity antenna switch includes a first switch, a second switch, a third switch, and a fourth switch. The first switch is operably coupled to a pin associated with a first antenna, to a transmit path and to receive a transmit receive (T/R) control signal. The second switch is operably coupled to the pin associated with the first antenna, to a receive path, and to receive the T/R control signal. The third switch is operably coupled to a pin associated with a second antenna, the transmit path, and to receive the T/R control signal. The fourth switch is operably coupled to the pin associated with the second antenna, to the receive path, and to receive the T/R control signal. Based on the T/R control signal, the first or second antenna is coupled to the transmit or receive path via a single switch.

Abstract: There is provided an antenna array apparatus using a GPS signal in a base station and a beamforming method thereof. In the antenna array apparatus, a GPS signal processor receives GPS position information from a mobile station and calculates the position information of the mobile station. A signal processor calculates a weight vector using the position information to form a transmission/reception beam. A transmission/reception beamformer forms the transmission/reception beam according to the weight vector.

Abstract: A high-directivity transponder system uses a dual system of a retrodirective array transmitting a data signal peak toward an interrogator source, and a self-null-steering array transmitting a null toward the interrogator source and a jamming signal elsewhere, resulting in high S/N reception at the interrogator source and avoidance of interception. Integrating modulators would allow each array to transmit different data while the spectra of the transmitted signals are identical, thus disabling interception. The system enables secure point-to-point communications and can be used for short-distance wireless data transmission systems such as wireless LAN and RFID servers. As another aspect, self-steering signal transmission is employed for randomly oriented satellites using circularly polarized, two-dimensional retrodirective arrays. Quadruple subharmonic mixing is used as an effective means of achieving phase conjugation when a high-frequency LO is not feasible or inapplicable.

Abstract: A method and apparatus for reducing the observed rate of change of the channel characteristics in a system with multiple antennas at a mobile terminal. The slowing down of the observed channel fluctuations is effectuated on the downlink by either calculating or receiving signals that have a similar Doppler shift, referred to herein as Doppler-compensatable signals, and processing one or more of the Doppler-compensatable signals to compensate for Doppler shift. The slowing down of the observed channel fluctuations is effectuated on the uplink by pre-compensating symbol streams with the Doppler shift associated with the direction in which they are transmitted, so that the observed Doppler shift of these signals when they are received is reduced or even eliminated.

Abstract: System and methods are disclosed for passively determining the location of a moveable transmitter utilizing a pair of phase shifts at a receiver for extracting a direction vector from a receiver to the transmitter. In a preferred embodiment, a phase difference between the transmitter and receiver is extracted utilizing a noncoherent demodulator in the receiver. The receiver includes antenna array with three antenna elements, which preferably are patch antenna elements aced apart by one-half wavelength. Three receiver channels are preferably utilized for simultaneously processing the received signal from each of the three antenna elements. Multipath transmission paths for each of the three receiver channels are indexed so that comparisons of the same multipath component are made for each of the three receiver channels. The phase difference for each received signal is determined by comparing only the magnitudes of received and stored modulation signals to determine a winning modulation symbol.

Abstract: A method and apparatus for reducing electromagnetic interference (EMI) and jamming in Global Positioning System (GPS) receivers operating on rolling or spinning platforms and/or environments is provided. An antenna system having a pair of diametrically-mounted elements provides interferometric cancellation for spatial and polarization nulling of interference signals. The antenna system, operating in conjunction with multiplexing and anti-jamming electronics, provides interference suppression for a GPS receiver connected thereto. Interference cancellation is provided in jamming and non-jamming environments by selectively employing spatial or polarization nulling of the interference signal.

Abstract: A system and method for automatically generating a return beam in the direction of a received beam. The inventive system (10) includes a phased array antenna (12) for receiving a radio frequency signal having a first wavefront from a first direction. In response to this signal, the invention (10) provides a second signal having a second wavefront. The second signal is a phase conjugate of the first signal and is transmitted in a reverse direction relative to the direction of the first signal. In the illustrative embodiment, the invention includes a plurality of phase conjugators each of which are disposed in a transmit/receive module and coupled to an associated radiating element. Each of the phase conjugators includes a mixer (60) having the input signal as a first input thereto. The input signal has a first frequency and a first phase.