Abstract: A system for detecting a moving object is provided. The system comprises a detector module having a first antenna and a second antenna separated by a baseline distance. The system also comprises a processing module configured to receive a first signal and a second signal from the first receiving antenna and the second receiving antenna, respectively. The processing module is further configured to determine a delay rate spectrum followed by a 2D FFT for the first signal and the second signal based on a cross-correlation function and an observation time period. The delay rate spectrum is then used to detect the moving object and determine its location in terms of latitude and longitude coordinates.

Abstract: A system for passive microwave remote sensing using at least one microwave radiometer includes a fixed body portion and a mobile body portion. The mobile body portion is configured for rotatably coupling with the fixed body portion for rotation about a rotation axis. The mobile body portion is configured for supporting the microwave radiometer therein such that the microwave radiometer rotates about the rotation axis when the mobile body portion is rotated about the rotation axis such that a polarization axis of the radiometer is aligned with an earth axis. The fixed body portion includes a motor mechanism for effecting rotation of the mobile body portion. In an embodiment, the mobile body portion includes a plurality of body section, each body section being configured for supporting a microwave radiometer therein. In another embodiment, each one of the plurality of body sections is configured to be interchangeably coupled with each other.

Abstract: An electronic device may be provided with wireless circuitry that is tested in a test system. The test system may include test probes. Circuitry under test may wirelessly transmit test signals. The test probes may receive the test signals at multiple locations. Circuitry may measure direct current (DC) voltages generated by the test probes and may convert the voltages to electric field magnitudes. A test host may process the electric field magnitudes to determine whether the circuitry under test exhibits a satisfactory radiation pattern. The test probes may include dielectric substrates and one or more dipole elements coupled to respective diodes. The dipole elements may include indium tin oxide (ITO) and may include first and second sets of orthogonal dipole elements. Transmission lines coupled to the dipole elements may include ITO and may form low pass filters that convert rectified voltages produced by the diodes into the DC voltages.

Abstract: In some embodiments, an antenna may include a plurality of reflectarray tiles and a frame including a plurality of frame elements coupled electrically and mechanically. The frame may be configured to conform to a shape of a surface. Each frame element may be configured to receive one of the plurality of reflectarray tiles. In some aspects, the plurality of reflectarray tiles may be illuminated directly or indirectly by a feed.

Abstract: A measurement method for increasing the effective size of a quiet zone is provided. The measurement method comprises the step of in the case that an amplitude and/or a phase distribution of the quiet zone is known, determining a set of correction factors on the basis of said amplitude and/or phase distribution of the quiet zone. Additionally or alternatively in the case that the amplitude and/or phase distribution of the quiet zone and an antenna radiating aperture location on a device under test are known, the device under test is centered in the middle of the quiet zone and the device under test is moved radially in at least one axis.

Abstract: Super-resolution modal imaging methods and devices are disclosed herein. One super-resolution modal imaging device includes an optical component provided to receive incoming radiation, a mode separating structure for separating the received incoming radiation into multiple modes, at least one output array, and at least one detector array having multiple array elements for measuring an energy level of each mode to construct an image of the received incoming radiation.

Abstract: A process and systems for constructing arbitrarily large virtual arrays using two or more collection platforms (e.g. AUX and MOV systems) having differing velocity vectors. Referred to as Motion Extended Array Synthesis (MXAS), the resultant imaging system is comprised of the collection of baselines that are created between the two collection systems as a function of time. Because of the unequal velocity vectors, the process yields a continuum of baselines over some range, which constitutes an offset imaging system (OIS) in that the baselines engendered are similar to those for a real aperture of the same size as that swept out by the relative motion, but which are offset by some (potentially very large) distance.

Abstract: Quantum resolution imaging methods and devices are disclosed herein. The quantum resolution imaging device comprises an optical component provided to receive incoming radiation, a mode separating structure for separating the received incoming radiation into multiple modes, and an imaging array having multiple array elements for measuring an energy level of each mode to construct an image of the received incoming radiation as it comes in contact with a surface of one of the array elements.

Abstract: There is provided an antenna arrangement. The antenna arrangement comprises a first antenna array and a second antenna array. Each antenna array comprises antenna elements of a first polarization and antenna elements of a second polarization. The two antenna arrays are arranged to collectively be fed four signals, such that the antenna elements of each polarization at each antenna array is fed a respective one out of the four signals. The signal as fed to the antenna elements of the second polarization of the second antenna array is phase shifted 180° with respect to at least one of the other signals as fed to the other antenna elements.

Abstract: A detecting assembly and method for identifying and tracking clouds in a zone of the sky being observed where some thermal-infrared flux emitted by the zone is collected and transmitted to a thermal-infrared detector, the detector including a sensor sensitive to the flux in a set band of wavelengths, a measurement of the actual temperature and actual relative humidity of the air at ground level is carried out and the vertical temperature and water vapor distribution is deduced therefrom, the dataset relating to the thermal-infrared signal emitted by a reference sky for the vertical temperature and water vapor distribution is stimulated or obtained, the dataset thus simulated or obtained is subtracted from the dataset measured by the sensor to determine if clouds are present in the zone, and the dataset thus obtained is processed in order to compute the optical thickness and/or altitude of each cloud in the observation area.

Abstract: In a wireless transceiver station having M antennas, designate an antenna as a target reference antenna (TRA) and for each antenna m other than the TRA: define N distinct paths from antenna m to TRA through zero or more intermediate reference antennas, N is two or more, each distinct paths has a distinct associated set of one or more antenna pairs; for each antenna pair of the sets, estimate an effective forward and backward channel response by sending calibration pilots forth and back between the antenna pair and calculate a reciprocity coefficient for the antenna pair using the estimated channel responses; for each of the N distinct paths, calculate a reciprocity coefficient estimate using the reciprocity coefficients calculated for the set of antenna pairs associated with the path; and combine the N calculated reciprocity coefficient estimates to produce a final reciprocity coefficient estimate for antenna pair (m, target reference antenna).

Abstract: Systems and methods are provided for tracking moving objects from a set of measurements. An estimate of a posterior probability distribution for a plurality of track states is determined from an estimate of the posterior probability distribution for a plurality of possible assignments of the set of measurements to a set of tracks representing trajectories of the plurality of moving objects and the set of measurements. A new estimate of the posterior probability distribution for the assignments is determined from the measurements and the estimate of a posterior probability distribution for the track states. A variational lower bound is determined from the new estimate of the posterior probability distribution for the assignments, the estimate of the posterior probability distribution for the track states, and the set of measurements. These steps are iteratively repeated until the variational lower bound is less than a threshold value.

Abstract: An outphasing transmitter includes a decomposition block, first and second power amplifiers, and a dual-polarized antenna in a phased array antenna panel. The decomposition block decomposes a composite input signal into first and second decomposed RF signals. The first and second decomposed RF signals are coupled to the first and second power amplifiers. The first power amplifier is coupled to a vertically-polarized probe, and the second power amplifier is coupled to a horizontally-polarized probe. A plurality of dual-polarized antennas may be utilized. The first power amplifier is coupled to each vertically-polarized probe; while the second power amplifier is coupled to each horizontally-polarized probe.

Abstract: An antenna detection system for detecting an antenna under test is provided. The antenna detection system includes a network analyzer and a test device. The test device includes: a first substrate; a second substrate parallel to the first substrate and carrying the antenna under test removably; and a standard antenna fixedly disposed on the first substrate to receive a test signal from a first port of the network analyzer and send a radiation signal according to the test signal. The antenna under test receives the radiation signal and sends a to-be-measured signal to a second port of the network analyzer. The network analyzer obtains a parameter according to the test signal and the to-be-measured signal and compares the parameter with a theoretical value calculated according to an operating frequency corresponding to the antenna under test and a constant interval to output a detection result of the antenna under test.

Abstract: System, methods, and other embodiments described herein relate to detecting markers on a roadway. In one embodiment, a method includes controlling a radar to transmit a scanning signal with defined characteristics. The radar is integrated with a vehicle that is traveling on the roadway. The method includes, in response to receiving a reflected signal resulting from the scanning signal interacting with the roadway, identifying the marker from the reflected signal according to an electromagnetic signature of the marker embodied in the reflected signal. The electromagnetic signature is a response induced within the defined characteristics of the scanning signal that is embodied within the reflected signal.

Abstract: A communications network comprises performance determination circuitry and link control circuitry. The performance determination circuitry is operable to determine performance of a microwave backhaul link between a first microwave backhaul transceiver and a second microwave backhaul transceiver. The microwave backhaul link backhauls traffic of a mobile access link. The link control circuitry is operable to, in response to an indication from the performance determination circuitry that the performance of the microwave backhaul link has degraded, adjust one or more signaling parameters used for the mobile access link. The link control circuitry is operable to, in response to the indication that the performance of the microwave backhaul link has degraded, adjust one or more signaling parameters used for the backhaul link in combination with the adjustment of the parameter(s) of the access link.

Abstract: An image pickup apparatus includes a first exterior member made of a conductive material, a second exterior member made of a nonconductive material, and an antenna covered by the second exterior member and configured to provide a wireless communication. The antenna includes a feeder configured to supply a current, an oscillator configured to oscillate the current as a radio wave, and an intermediate part located between the feeder and the oscillator. The feeder and the oscillator are farther from the first exterior member than the intermediate part.

Abstract: A system and method for locating objects using radio frequency identifiers is provided. Each object to be located by the user has an object unit attached thereto with a RFID transponder. The user carries a proximity unit with a RFID transponder and warning devices. The method comprises: -a controller receives the instruction to locate a specific object; the controller obtains RFID readings, from the main intermediate units associated with location areas, with information about the object units detected; -determining the location area of the object to be located; -sending information to the user about the location area; -detecting the presence of the proximity unit carried by the user when it is within the location area; -repeatedly obtaining, using readings of the RFID signal strength, information about the distance between the proximity unit and the object unit, reporting it to the user using warning devices.

Abstract: A selective low noise amplifier (LNA) comprising an input hybrid coupler receives a first input and a second input and to provide a first output and a second output; and an output hybrid coupler receives a first input and a second input and to provide for at least one output. A first amplifier and a second amplifier, each respective amplifier in first and second parallel paths are couple to and between the first output and the second output, respectively, of the input hybrid coupler and the first input and the second input, respectively, of the output hybrid coupler. A phase controller coupled to at least one of the first input and the second input of the output hybrid coupler delays signals from the first and second inputs of the output hybrid coupler to the at least one output of the output hybrid coupler. A method is also disclosed.

Abstract: A replaceable thrust generating structure for an air vehicle, which includes one or more mounts, which are attachable to the air vehicle, and a thrust generating structure attached to each of the one or more mounts, and wherein the thrust generating structure includes an NMSET element.

Abstract: An apparatus comprising a plurality of radiating elements and a plurality of surface wave feeds. Each radiating element in the plurality of radiating elements comprises a number of surface wave channels in which each of the number of surface wave channels is configured to constrain a path of a surface wave. A surface wave feed in the plurality of surface wave feeds is configured to couple a surface wave channel in the number of surface wave channels of a radiating element in the plurality of radiating elements to a transmission line configured to carry a radio frequency signal.

Abstract: A detection system includes a polarization analyzer that generates one or more null detection values if an object is sensed in a received millimeter wave (MMW) brightness temperature data set. The polarization analyzer analyzes a polarization parameter in the received MMW brightness temperature data set to generate the one or more null detection values. An object detector detects if the object is present based on a comparison of the one or more null detection values to a predetermined threshold. A singular value decomposition (SVD) unit is enabled by the object detector to decompose the MMW brightness temperature data set into a plurality of image layers. Each image layer includes at least one feature of a scene. An identification unit analyzes the plurality of image layers from the SVD unit to determine a shape or a location of the object from the scene.

Abstract: A WLAN terminal positioning apparatus includes a directional antenna module including a directional antenna, a first motor, and a second motor wherein the second motor is combined with a shaft of the first motor and the directional antenna is combined with a shaft of the second motor such that the directional antenna has a hemispherical search range, where an angle of the maximum signal strength of the signal received by the directional antenna from the WLAN terminal is measured while the first motor or the second motor is rotated, and an estimated physical position of the WLAN terminal is calculated using a directional direction of the directional antenna.

Abstract: A method and structure for a phased-array system. An orthogonal signal generator generates a plurality of signals C(i) that are orthogonal or near-orthogonal, meaning that a cross correlation between any two signals C(i) is lower than autocorrelation, and there is a plurality of phased-array antenna elements, each said antenna element providing a signal Sinp(i). A multiplier multiplies each signal C(i) with the signal Sinp(i) of a corresponding one of the plurality of phased array antenna elements.

Abstract: System and method for locating objects using radio frequency identifiers. Each object to be located by the user (5) has an object unit (4) attached thereto with a RFID transponder (61). The user (5) carries a proximity unit (3) with a RFID transponder (51) and warning means (52, 54, 55). The method comprises: —a controller (1) receives the instruction to locate a specific object; —said controller (1) obtains RFID readings, from the main intermediate units (2) associated with location areas, with information about the object units (4) detected; —determining the location area of the object to be located; —sending information to the user (5) about said location area; —detecting the presence of the proximity unit (3) carried by the user (5) when it is within said location area; —repeatedly obtaining, using readings of the RFID signal strength, information about the distance between the proximity unit (3) and the object unit (4), reporting it to the user (5) using warning means (52, 54, 55).

Abstract: An altimetry system for a satellite, including an altimeter transmitting and receiving signals on at least one first frequency band; a radiometer receiving signals on at least one second frequency band, the altimeter and the radiometer being connected to one and the same antenna; reception means common to the altimeter and to the radiometer, and capable of amplifying and filtering the signals received from the antenna on a frequency band including the first frequency band and the second frequency band; means for separating the signals on the first frequency band from the signals on the second frequency band; the signals on the first frequency band being exploited to estimate an altimetric distance of the satellite, and radiometric measurements being exploited in order to correct the estimate.

Abstract: An antenna RSSI meter includes a microcontroller unit for digitizing an antenna receiver voltage signal, converting the digitized antenna receiver voltage signal into a receiver signal level in accordance with a predefined antenna specification, and converting the receiver signal level into the antenna tuning signal in accordance with the predefined antenna specification. The antenna RSSI meter includes an input communication port for receiving the antenna receiver voltage signal from an antenna and providing the antenna receiver voltage signal to the microcontroller unit, The antenna RSSI meter also includes an output communication port for receiving the antenna tuning signal from the microcontroller unit and providing the antenna tuning signal to an antenna auto-aligning mechanism for adjusting position and orientation of the antenna.

Abstract: According one embodiment, a millimeter-wave radiation imaging array includes a plurality of antenna elements configured to receive millimeter-wave radiative input. Each lenslet of a plurality of lenslets are coupled to one of the plurality of antenna elements such that no air exists between each lenslet and the one of the plurality of antenna elements. Each lenslet has a spherical portion being operable to direct the radiative input towards the one of the plurality of antenna elements. An energy detector is coupled to the plurality of antenna elements opposite the plurality of lenslets and operable to measure the radiative input received by the plurality of antenna elements.

Abstract: Systems and methods are disclosed for locating signal wave (SW) emitter/s using at least one moving signal collection platform. The disclosed systems and methods may be employed in one embodiment to estimate the signal energy transmitted from a grid of locations (such as a map) using collected IQ data (or other raw data representation such as IQ data covariance matrix), and without requiring computation of any intermediate geolocation-observable measurements (such as angle-of-arrival, direction-of-arrival, etc.). In a further embodiment, the disclosed systems and methods may be implemented in a blind manner (i.e., transmitted emitter signal/s are unknown and processed blindly) to geolocate SW emitters using a single SW signal collection platform (e.g., at relatively large standoff distances in some implementations) without relying on a known signal modulation or operation of multiple simultaneous SW signal collection platforms.

Abstract: There is provided a method for positioning of user equipment. The method for positioning of user equipment, includes: receiving, by the user equipment, a signal from an external antenna, the signal being radiated in a cyclic pattern; measuring, by the user equipment, strength of the received signal, characterizing, by the user equipment, the measured strength to form a signal pattern over a time period; and determining a position of the user equipment based on the signal pattern.

Abstract: A system and method is shown for receiving microwave/millimeter-wave signals. The system and method are balanced and can be effectively implemented on a silicon substrate using single pole double throw switches.

Abstract: A calibration device, capable of calibrating a gain of a radiometer, includes an actuator and a micro-electromechanical-system (MEMS) unit. The actuator receives a calibration signal outputted from a control unit. The MEMS unit is coupled to the actuator, in which the actuator enables the MEMS unit to shield an antenna of the radiometer according to the calibration signal, such that the radiometer generates an environmental signal according to an equivalent radiant temperature received from the MEMS unit, and the control unit calibrates the gain of the radiometer according to the environmental signal.

Abstract: A direct-to-home satellite outdoor unit may comprise a reflector, a support structure, circuitry, and an array of antenna elements mounted to the support structure such that energy of a plurality of satellite beams is reflected by the reflector onto the array where the energy is converted to a plurality of first signals. The circuitry may be operable to process the first signals to concurrently generate a plurality of second signals, each of the second signals corresponding to a respective one of the plurality of satellite beams. The circuitry may be operable to process one or more of the second signals for outputting content carried in the one or more of the second signals onto a link to an indoor unit.

Abstract: An Antenna Mode Steering (AMS) method in a signal receiving apparatus using at least one antenna is provided. The method includes measuring a received signal quality of a signal received through the at least one antenna for each of antenna modes available in the signal receiving apparatus, and selecting a specific antenna mode from among the antenna modes as an antenna mode to be used in the signal receiving apparatus based on the measured received signal quality.

Abstract: A photovoltaic (PV) panel is described that can be used in a PV installation, in cooperation with a central control unit to provide a map of locations of individual PV panels. The map can be determined by the central control unit based on measurements of a characteristic made at the plurality of PV panels. The characteristic provides an indication of adjacent PV panels, allowing the map of locations of individual PV panels to be constructed.

Abstract: A system for engaging hostile air or space threats with a defensive missile, where the defensive missile comprises an antenna for receiving global positioning system (GPS) signals. A global positioning system receiver is coupled to said antenna, for receiving global positioning system signals directly from global positioning system satellites and global positioning system signals reflected from the threat. A processing arrangement processes the direct and reflected global positioning system signals for determining the position and velocity of the threat. Vectoring controls are coupled to the processing arrangement, and are responsive to the location of the threat for directing the defensive missile toward the threat. In a particular embodiment, the antenna of the defensive missile is directionally controllable, and the defensive missile includes an antenna direction controller responsive to the processor for directing at least a beam of the antenna toward the threat.

Abstract: A method of operating a multi-function phased array radar system having an antenna array populated with dual-pol antenna elements is described. The method includes selectively controlling individual dipoles of each dual-pol antenna element in order to operate the array in either a polarimetric mode with improved cross-pol isolation, or in a multi-mission mode, wherein a plurality of singularly-polarized signals are produced.

Abstract: An apparatus for allocating a current measurement value for a geographical position to a map object of a geographical map, wherein the current measurement value originates from a series of adjacent measurement values for adjacent geographical positions, having a processor for determining a first probability measure indicating whether the current measurement value can be allocated to a first map object to which at least one adjacent measurement value of the series has already been allocated previously, and for determining a second probability measure indicating whether the current measurement value can be allocated to a second map object having an intersection with the first map object, if the first probability measure indicates that an allocation of the current measurement value to the first map object is unlikely.

Abstract: A signal processing method performs operations of coherent processing making it possible notably to purge the useful signal of the spurious signals (in particular the reference signal and its multiple reflections), to regenerate the transmission signal and to perform a coherent integration of the signal received by computing the cross-ambiguity between the signal received and the regenerated transmission signal. It also performs operations of non-coherent processing making it possible in particular to carry out extraction and Doppler distance purification operations making it possible to form blips and to eliminate the spurious blips present among the blips formed. The method applies notably to passive radars operating on non-cooperating opportunity transmissions, such as FM transmissions intended for the public.

Abstract: A technique for determining the position of a device involves generating a set of N measurements from signals transmitted by a respective set of N references devices, where the N measurements are suitable for determining a position of the device using N-lateration. Respective reliability metrics are generated for the N measurements based on information about uncertainty of individual measurements. An N-lateration computation is used to iteratively refine an estimate of the position of the device. Each iteration includes adjusting the estimate of the position of the device based on a least squares function that minimizes a sum of squares of errors between the N measurements and distances between the estimate of the position of the device and the N reference sources. The least squares function is weighted in accordance with the reliability metrics for the N measurements.

Abstract: The present invention relates to a radiometric imaging device and a corresponding method for scanning a scene. The proposed device comprises a radiometer configured to detect radiation in a predetermined spectral range emitted from said scene and to generate a radiation signal from said detected radiation, and a processor configured to process said generated radiation signal by de-convoluting said generated radiation signal by use of a distance-dependent de-blur kernel, which is determined depending on the distance between said scene and the radiometer. This effect is dominant in the non-reactive near-field of the antenna. Due to the distance-dependent de-convolution a significantly improved image quality can be achieved.

Abstract: An altimetry method comprising: providing a signal receiver (RX) on a first platform (S1) flying above a portion of the Earth surface (ES), for receiving a temporal series of signals emitted by a second flying platform (S2) and scattered by said portion of the Earth surface; and computing altimetry waveforms, indicative of an elevation profile of said portion of the Earth surface, by processing the received signals; characterized in that said step of computing altimetry waveforms comprises: cross-correlating the received signals with a plurality of locally-generated frequency-shifted replicas of the emitted signals; introducing a frequency-dependent temporal shift to the correlation waveforms in order to compensate for range delay curvature; and incoherently summing the temporally shifted correlation waveforms (CXC) corresponding to signals scattered by a same region of the Earth surface at different times during motion of said first platform.

Abstract: Improved methods and apparatuses are provided to address a potential “hidden beam problem” in wireless communication systems employing smart antennas. The improved methods and apparatuses utilize complementary beamforming (CBF) techniques, such as, for example, Subspace Complementary Beamforming (SCBF), Complementary Superposition Beamforming (CSBF) and/or Single Beam Complementary Beamforming (SBCBF) techniques.

Abstract: A radiometer for measuring temperature data can include a data reader for reading target data associated with a measurement target and generating temperature data based on the target data. A temperature compensation system can include a radiometer with a data reader and one or more data tags placed proximate corresponding measurement targets. The data tags can contain target data including a target identifier and/or compensation data, among other data. The compensation data can include, for example, a target emissivity. In some embodiments the data reader can include an optical scanning device and/or an RFID reader.

Abstract: A MMIC includes at least one quadrature hybrid in a plurality of series connected amplifiers connected in two parallel gain stages and operatively connected to the at least one quadrature hybrid such that gain is equalized in the two parallel gain stages.

Abstract: A receiver includes a detector configured to detect a signal and output an output signal, a state section configured to control the signal inputting into the detector according to a level of a control signal, an edge section configured to discard the output signal of the detector while detecting an edge of the control signal, and leave the output signal of the detector while not detecting the edge of the control signal, a high/low level section configured to multiply the output signal which is left by the edge section by a first coefficient while the level of the control signal is high, and multiply the output signal which is left by the edge section by a second coefficient while the level of the control signal is low, and an adding section configured to output a first signal multiplied by the first coefficient and second signal multiplied by the second coefficient.

Abstract: Methods and systems for detecting an energy emission event are provided. In a method for detecting an energy emission event, a reference event signal is compared with a received event signal. In some embodiments, the reference event signal is associated with radiated energy having a predetermined temporal response. A detection signal is output when the received event signal corresponds to the reference event signal. In response to outputting the detection signal, imagery of a location in proximity to where the received event signal originated is captured or processed. Using the captured imagery and the detection signal, a determination of where the received event signal originated is made.

Abstract: A space-borne interferometric radiometer for imaging a radiation emission from a target scene (ED), comprising a plurality of receiving elements arranged in a two- or three-dimensional array (REA), a first signal processor (SP1) for computing a two-dimensional set of samples of a visibility function by pair-wise cross-correlating signals received by the receiving elements; and second signal processor (SP2) for reconstructing an image from the samples of the visibility function. The radiometer is further characterized in that it has the ability for rotating the two- or three-dimensional array (REA) about a rotation axis (z) which is substantially directed toward the target scene (ED) and in that the second signal processor (SP2) is adapted for reconstructing the image from a plurality of two-dimensional sets of samples of the visibility function corresponding to different rotational positions of the rotating two- or three-dimensional array (REA) of receiving elements.

Abstract: A radiometer imaging system includes an antenna array having a plurality of sub-arrays, each being formed of a plurality of antenna elements arranged in a sub-Y-type, a receiver array having the same number of receivers as the antenna elements, each receiver being associated with one of the antenna elements in a one-to-one correspondence to thereby define a channel to generate a first signal and a second signal from an output of each antenna element, and a correlation processor for calculating a correlation for each correlated channel pair, by using the first signal and the second signal for each antenna element, to thereby obtain an 3-D image for the object.

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.