A system for using thin and energy-autonomous backscatter tags and corresponding sensing nodes may operate with 24 GHz backscatter reflectarray tags having low power consumption. A digital beam steering, frequency-modulated continuous wave (FMCW) radar may be used for detection, localization, identification and communications. The tags may include environmental sensors that are used to modulate backscatter waves for data communications directed to a reader or may digitally modulate the backscatter transmissions without sensor data for independent localization of each tag in a network.

A method of operating a frequency modulated continuous-wave radar can include transmitting CHIRP signals from a plurality of antennas of the frequency modulated continuous-wave radar, receiving, via the plurality of antennas, signals including asynchronously modulated retro-directive signals from at least one remote radio frequency tag generated responsive to the CHIRP signals, generating difference Intermediate Frequency signals from the CHIRP signals transmitted and the signals received, and performing a first transform operation on the difference Intermediate Frequency signals to detect occurrence of the asynchronously modulated retro-directive signals in the difference Intermediate Frequency signals.

Present invention is a wireless device comprising a Van Atta array, said Van Atta array comprising a plurality of antenna pairs, each of said antenna pairs comprising two antenna elements electrically coupled by a signal path of pre-determined length. The wireless device further comprises a measurement unit, said measurement unit is adapted to perform electrical measurements between two measurement points. One of said two measurement points is located at a first pre-determined location on the signal path of one of the antenna pairs, and the other of said two measurement points is located on a second pre-determined location on the signal path of one of the other antenna pairs. The present invention is also a method for retro-reflection of an incident wave using a plurality of antenna pairs.

An identification device that provides identification information is described. This identification device includes a set of radar reflectors that reflect radar signals having a fundamental wavelength. The set of radar reflectors may be arranged in a pattern corresponding to the identification information. For example, the set of radar reflectors may be passive and retrodirective, where a given radar reflector reflects a radar signal back along its prior direction of propagation. Moreover, the pattern may include regions that reflect the radar signals and second regions that do not reflect or scatter the radar signals. During operation, the identification device may receive the radar signals, and then may selectively reflecting the radar signals using the set of radar reflectors to provide the identification information.

A Van Atta antenna array comprising a number of antenna elements electrically connected to operate as a Van Atta antenna array and fabricated on and within a substrate. Each antenna element has a number of patch elements fabricated on the top surface of the substrate, with the patch elements being interconnected by substrate integrated waveguides. The antenna array provides a two-dimensional retro-reflective surface, which makes it especially suitable for InSAR monitoring of infrastructures.

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.

A system for using thin and energy-autonomous backscatter tags and corresponding sensing nodes may operate with 24 GHz backscatter reflectarray tags having low power consumption. A digital beam steering, frequency-modulated continuous wave (FMCW) radar may be used for detection, localization, identification and communications. The tags may include environmental sensors that are used to modulate backscatter waves for data communications directed to a reader or may digitally modulate the backscatter transmissions without sensor data for independent localization of each tag in a network.

An apparatus is provided for transmission of RF signals between a transmitter and a receiver. The apparatus includes a transmitter comprising a first retroreflector having a first array of sub-wavelength retroreflective elements at one end of an open cavity for transmitting RF seed signals. The apparatus also includes a receiver comprising a second retroreflector having a second array of sub-wavelength retroreflective elements at an opposite end of the open cavity for receiving the transmitted seed signal, the transmitted RF seed signals being in form of a beam directed toward the receiver.

In a cellular communication system, particularly in a system using GHz frequencies, communication signals may become blocked by physical objects. As a result, communications may be disrupted or prevented. In a cellular system using beamforming and directional signal beams, a beam is tested prior to its use by sending a discovery signal over the beam, and by detecting any reflections of the discovery signal. A reflection may indicate the presence of a blocking object in the direction of the beam. By repeating this process using different directional beams, it is possible to produce a map of an area surrounding the base station, and to subsequently select or configure a directional beam for communicating with an individual user device. The process may also be used when selecting the antenna position and orientation for a new base station, by testing different alternatives and selecting an alternative that has relatively fewer blocking obstructions.

Systems and methods are provided for distortion redirection in phased arrays. In an electronic device configured for transmission and reception of signals and having a two-dimensional phased array, effects of distortion, corresponding to at least one processing function applied during communication of signals, on the communication of signals may be assessed, and based on the effects of distortion, one or more adjustments for mitigating the effects of distortion may be configured and applied during processing of signals. Assessing the effects of distortion may include determining one or more characteristics associated with the communication of the signals, where the one or more characteristics relate and/or are subject to the effects of the distortion, and assessing the effects of distortion based on the one or more characteristics.