A tracking system comprising: a transmitter configured to steer an RF beam across a detection range, a passive RFID tag configured to be enabled for locating substantially when located in the center of the RF beam of the transmitter, and an RFID reader configured to detect the tag 104 once enable.

A method for use in verifying a location of an item aboard a vehicle is provided. The method includes receiving, by a transceiver device located in the vehicle, at least one radio frequency identification (RFID) signal. Each RFID signal is associated with an RFID tag of an item aboard the vehicle. The method additionally includes processing the at least one RFID signal and transmitting, by the transceiver device, the at least one RFID signal to a passenger compartment of the vehicle.

Metamaterials are employed with satellites, e.g., small satellites, to increase the observability of such satellites. Any type of suitable metamaterial can be used. In exemplary embodiments fractal-based patterns or structures may be used. A super scatterer having a metasurface is employed for the satellite and enhances the radar reflection for a given area of the satellite. Such detection can be used for monitoring and/or controlling the orbits of satellite space craft.

In some embodiments, a transmitter has a first mode and a second mode. The transmitter is configured to repeatedly send discrete first wireless signals carrying transmitter identification information uniquely associated with the transmitter in the first mode and to send a second wireless signal carrying the transmitter identification information in the second mode. A receiver is configured to receive a wireless signal of the first wireless signals such that the receiver is activated by the wireless signal of the first wireless signal and, in response to receiving the wireless signal of the first wireless signals, to send a third wireless signal carrying the transmitter identification information to the transmitter. The transmitter is configured to transition from the first mode to the second mode in response to receiving the third wireless signal and determining that the third wireless signal includes the transmitter identification information uniquely associated with the transmitter.

Described are examples of a method and a system for locating and identifying an object in a search space. The method may be used to determine the presence, identity and relative location of a consumable item. The method uses an array of RFID antennas to interrogate the search space in which one or more objects having an attached RFID tag may be present. The RFID antennas transmit RF signals into the search space and detect RFID reply signals from RFID tags. RFID antennas can be operated at different receiver sensitivity gains or transmit power gains to define additional cell locations within the search space. The identity and location of the objects is determined from the detected RFID reply signals. In various applications, the location is determined in a linear search space, a two-dimensional search space or a three-dimensional search space according to array configuration and gain implementation.

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.

Metamaterials are described which can be employed with satellites, e.g., small sats, to increase the observability of such satellites. Any type of suitable metamaterial can be used. In exemplary embodiments fractal-based patterns or structures may be used.

Metamaterials are described which can be employed with satellites, e.g., small sats, to increase the observability of such satellites. Any type of suitable metamaterial can be used. In exemplary embodiments fractal-based patterns or structures may be used.

In an Electronic Article Surveillance (EAS), a radio frequency identification (RFID) subsystem of an EAS system, can detect a presence of an RFID tag in an RFID interrogation zone associated with a boundary of a controlled area. The EAS system can first determine that the RFID tag is not authorized to leave the controlled area across the boundary. A radar subsystem of the EAS system can second determine, within a first window of time around the first detecting, whether an object in motion is associated with the boundary. The EAS system can alarm based upon both determining that the RFID tag is not authorized to leave the controlled area and determining that the object in motion is associated with the boundary.

A harmonic reflector circuit comprising an antenna connected to a non-linear circuit via a matching circuit, wherein the harmonic reflector circuit is configured to receive a signal at a receive frequency (fRX), and configured to transmit said received signal at a transmit frequency (fTX), where the transmit frequency is a multiple of the receive frequency, the harmonic reflector circuit wherein the receive frequency (fRX) is in an interval from a first frequency to a second frequency, where the first frequency is at least 800 MHz; and the second frequency is at least 34 MHz larger than the first frequency; the received signal is transmitted at the transmit frequency (fTX) with an output power (Pout) of at least 70% of the maximum available output power (Pmax).