An RFID system includes multiple antennas and uses amplitude and phase information of the RFID signals received by each antenna to determine the position of RFID tags in the vicinity. More than one antenna can receive the RFID signals during a single read cycle, enabling the RFID system to operate more quickly than a system that energizes antennas separately.

The subject matter discloses a method to determine a relative direction of a target RF transmitter, performed by a direction finding (DF) system comprising at least a pair of antennas having an electromagnetic-absorbing material between them, comprising conducting wireless communication between the target RF transmitter and each one of the antennas of the DF system, measuring the signal strength of the target RF transmitter received at each antenna, calculating the difference between the signal strength measured at each one of the antennas in the pair, and determining a relative direction of the target RF transmitter to be is the direction of the antenna within the pair of antennas in which the stronger signal was measured.

An antenna structure is disclosed that is well suited for use in dual- or multi-band wireless environments and sized so that it may be used in an antenna array for angle of arrival (AoA) detection. More specifically, an antenna may include a first antenna element, which may be an antenna element such as a patch antenna. The first antenna element is positioned in a first plane and positioned on first side of a substrate. On an opposite side of the substrate, a ground plane may be positioned in a second plane. The ground plane shapes the radiation pattern of the first antenna element to operate as a directional antenna. Sandwiched between the ground plane and the first antenna element is an intermediate antenna element constructed to act as a metamaterial that increases an effective distance between the ground plane and the first antenna element.

Systems and methods are provided for a digital beamformed phased array feed. The system may include a radome configured to allow electromagnetic waves to propagate; a multi-band software defined antenna array tile; a power and clock management subsystem configured to manage power and time of operation; a thermal management subsystem configured to dissipate heat generated by the multi-band software defined antenna array tile; and an enclosure assembly. The multi-band software defined antenna array tile may include a plurality of coupled dipole array antenna elements; a plurality of frequency converters; and a plurality of digital beamformers.

Systems and methods are provided for a digital beamformed phased array feed. The system may include a radome configured to allow electromagnetic waves to propagate; a multi-band software defined antenna array tile; a power and clock management subsystem configured to manage power and time of operation; a thermal management subsystem configured to dissipate heat generated by the multi-band software defined antenna array tile; and an enclosure assembly. The multi-band software defined antenna array tile may include a plurality of coupled dipole array antenna elements; a plurality of frequency converters; and a plurality of digital beamformers.

A method and apparatus is disclosed herein for acquiring and tracking a satellite signal with an antenna. In one embodiment, the method comprises a) perturbing one or more of roll, pitch and yaw angles of an antenna orientation to create variant orientations associated with a first search pattern; b) computing new scan and polarization angles, in response to perturbed roll, pitch and yaw angles, for each of the variant orientations; c) receiving a radio-frequency (RF) signal from a satellite for each of the variant orientations; d) generating one or more receiver metrics representing a received RF signal associated with each of the variant orientations; e) selecting, as a new orientation, one of the variant orientations based on the one or more receiver metrics; and f) repeating a)-e) with the new orientation with a second search pattern narrower than the first search pattern.

The subject matter discloses a method to determine a relative direction of a target RF transmitter, performed by a direction finding (DF) system comprising at least a pair of antennas having an electromagnetic-absorbing material between them, comprising conducting wireless communication between the target RF transmitter and each one of the antennas of the DF system, measuring the signal strength of the target RF transmitter received at each antenna, calculating the difference between the signal strength measured at each one of the antennas in the pair, and determining a relative direction of the target RF transmitter to be is the direction of the antenna within the pair of antennas in which the stronger signal was measured.

Methods and systems for spatial filtering transmitters and receivers capable of simultaneous communication with one or more receivers and transmitters, respectively, the receivers capable of outputting source directions to humans or devices. The methods and systems use spherical wave field partial wave expansion (PWE) models for transmitted and received fields at antennas and for waves generated by contributing sources. The source PWE models have expansion coefficients expressed as functions of directional coordinates of the sources. For spatial filtering receivers a processor uses the output signals from at least one sensor outputting signals consistent with Nyquist criteria representative of the wave field and the source PWE model to determines directional coordinates of sources (wherein the number of floating point operations are reduced) and outputs the directional coordinates and communications to a reporter configured for reporting information to humans. For spatial filtering transmitters a processor uses known receiver directions and source partial wave expansions to generate signals for transducers producing a composite total wave field conveying communications to the specified receivers. The methods and communications reduce the processing required for transmitting and receiving spatially filtered communications.

In accordance with various embodiments of the disclosed subject matter, a system, apparatus and method is configured to receive/process radio frequency emanations of a potentially threatening drone to generate therefrom a human-recognizable audio signal characteristic of the drone (i.e., a voice of the drone) so that a warfighter may be alerted to the activity of the drone and respond accordingly.

In accordance with various embodiments of the disclosed subject matter, a system, apparatus and method is configured to receive/process radio frequency emanations of a potentially threatening drone to generate therefrom a human-recognizable audio signal characteristic of the drone (i.e., a voice of the drone) so that a warfighter may be alerted to the activity of the drone and respond accordingly.