Abstract: Described herein is a retroreflective underwater backscatter node comprising a receiver that receives an incoming acoustic signal from a first direction; a reflector that reflects back an incoming acoustic signal in a second direction; and a modulator coupled to the reflector to modulate the reflected incoming acoustic signal as a back-scattered signal. In some embodiments, the first direction and second direction are substantially the same such that the retroreflective underwater backscatter node retro-directs an incoming acoustic signal as a back-scattered signal and incoming and back-scattered acoustic signals propagate in the same but substantially opposite directions.

Abstract: Device, systems, techniques, and methods for mm-wave energy harvesting utilizing a Rotman-Lens-based rectenna system. An energy harvester system can include one or more antenna, a Rotman Lens having a beam port side and an antenna side in electrical communication with the one or more antenna, and a rectifier network in electrical communication with the beam port side of the Rotman Lens. The energy harvester system can also include a power combining network in electrical communication with the rectifier network and having an output. The rectifier network can include a plurality of rectifiers connected to the beam port side of the Rotman Lens. Further, each of the plurality of rectifiers can include a rectifying diode. The power combining network can include a plurality of bypass diodes.

Abstract: According to one aspect of the disclosure, a mobile augmented reality (AR) system can include: a receiver configured to receive radio frequency (RF) signals from one or more items located within an environment; a tracking module configured to generate tracking data responsive to a location of the system within the environment over time; a display device; and one or more processors configured to determine a location of at least one of the one or more items within the environment using the received RF signals and the tracking data, and generate a visual representation of the location of the at least one item for display on the display device.

Abstract: Localizing objects and determining their accurate position and orientation at considerable distances within densely cluttered environments poses a formidable challenge. This disclosure introduces a new approach utilizing ultralow-power frequency-divided backscatter beams on a single tag to enable azimuth estimation. The mm-wave system leverages a cross-polarizing Rotman lens and radar system for its implementation. Testing results for the system underscore the tag's ability to achieve precise localization over more than 10 m of range with a median error of 6.4 cm, while also accurately determining orientation with a mean absolute error of 3.6°. This disclosure not only addresses the pressing challenge of object localization and orientation detection but also lays a foundation for future advancements in extended-range sensing technology.

Abstract: An exemplary embodiment of the present disclosure provides a backscattering RFID system comprising: a combined oscillator and reflection amplifier circuit comprising a first tunnel diode having an anode and a cathode; and a biasing circuit in communication with the anode and configured to bias the first tunnel diode in a negative differential resistance region; wherein the combined oscillator and reflection amplifier circuit is configured to modulate a RF interrogation signal to produce a backscatter signal.

Abstract: The disclosed technology includes device, systems, techniques, and methods for mm-wave backscattering and energy harvesting systems utilizing a Rotman-Lens-based rectenna system. An mm-wave backscattering and energy harvesting system can include one or more antenna, a Rotman Lens having a beam port side and an antenna side in electrical communication with the one or more antenna, and a switching network in electrical communication with the beam port side of the Rotman Lens. The switching network can be configured to cause the system to operate in either a backscattering mode or an energy harvesting mode.

Abstract: Device, systems, techniques, and methods for mm-wave energy harvesting utilizing a Rotman-Lens-based rectenna system. An energy harvester system can include one or more antenna, a Rotman Lens having a beam port side and an antenna side in electrical communication with the one or more antenna, and a rectifier network in electrical communication with the beam port side of the Rotman Lens. The energy harvester system can also include a power combining network in electrical communication with the rectifier network and having an output. The rectifier network can include a plurality of rectifiers connected to the beam port side of the Rotman Lens. Further, each of the plurality of rectifiers can include a rectifying diode. The power combining network can include a plurality of bypass diodes.

Abstract: Described herein is a retroreflective underwater backscatter node comprising a receiver that receives an incoming acoustic signal from a first direction; a reflector that reflects back an incoming acoustic signal in a second direction; and a modulator coupled to the reflector to modulate the reflected incoming acoustic signal as a back-scattered signal. In some embodiments, the first direction and second direction are substantially the same such that the retroreflective underwater backscatter node retro-directs an incoming acoustic signal as a back-scattered signal and incoming and back-scattered acoustic signals propagate in the same but substantially opposite directions.

Abstract: A handheld system radio frequency identification (RFID) system for fine-grained RFID localization of an RFID target. Also disclosed is a mechanism for localizing RFID targets at all orientations through software-controlled polarization of two LP antennas. The system may detect an RFID target using a generated circularly polarized (CP) RF signal and accurately localize the RFID target using a generated linearly polarized (LP) signal. The disclosed systems and techniques discover and localize RFID concurrently and regardless of RFID target orientation.

Abstract: The disclosed technology includes device, systems, techniques, and methods for mm-wave energy harvesting utilizing a Rotman-Lens-based rectenna system. An energy harvester system can include one or more antenna, a Rotman Lens having a beam port side and an antenna side in electrical communication with the one or more antenna, and a rectifier network in electrical communication with the beam port side of the Rotman Lens. The energy harvester system can also include a power combining network in electrical communication with the rectifier network and having an output. The rectifier network can include a plurality of rectifiers connected to the beam port side of the Rotman Lens. Further, each of the plurality of rectifiers can include a rectifying diode. The power combining network can include a plurality of bypass diodes.

Abstract: Techniques and apparatuses are described that implement localization and health monitoring. With the use of multiple backscatter tags, a reader can be implemented with a single antenna and have a relatively small footprint compared to other systems that utilize antenna arrays or multiple readers. Also, the backscatter tags can be implemented as passive devices and located at fixed positions. In this way, a single power source can be provided at the reader, and target angular resolutions can be realized without the additional mechanical complexities associated with other moving systems. Additionally, the backscatter tags can be implemented using relatively low-cost commercial off-the-shelf hardware. As such, performance of the reader can be readily customized with the purchase of additional backscatter tags.

Abstract: According to one aspect of the disclosure, a mobile augmented reality (AR) system can include: a receiver configured to receive radio frequency (RF) signals from one or more items located within an environment; a tracking module configured to generate tracking data responsive to a location of the system within the environment over time; a display device; and one or more processors configured to determine a location of at least one of the one or more items within the environment using the received RF signals and the tracking data, and generate a visual representation of the location of the at least one item for display on the display device.

Abstract: The disclosed technology includes device, systems, techniques, and methods for mm-wave backscattering and energy harvesting systems utilizing a Rotman-Lens-based rectenna system. An mm-wave backscattering and energy harvesting system can include one or more antenna, a Rotman Lens having a beam port side and an antenna side in electrical communication with the one or more antenna, and a switching network in electrical communication with the beam port side of the Rotman Lens. The switching network can be configured to cause the system to operate in either a backscattering mode or an energy harvesting mode.

Abstract: An exemplary embodiment of the present disclosure provides a backscattering RFID system comprising: a combined oscillator and reflection amplifier circuit comprising a first tunnel diode having an anode and a cathode; and a biasing circuit in communication with the anode and configured to bias the first tunnel diode in a negative differential resistance region; wherein the combined oscillator and reflection amplifier circuit is configured to modulate a RF interrogation signal to produce a backscatter signal.

Abstract: The disclosed technology includes device, systems, techniques, and methods for mm-wave energy harvesting utilizing a Rotman-Lens-based rectenna system. An energy harvester system can include one or more antenna, a Rotman Lens having a beam port side and an antenna side in electrical communication with the one or more antenna, and a rectifier network in electrical communication with the beam port side of the Rotman Lens. The energy harvester system can also include a power combining network in electrical communication with the rectifier network and having an output. The rectifier network can include a plurality of rectifiers connected to the beam port side of the Rotman Lens. Further, each of the plurality of rectifiers can include a rectifying diode. The power combining network can include a plurality of bypass diodes.