Stewart J. Thomas

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Passive and semipassive UHF RF identification (RFID) systems have traditionally been designed using scalar-valued differential radar cross section (DRCS) methods to model the backscattered signal from the tag. This paper argues that scalar-valued DRCS analysis is unnecessarily limiting because of the inherent coherence of the backscatter link and the(More)
This paper presents a digital neural/EMG telemetry system small enough and lightweight enough to permit recording from insects in flight. It has a measured flight package mass of only 38 mg. This system includes a single-chip telemetry integrated circuit (IC) employing RF power harvesting for battery-free operation, with communication via modulated(More)
We describe a radio frequency (RF) energy harvester and power management circuit that trickle charges a battery from incident power levels as low as -20dBm. We designed the harvester for the 2.4 GHz RF band to leverage the ubiquity of energy that is produced by Wi-Fi, Bluetooth, and other devices. This paper reports on the design and current status of the(More)
The harsh construction environment requires unusually robust sensing and actuation technology to make real-time pro-active safety alerts a reality. We have developed a batteryless, wireless sensing and actuation device as an option to advance pro-active safety in construction. By employing electromagnetic energy harvesting and eliminating the need for a(More)
Wearable and implantable wireless biomedical devices are often constrained by the limited bandwidth and high power consumption of their communication links. The VHF or UHF transceivers (e.g. MICS radios) traditionally used for this communication function have relatively high power consumption, on the order of mW, due to the high bias currents required for(More)
This paper concerns the use of wideband RF backscatter from semi-passive RF tags for energy-efficient wireless telemetry. Using LFM (Linear Frequency Modulated) signals from a radar base station, we present a method for joint ranging and communications with a distributed set of sensor nodes. Backscatter signaling from each node results in modulation on a(More)
This paper considers the adaptation of frequency modulated continuous wave (FMCW) radars for sensor data exfiltration in addition to their primary use in area surveillance. In particular, the application of wideband RF backscatter from semi-passive RF sensor nodes for simultaneous ranging and wireless telemetry uplink to an FMCW radar is examined. We(More)
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