A Battery-Less Wirelessly Powered Frequency-Swept Spectroscopy Sensor

Summary

UCLA researchers in the Department of Electrical and Computer Engineering have developed a wirelessly powered frequency-swept spectroscopy sensor.

Background

Wireless power transfer is in increasing demand as the development of network sensors and bio-implantable devices gain popularity. Integration of a vast network of sensors with miniaturized sensor nodes is essential to power minimally intrusive medical implants. Among current energy sources, far-field electromagnetic radiation performs better than near field inductive coupling due to larger operating distances and less path loss. However, large external antennas are needed by far-field RFID which can easily exceed 10 cm² in area, and cause interference from TX to RX. A far-field RFID systems with reduced size and improved performance is highly needed.

Innovation

UCLA researchers have developed a fully integrated wirelessly powered microchip with a small footprint of 2.47mm². The chip includes an energy-harvesting front-end, a power management unit, a super-harmonic injection-locked oscillator, and on-chip receiving and transmitting antennas. The chip was successfully developed and achieved a maximum operating distance of 8cm, a 22% locking range from 4 to 5GHz, and a phase noise of -93dBc/Hz at 100Hz offset. The large locking range allowed for spectroscopy measurements on a variety of materials and fluids.

Applications

• Medical implants: detection of bleeding, body fluidic, cancerous tissue, etc. 
• Industrial monitoring: detection of corrosion, crack, or change in the dielectric. 
• Consumer electronics: fingerprint detection, touch sensors, objects identification, etc.

Advantages

• Extended operating distance 
• Enhanced sensitivity 
• Reduced power consumptions from the duty cycle mode 
• Large locking range

State Of Development

Device prototyped and characterized. Proof-of-concept spectroscopy measurements performed on various materials and fluids.

Patent Status