2019-847 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.

Patent:

A Wirelessly Powered Frequency-Swept Spectroscopy Sensor

Potential 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

Related Materials:

• Y. Sun and A. Babakhani, "A Wirelessly Powered Injection-Locked Oscillator With On-Chip Antennas in 180-nm SOI CMOS for Spectroscopy Application," in IEEE Sensors Letters, vol. 3, no. 7, pp. 1-4, July 2019, Art no. 5500704, doi: 10.1109/LSENS.2019.2926640.

State of Development:

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