ESL Student Seminar: Integration of Radio Frequency Harvesting with Low Power Sensors

Presented by Brock J. DeLong

All dates for this event occur in the past.

ElectroScience Laboratory, MRC Conference Room
ElectroScience Laboratory, MRC Conference Room
1330 Kinnear Road
Columbus, OH 43212
United States

Please join us for a seminar presented as part of our ESL Student Seminar Series. FREE PIZZA and refreshments will be provided!

 

Abstract

This work follows the footsteps of Nikola Tesla in the modern pursuit of wireless power for small devices, e.g. sensors. Guidelines are given on making state-of-the-art power harvesters and optimizing its components for a given application, such as its recti er, matching network, and antenna. Several experiments take place over the course of this work. Various devices are charged and powered up, including a clock, computer mouse, calculator, thermometer, medical insulin pump, and a supercapacitor.

An array of rectifying antennas (rectennas) is produced and developed for a novel experiment involving wireless power transfer over very long distances, viz. up to 60 meters. Bandwidth widening techniques are also discussed, including a design with a 25% bandwidth. Further investigation into optimizing the recti er is performed. Using a quarter-wave rectifying circuit with a single diode, an efficiency of 73.7% is measured. We go on to compare this rectifier with other rectifiers, ending that indeed that quarter-wave rectifier is the most efficient in its power range and frequency. A novel quarter-wave rectenna is developed and tested as well. Wireless power transfer in close proximity, viz. the radiating near- eld, is also demonstrated in this work. Using RF harvesters in the radiated near- eld, we show a strong tolerance to misalignment while delivering high levels of power (1.2 mW over 42 cm). A medical pump is successfully powered over this distance. Miniaturization of the rectenna reduces the overall dimensions down to 1.5 x 2.5 cm^2, making it ideal for medical or on-body applications. This rectenna was used to successfully activate a body-worn thermometer across 65 cm. At the end of this study, various aspects are presented in regards to implantable devices for wireless power transfer. The concept of a dielectric matching layer for rectennas is presented and validated using pig skin, concluding with a SAR analysis for safe operations.

 

Bio

Brock J. DeLong (M’15) was born in Van Wert, OH, on September 4, 1991. He received the B.Sc. degree in Electrical and Computer Engineering (summa cum laude) in 2014 from The Ohio State University, Columbus, OH, USA. He is currently pursuing the Ph.D. from The Ohio State University. His research interests include wireless power transmission, medical devices, and millimeter-wave antennas. He has previously worked as an Automation Engineer with Eaton Corporation, an Advanced High Frequency Engineer with NASA Glenn Research Center, and is currently a Graduate Research Associate at the ElectroScience Lab (ESL) of The Ohio State University.