Georgia Tech ECE Research Group
In this lecture of the Wireless Without Batteries series, we discuss the basics of modeling antennas in circuits –both in transmit mode and receive mode. Below is a reading list corresponding to the material.
WWB02: Antennas in Circuits for Energy Harvesting
Paper: C.R. Valenta, G.D. Durgin. “Survey of Energy-harvester Conversion Efficiency in Far-field, Wireless Power Transfer Systems.” IEEE Microwave Magazine. vol 14, no 4, June 2014. 10 pages.
Reading: WWB Notes on Antennas in Circuits
In the Spring term of 2017, I taught a graduate-level class at the Georgia Tech campus in Shenzhen, China. I have a set of rough videos for 19 lectures related to the topics of low-powered sensing, radio communications, and energy-harvesting. Below is the introductory lesson, along with the corresponding readings.
WWB01: Introduction; Computation and Power Trends
Paper: J.G. Koomey, S. Berard, M. Sanchez, H. Wong. “Implications of Historical Trends in the Electrical Efficiency of Computing”. IEEE Annals of the History of Computing. Jul-Aug 2011. pp 46-54.
Reading: WWB Introductory Notes and Perspectives
If all goes well, the NNU team that brought us MakerSat will be launching a new satellite mission early next year as part of a new NASA-funded project. The new satellite experiment, called RFsat, will have a unique RF energy-harvesting radio designed and built by the Georgia Tech Propagation Group. PhD student researcher Cheng Qi has built a one-of-a-kind microwave backscatter reader and tag-sensor combo that will drive the mission package.
The low-powered reader designed by our team deploys a sensor that unfurls a distance away from the spacecraft. The reader then energizes and receives backscatter information from the device using a 5.8 GHz transmission. Complete with generator, retrodirective antenna, and rectenna harvester, the radio package qualifies as the first microwave space-based solar power satellite ever tested — despite the somewhat limited 1m range. You have to start somewhere.
Check out the story of the November 2017 MakerSat launch by the NNU team here.
From the Georgia Tech Research Corporation, a nice summary of one of our lab’s patents, co-authored by Yenpao “Albert Lu” and Gregory Koo:
Inventors at Georgia Tech have developed techniques that can extend the range and the potential data rate of low-power communication. These techniques use multiple antennas at the transmitter, receiver, and RF tag and will soon allow the exchange of low data rates over long distances. The techniques have the capability to allow RF tags to return high powered signals with higher data rates back to a reader unit. This allows for the sweeping of an RF waveform through space so that passive radio devices may more effectively harvest energy and boost the collection of microwave power by an energy-harvesting RF tag using multiple antennas. Collectively, these techniques work together to enhance the range and reliability of RF tags.
Download the summary at 5147.