Georgia Tech ECE Research Group
Introductory lesson on the use of load modulation to transfer information from an antenna to a reader. The lecture describes how to construct a link budget given all of the realistic effects encountered in the terrestrial backscatter world.
WWB11: Modulated Backscatter
Paper: J.D. Griffin, G.D. Durgin. “Complete Link Budgets for RFID and Backscatter Radio.” IEEE Antennas and Propagation and Magazine, April 2009. 10 pages.
This Problem of the Day (PotD) post comes from a historically significant ECE test, from an RFID class that Manos Tentzeris and I developed 10 years ago. The question asks how a biased tunnel diode increases reflected power and range from a backscatter antenna. This idea of using an active, negative-resistance region device for backscatter has popped up in the patent literature from time to time, but Georgia Tech PhD Francesco Amato performed some of the first microwave backscatter measurements with his custom-built Quantum Tunnel Modulator (QTM) tag. This illustrated the feasibility of the idea, published in 2015. The use of a tunnel diode modulator for backscatter has been investigated by researchers in UI Chicago, Sweden, and more Sweden.
This fall term, Jake Smith was been named the 2018 winner of the 2018 William Brown Fellowship for his work on wireless power transfer. Jake is currently working on a microwave power transfer demo, building a rectenna for a 5.8 GHz system magnetron-based system. An ORS alum, Jake is also serving as a mentor for the ORS Haiti-RELAY team, which is bringing low-cost electrical solutions to the poor in developing countries. Jake received his BSEE in Spring 2018.
The William Brown Fellowship was established in 2013 at Georgia Tech by friends and family of William Brown, the father of wireless power transfer. This year, a generous grant from the Space Solar Power Institute is being used with the fellowship to fund a graduate research assistantship dedicated to wireless power transfer work.
We discuss the use of inductive loops in the transfer of information for RFID and NFC systems.
WWB10: Inductive Coupling for Communications
Paper: J. Fischer, “NFC in Cell Phones: The New Paradigm for an Interactive World.” IEEE Communications Magazine, June 2009.