Georgia Tech ECE Research Group
2007: Josh Griffin lead authors the immensely influential paper on the use of multiple antennas in a backscatter link for readers and tags. His work predicts big gains in both data rate and reliability.
Josh Griffin develops the theory of multi-antenna backscatter which forms the backbone of his PhD work. Highly original and highly cited, the work has led to a number of subsequent investigations into the potential for multi-antenna backscatter systems. [Read more…]
2006: Anil Rohatgi builds a 915 MHz spread spectrum multi-tag system that demonstrates polarization and space diversity in a real backscatter communications link.
This 2006 experiment was a landmark for many reasons. It was the group’s first foray into coding theory for backscatter systems. It also garnered an invite to the 2008 IEEE RFID conference in Las Vegas … a relationship that has turned surprisingly long-term.
Tunnel Diodes for Backscattering CommunicationsThe authors give an overview about the research progresses done in the latest years to enhance ranges of microwave backscattering communications with RFIDs exploiting the tunneling effect of tunnel diodes. The first prototype of a Tunneling RFID Tag built using a tunnel diode outperformed semi-passive tags by at least a factor of 5 in range. Tests on the 5.8 GHz backscattering link reached 1.5 km of ranges and demonstrated that a DC power of only 20.4 μW and 2.9[pJ/bit] are required to operate the Tunneling Tag.
915 MHz RF Downconverter: Albert Lu builds the group’s first direct downconversion receiver box for backscatter, allowing ground-breaking experiments and a template for operating at higher frequencies.
This direct downconversion hardware at 915 MHz produced a filtered baseband IQ receiver output that enabled the first round of serious backscatter modulation experiments by the group. Deigned by Albert Lu, it was a prelude to the microwave hardware that would constitute the 5.8 GHz backscatter system.