The authors of this original paper have been leading this work on backscatter and even have a long range backscatter system that gives ranges of a kilometer. Th

The authors of this original paper have been leading this work on backscatter and even have a long range backscatter system that gives ranges of a kilometer. They also have a startup commercializing backscatter. https://www.jeevawireless.com/ https://www.jeevawireless.com/ http://longrange.cs.washington.edu/ http://longrange.cs.washington.edu/