I thought this technology sounded familiar...I wrote about it in September: http://www.designnews.com/author.asp?section_id=1386&doc_id=267327 But I think your story takes a slightly different approach and talks about some aspects of the technology I didn't cover, so it's still relevant!
Cabe, the approach you mention is just the way RFID tags work. In the case of RFID a device, the reader, sends out a signal and, for passive RFID tags, the energy is used to power the tag and respond with the information. That is not to say that this is a great idea. As your article points out, in populated areas we are inundated with RF signals. Of course, the people who are against smart meters, for example, which often use WiFi, say that it is the meters that cause them medical problems. One of the types of energy we have in abundance in the air is WiFi signals. This research shows that there is a lot more than the meters energizing the environment around us.
California State University, Chico was the first school in California to offer an ABET-accredited degree program in mechatronic engineering. Now its California Mechatronics Center works with industry on machinery, robotics, and surveillance vehicles.
Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.