In this lecture, we review the nature and properties of piezoelectric devices and discuss how them may be used to make RF surface acoustic wave devices.  RF SAW devices, already commonplace in consumer electronics,  have a number of novel, low-power radio applications in the field of sensing and RFID.

WWB17:  RF SAW Devices

Paper:  Victor P. Plessky and Leonhard M. Reindl, “Review on SAW RFID Tags”, IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, vol. 57, no. 3, March 2010.

Although there are many radio links that benefit from a backscatter configuration, a conventional one-way radio link often proves more beneficial. Below are eight beneficial attributes that engineers consider when choosing a backscatter link over a one-way radio link: [Read more…]

Chris Valenta designed the R.E.S.T. platform, a modular 5.8 GHz backscatter platform with a software radio reader that could be configured for a limitless combination of sensors, antennas, power sources, and modulation schemes.

The R.E.S.T. (RFID-Enabled Sensing Testbed) was published as a flexible development platform that allowed the group to experiment with all sorts of 5.8 GHz application platforms.  It was the quintessential low-power, microcontroller-based backscatter system.

Fun fact: although they did not exactly use the original R.E.S.T hardware, future group applications — the helmet shock sensor, the motion capture experiments, the ATM terminal protection system, and others — were based on the R.E.S.T.’s architecture.