Wireless SAW sensors reader: architecture and design

This paper describes a prototype burst transceiver operating in the industrial, scientific and medical band that can be used to power, interrogate and receive response from a wireless passive surface acoustic wave sensor. While the transceiver architecture for this system has been previously described, this paper focuses on the prototype construction and component and system level performance testing. Key performance factors for the transceiver include the isolation provided by various radio frequency (RF) switches, the appropriate switch timing, and the digitization and collection of burst response signals for further processing. The isolation provided by RF switches generates the signal burst, switches the transceiver from the transmission to receiving mode, and provide receiver isolation from the transmission signal and path. The measurements taken in testing the transmitter and receiver sections are presented. In addition, the frequency spectrum of the in-phase and quadrature signals obtained after digitization and data collection is shown and briefly described.