A remote wireless identification system based on passive surface acoustic wave (SAW) devices

A wireless identification system, based on passive surface acoustic wave (SAW) devices, is presented in this paper. Because the system operates at 915 MHz center frequency, we employ a pair of SAW dispersive delay lines to expand and compress the signal. Using this method, we can enhance the processing gain and filter the noise out of the bandwidth. Thus, we can decrease the demands of the receiver sensitivity and improve the system's performance in rejecting interference signals. The testing results show that the maximum readout distance of the interrogator is 20 m.