Surface Acoustic Wave Pulsed-Correlator Transceiver for Aerospace Applications

This paper will present current efforts on wireless passive surface acoustic wave (SAW) sensor transceiver development for aerospace applications. Our group\u27s SAW sensor work has been sponsored by NASA for the past ten years in efforts to develop wireless sensing for ground base and space exploration in extreme environments. The devices are radiation hard and work from cryogenic to several hundred degrees centigrade with standard device processing. The focus of this paper will be on a synchronous, pulsed correlator transceiver for interrogation of SAW delay-line sensors. The 915-MHz system has a bandwidth of 15 MHz and uses a pulsed noise-generated signal of 1-mu s duration. The design principles, system analysis, and receiver measurements are given. The prediction of signal-to-noise ratio versus range is shown for given system parameters. The system development leading to the first testing of SAW liquid level sensors at NASA KSC will be discussed