Key Technologies of Passive Wireless Sensor Networks Based on Surface Acoustic Wave Resonators

In this paper, we present the passive wireless sensor network based on the surface acoustic wave(SAW) resonators. The sensor node consists of the SAW sensor that is small, light, reliable, stable, sensitive, wireless and passive, so the battery is needless and its life-span is infinite. The sink node gathers data from the sensor nodes, processes the data with intelligent algorithms and transmits the needed data to the exterior network timely. The basic structure and the realization of the passive wireless sensor network are elaborated. The five main characteristics of the passive wireless sensor network, that is passive sensor nodes, simple and small sensor nodes, organized sensor nodes, intelligent sink nodes, high security, good extendibility, are explained concretely. Specially, the key techniques in our research, such as coding and decoding techniques of the sensor node, signal frequency measurement techniques of the sensor node, intelligent signal processing techniques, measurement error compensation techniques and network security techniques, are discussed exhaustively. In the end, we point out the problems at present and forecast the application prospect and research direction in the future.