A passive coding resonant wireless SAW temperature sensor array

Abstract

This paper proposes a passive coding resonant SAW wireless sensor for the purpose of constructing a sensor array or multiple sensor system. The sensor consists of a SAW delay line, a SAW resonator and a necessary passive impedance match between the two SAW devices. The SAW delay line is used to code the sensory element for identification through its delay time and the resonator functions as a sensory cell. A sensor array consisting of such sensory cells can operate in the frequency band just for a single sensor. The delay time can be designated in a rather wide range so that the array can address as many as required sensory cells simply by time-division through delay time. A single sensory cell consists of different kinds of SAW devices, and the devices may be integrated together on a single piezoelectric substrate in manufacturing or may be simply combined together using separate devices. Thus the scheme provides the flexibility and simplicity to organize an array or a multiple sensor system.