Devices based on surface acoustic waves for temperature sensors

Abstract

Temperature dependences of the central frequency and intrinsic loss of delay line based on surface acoustic waves (SAWs) are measured in a temperature interval of 10–300°C for langasite acoustic line and two-input SAW cavity with the acoustic line made of black lithium niobate that have central frequencies of about 342 and 427 MHz, respectively, at room temperature. The application of such SAW devices in temperature sensors at temperatures of no greater than 300°C with the frequency-domain input signal is considered. A method for monitoring of minor temperature variations at a sensitivity of 0.001°C using SAW cavities with the acoustic line made of black lithium niobate is proposed and experimentally tested.