Design and temperature sensor based on saw transducer

Abstract

In this work, we modeled an experimental study of a surface acoustic wave temperature sensor by a numerical simulation using the finite element method (FEM) under the Comsol multiphysics tool, this sensor based on the piezoelectric material which is AlN with two configurations Pt/AlN/Si and Pt/AlN/Pt/Si, these temperature sensors operate at temperatures up to 500°C. The results show that the central frequency of the resonator at room temperature is 445 MHz, the variation of this frequency with temperature is linear, and the value of the temperature coefficient for frequency (TCF) is -40.54 ppm/°C. This shows good temperature sensitivity, and makes it suitable for temperature sensing and measurement applications. The electromechanical coupling coefficient (k 2 ) increases with temperature and a linear relationship is observed. the temperature coefficient of k2 is 821 ppm/°C calculated from the linear fit. The value of k 2 is 0.35% at room temperature, and it increases to 0.37% at 500°C. We have also investigated a configuration of a SAW delay line operating in the time domain with a view to its use in wireless sensor applications. Keywords: Sensors, MEMS, Design, SAW Transducers