Substrates for zero temperature coefficient Love wave sensors

Abstract

Abstract-Microacoustic Love wave delay lines show high sensitivity to perturbations such as mass depositions on the wave-guide surface. Furthermore, because of their shear polarization, Love waves are ideally suited for liquid sensing applications. Using a Love wave delay line as feedback element in an oscillator allows the realization of viscosity sensors, and, using a chemical interface, chemical sensors, where the output signal is the oscillation frequency. To achieve a high effective sensitivity, the cross-sensitivity to temperature has to be kept low. We outline the proper choice of a material and especially focus on the influence of crystal cut and the major device design parameters (mass sensitivity and coupling coefficient) on the temperature coefficient of the sensor.

A Weak Form Nonlinear Model for Thermal Sensitivity of Love Wave Mode on Layered Structures

“…Apart from the experimental studies on the thermal sensitivities of Love waves on quartz substrates [4]- [6], several theoretical models have been investigated. Jakoby et al have numerically analyzed the rotated quartz cuts and guiding layer thicknesses for Love wave devices using the propagator matrix approach, and a zero temperature coefficient of frequency (TCF) Love wave device at 35 ℃ is obtained [7], [8]. Josse has derived the effective permittivity function of the film-substrate interface to study the frequencytemperature characteristics of Love wave devices without considering the internal stress of the substrate by the overlay.…”