New Cuts of Quartz for Surface Transverse Wave Temperature Wireless Sensors

Abstract

A surface transverse wave (STW) in quartz is interesting for application at high frequencies because of higher velocity than that of a surface acoustic wave (SAW). STW propagates along the plane of Y rotated cut perpendicularly to X axis of quartz and is described as θYX90 o , where θ is rotation angle. The plane should be covered with periodical electrodes and period of electrodes p should be equal to λ/2, where λ is the STW wavelength. So far, the STW were investigated only for the temperature compensated cut at θ ≅ 36 o . In this work we experimentally investigated three cuts with expected high first order temperature coefficients of frequency (TCF 1 ). For θ ≅ 43 o (ST cut for SAW propagating in the X direction), TCF 1 ≅ 35 ppm/ o C, was obtained. However, the second order coefficient TCF 2 ≅ -53 ppb/ o C 2 introduced relatively large nonlinearity to the frequency changes against temperature. For the new cuts at θ ≅ 47 o and θ ≅ 55 o , the TCF 1 of about 45 ppm/ o C and 71 ppm/ o C respectively, were obtained. TCF 2 = 0 was obtained for both cuts. The results show that the STW on the new cuts of quartz are attractive for application in wireless temperature sensors.