A Study of Quartz Temperature Sensors Characterized by Ultralinear Frequency-Temperature Responses

Abstmct-Theoretical and experimental research work on quartz temperalure sensors with doubly rotated cuts characterized by ultralinear frequency-temperature responses has been conducted. According to the experimental results, it is found that the new quartz temperature sensor has a linear frequency-temperature response and a larger frequencpsensitivity lo temperature than the ones of the previously reported. This sensor also has fast thermal time constants for the low temperature transients. NUSUAL climatic phenomena have recently had a most baffling effect on the agriculture, forestry, fishery, and industry all the world over. Therefore, it will be of much importance to make these phenomena well understood and try to present basic ideas that would hopefully lead to world-wide cooperation in coping with the problems. In meteorology, we take an interest in the three-dimensional precision and remote-sensing systems for the global temperature with respect to seawater and the atmosphere. We think that our study will be able to help establish part of those systems, for we have recently discovered a new quartz temperature sensor which exhibits a higher degree of frequency linearity over a wide temperature range compared with the previous types. What is more, it has to be pointed out that the electronic system around the temperature sensor will be much simplified without any device for linearization of frequencytemperature characteristics. The purpose of our research is to help design a sensor characterized by ultralinear frequency-temperature responses. In this paper some features of such sensors will be discussed in detail according to theoretical and experimental results. 11. THEORY Suppose a thin quartz crystal plate whose electrical, mechanical, and optical axes are defined as in the directions of x,, x?, and x3 axes, respectively, as shown in Fig. 1. We denote the direction normal to the main plane by polar