The temperature range limitation of passive, wireless monitoring by surface acoustic wave device

There were many studies devoted to SAW passive, wireless temperature monitoring. There are two ways to implement SAW passive, wireless temperature monitoring: through time domain and through frequency domain. Most researches utilized the time domain approach, on behalf its accompanied identification function. For time domain approach, it is necessary to use the phase information for judging the temperature so as to reach enough precision. However, in order to have an exclusive measuring value, there exists a temperature range limitation, which is related to the error for used system, required reliability, the permitted frequency band, and the needed temperature accuracy. It is important to note it when people want to monitor an object in a wide temperature range. In this paper, the relation among the temperature range and the error, required reliability, the permitted frequency band, and the needed accuracy is discussed. Furthermore, a novel method is raised to increase the temperature range under the same conditions. This work is supported by Natural Science Foundation of China under Grant No. 11174205.