Development Of Passive Wireless Temperature Sensor

Temperature is the most common and most commonly used variable in the process of production. In our daily life, temperature detection is crucial in the following filed:agricultural production, research and development of microelectronics technology, aerospace, high-speed rail transportation and so on. In recent years, the temperature sensing technology has experienced from wired to wireless, from active to passive. On the one hand, it related to the shortcomings of cable, active temperature sensing technology, namely, there exist a lot of problems, such as power supply replacement, maintenance costs, security, temperature limitations, large size, layout, etc. And passive wireless sensor technology can be applied in temperature measurement under the condition of bad environment, it can not only meet the needs of some strict conditions, but also has many incomparable advantages, especially in some special environment, such as rotating parts, sealing parts, high temperature, high corrosion environment. On the other hand, with the development of China’s Internet, intelligent technology, as an important technology in the branch of Internet of things, passive wireless temperature sensor has the following characteristics:low power consumption, safety, unattended, flexibility in aspects of network layout. These resulted in that it meets the demands of the development of the Internet of things. Therefore, passive wireless temperature sensor is the inevitable developing trend of temperature sensing technology in the future.This paper’s topic is selected from the institute of microelectronics, Chinese academy of sciences. This project is aiming at the condition that high temperature and high corrosive environment temperature is hard to be measured, the equipment and technology of process of research is provided by the microelectronics and semiconductor of Chinese academy of sciences institute.Through the analysis of the principle and manufacturing process of the temperature of the microstrip bandpass filter, the principle of schottky diode production, the method of wireless extraction, etc., we carry out a kind of passive wireless temperature sensor based on the principle of RFID. The temperature sensor has certain novelty. It is different from the other sensors, we detect the center frequency of microstrip filter’s reflected signal in the frequency domain and make a comparison between center frequency from above and the measured relational tables of center frequency and temperature, so as to realize the temperature measurement of harsh environments.Firstly, we designed the overall structure of passive wireless temperature sensor in this paper; Secondly, we focused on the design, manufacture and debugging of the hardware module (narrow band bandpass filter, Schottky diode, transceiver antenna). In the end, we assembled all the modules and tested it, through the test results we can see that the passive wireless temperature sensor has good performance in the range of 0-250,in addition, the structure is reasonable, the cost is low, so that it is convenient for mass production.