A Noncontact Feed Microwave Temperature Sensor for Industry Device Based on Metamaterial

In this article, a noncontact feed temperature sensor consisting of a metamaterial array, a feed network, and a cavity filter was presented. Meanwhile, a waveguide antenna (WA) was introduced for wireless signal transceivers. Specifically, when the temperature changes, the tuning effect of the metal thermal sensing branch (MTSB) will cause the cavity filter systemically equivalent impedance to change through its thermal expansion displacement. Then, the signal reflection intensity of the metamaterial array will be changed accordingly. Therefore, the temperature information can be obtained by extracting the radiation information of the metamaterial array with WA. Therefore, by introducing the appropriate MTSB, it will be endowed with a theoretical ultrahigh temperature monitoring capability of more than 1100 °C. To verify the sensor’s feasibility and reliability, the brass thermal sensing branch (BTSB) and the ceramic shell (CS) were introduced. Through preparing and testing the proposed sensor, its feasibility and reliability were proved with the average temperature measurement resolution of 0.0097 dB/°C within the test temperature range of 752.2 °C. Considering the characteristics of compact structure and noncontact feed, it can be predicted that it will be of great value in status monitoring and health management of industrial devices.