A Wireless Temperature Sensor Applied to Monitor and Measure the High Temperature of Industrial Devices

In this article, a wireless temperature sensor based on a log-periodic dipole antenna (LPDA) and cavity filter, which can be applied to realize wireless monitoring and measuring the temperature of industrial devices, is proposed. By introducing the wide-band LPDA (4.5–10 GHz) into the input port and output port of the cavity filter with the status of orthogonality, respectively, the proposed sensor is endowed with the ability of wireless transceiver wide-band microwave signals with noninterference. Furthermore, to control the response characteristics of the proposed cavity filter by the monitoring temperatures, a coupling column is loaded by means of good contact and sliding up and down and connected by ceramic flange to a metal thermal sensing expansion branch (MTSEB) wrapped by a high temperature resistant ceramic shell (HTRCS). Then, by loading the corresponding LPDAs on the dual port of the vector network analyzer (VNA), extracting and analyzing the feedback signals from the sensor in real time, the temperature information of the industrial devices monitored will be obtained. Simulation and measurement results indicated that it has a reliable theoretical high-temperature wireless measurement capacity of 1400 °C with an average accuracy of 0.356 MHz/°C for industrial devices.