Design and Fabrication of 3-D Printed RF Temperature Sensor Based on Microwave Coaxial Resonator

An RF temperature sensor based on a microwave coaxial resonator (MCR) is proposed. It introduced the physical process of thermal expansion to control the loading state of the metal induction plate (MIP) loaded at the port area of MCR through a metal thermal sensing linear expansion branch (MTSLEB) wrapped by a high-temperature resistant ceramic shell (HTRCS). The different loading states of MIP will make MCR acquire different additional capacitance. Therefore, the temperature information of the devices monitored can be obtained by extracting the resonance parameters of MCR in real-time. Since thermal expansion displacement of MTSLEB is adopted to control the resonance characteristics of MCR, the proposed sensor not only realized the separation of the temperature response region and the temperature information generation region but is also endowed with the features of simple structure, long service life, and adjustable temperature range and accuracy. With the broadband response characteristic of MCR (6.13 GHz) and the introduction of platinum (with a melting point of 1772 °C), the sensor is endowed with a theoretical temperature range of 1600 °C and average accuracy of 0.7% (3.83 MHz/°C). Based on 3-D printing, the proposed sensor is manufactured and measured, and the measurement results confirm its feasibility.