Passive wireless sensors fabricated by spark plasma sintering for ultra-high temperature measurements

Abstract

A passive and wireless sensor based on LC resonator for ultra-high temperature measurement was designed and fabricated. The sensor consisted of a molybdenum split-ring resonator (SRR) encapsulated by an alumina ceramic matrix. The alumina ceramic matrix served as not only a dielectric material for sensing the temperature variation, but also a protective material for the SRR. The SRR was made of molybdenum by chemical etching, while the alumina ceramic shield was fabricated by spark plasma sintering (SPS). Small amount of MgO was doped into alumina powder to assist the sintering of a fully dense ceramic, preventing the molybdenum ring from high-temperature oxidation. A high temperature measurement system was built to investigate the performance of the fabricated sensor. The temperature measurement ability of the sensor was verified up to 1200 °C, with high sensitivity and good temperature resolution.