Development of 'lick and stick' passive wireless temperature sensor for harsh environment

Wireless passive temperature sensors have been receiving increasing attention due to the ever-growing need of higher energy efficient and precise monitoring of temperatures in high temperature energy conversion systems such as gas turbines and coal-based power plants. Unfortunately, the harsh environment such as high temperature and corrosive atmosphere present in these systems has significantly limited the reliability and increased the cost of current solutions. Therefore, this research project presents the concept and design of a low cost, passive, and wireless temperature sensor that can withstand high temperature and harsh environment. The temperature sensor was designed following the principle of metamaterials by utilizing Closed Ring Resonators (CRR) in a dielectric matrix. The proposed wireless, passive temperature sensor behaves like an LC circuit, which has a temperature dependent resonance frequency. A full wave electromagnetic solver Ansys Ansoft HFSS was used to validate the model and to evaluate the effect of different geometry and combination of SRR structures on the resonance frequency and sensitivity of the proposed sensor. Two different fabrication methods - compression method using a die-punch assembly and 3D printing using binder-jetting techniques were used to fabricate the sensors. To simplify the sensor design, commercially available metal washers were used as CRR structures. Barium Titanate (BTO), and Alumina (Al2 O3) were used as dielectric materials. Material characterization was done using Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD), and preliminary free space testing at room temperature using horn antennas and Gaussian beam antennas very promising results for using this novel sensing system for harsh environment application.