Development of metamaterial based low cost passive wireless temperature sensor Hasanul Karim* 1 , Mohammad Arif Ishtiaq Shuvo 1 , Diego Delfin 1 , Yirong Lin 1 , Ahsan Choudhuri 1 , R. C. Rumpf 2 1 Department of Mechanical Engineering, The University of Texas at El Paso, TX-79968; 2 W. M. Keck Center for 3D Innovation, University of Texas at El Paso, El Paso, Texas 79968 ABSTRACT Wireless passive temperature sensors are gaining increasing attention due to the ever-growing need of precise monitoring of temperature 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 limits current solutions. In order to alleviate these issues, this paper presents the design, simulation, and manufacturing process 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) embedded in a dielectric matrix. The proposed wireless, passive temperature sensor behaves like an LC circuit that has a resonance frequency that depends on temperature. A full wave electromagnetic solver Ansys Ansoft HFSS was used to perform simulations to determine the optimum dimensions and geometry of the sensor unit. The sensor unit was prepared by conventional powder-binder compression method. Commercially available metal washers were used as CRR structures and Barium Titanate (BTO) was used as the dielectric materials. Response of the fabricated sensor at room temperature was analyzed using a pair of horn antenna connected with a network analyzer. Keywords: Wireless, temperature sensor, harsh environment, metamaterials, Closed Ring Resonator 1. INTRODUCTION Metamaterials are man-made materials that can show extraordinary properties that are not present in nature 1 . These materials are usually arranged periodically to duplicate the structure of an atom. Depending on the shape, size, orientation, and arrangement, metamaterials can show different exclusive properties such as negative refractive index 1 , cloaking 2 , and reverse Doppler effect 3 . Because of these unique properties, metamaterials have opened a new horizon of possibilities. The potential applications of metamaterials are remote sensing, remote aerospace applications, solar power improvement, communications, improving ultrasonic sensors and shielding structures etc. 4 . Wireless passive sensors are currently getting broader attention in the industry. These sensors are convenient as they are wireless and do not require any additional power supply. Optical based wireless sensors were developed but the accuracy of these sensors was not satisfactory 5 . SiC and Si 3 N 4 based micro-sensors have been introduced in harsh chemical environment at high temperature, but the complexity of the fabrication process makes it costly 6 . Metamaterials were introduced to remove these limitations. Arbabi et al. proposed a metamaterials based surface plasmon resonance sensor in Terahertz region 7 . Several approaches were made to develop wireless passive temperature sensors capable of sustaining high temperature and harsh environments. Among these approaches, Split Ring Resonators (SRRs) have gained significant attention and are the most common metamaterial reported to date. Ekmekci et al. demonstrated the feasibility of different types of SRR structures for different types of sensors 8 . They suggested broadside-coupled SRR structure for temperature, humidity and concentration sensor application. Scott and Peroulis presented a slot antenna with an embedded temperature sensor which can sense up to 300°C 9 . However, in energy system application, the temperature range can be much higher. Therefore, there is an increasing need in developing low cost wireless temperature sensor with enhanced operational temperature range. The objective of this paper is to propose a metamaterial based temperature sensor that can sense temperature up to 1000°C. This will be achieved by utilizing a dielectric matrix and a closed ring resonator (CRR). The ring resonator behaves like an LC oscillator, as shown in Figure 2 (b), where the metal ring acts as an inductor and the material in between the ring gap acts as a capacitor, detailed LC equivalent circuit calculation can be found elsewhere 10 . Therefore, the resonating frequency of the SRR can be determined as, Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2014, edited by Jerome P. Lynch, Kon-Well Wang, Hoon Sohn, Proc. of SPIE Vol. 9061, 90612K © 2014 SPIE · CCC code: 0277-786X/14/$18 · doi: 10.1117/12.2045242 Proc. of SPIE Vol. 9061 90612K-1 DownloadedFrom:http://proceedings.spiedigitallibrary.org/on05/13/2014TermsofUse:http://spiedl.org/terms