Frequency-Selective Surface to Determine Permittivity of Industrial Oil and Effect of Nanoparticle Addition in X-Band

A frequency-selective surface (FSS) structure is proposed for characterization of the permittivity of industrial oil using a transmission/reflection (TR) measurement scheme␣in the X-band. Moreover, a parameter study is presented to distinguish the dielectric constant and loss characteristics of test materials. To model the loss empirically, we used CuO nanoparticles artificially mixed with an industrial oil. In this study, the resonant frequency of the FSS is the basic parameter used to determine the material characteristics, including resonance properties such as the magnitude of transmission ( S 21 ), bandwidth, and frequency shift. The results reveal that the proposed FSS structure and setup can act well as a sensor for characterization of the dielectric properties of industrial oil.