A Polarization-Insensitive, Metamaterial-based Sensor for Permittivity Measurement of Liquids

This paper proposes a reflective polarization-insensitive metamaterial-based sensor, comprising of an astroid-shaped resonance structure and a metal reflector, which can be used to detect the permittivity of liquid analytes. The resonance frequency of common edible oils such as canola oil, sunflower oil and olive oil are measured by the proposed sensor. In experiment, the resonance frequency are 128.3 GHz, 129.15 GHz and 130.5 GHz respectively, and their refractive indices being 1.54, 1.53, and 1.51, respectively. The sensitivity of the sensor is determined to be about 72.5 GHz/RIU, which makes it well-suited for the detection of analytes.