Multi-functional metamaterial sensor based on a broad-side coupled SRR topology with a multi-layer substrate

This paper intends to demonstrate the feasibility of a miniaturized multi-purpose metamaterial sensor that can be effectively used for chemical, biological and pressure sensing in microwave and terahertz applications. This novel sensor design makes use of the double-sided split ring resonator (DSRR) topology that is modified to have an additional sensing medium sandwiched between two identical broadside coupled SRR unit cells. The resonance frequency of the resulting DSRR sensor shifts as the dielectric permittivity or thickness of this interlayer medium changes in response to variations in an environmental parameter such as temperature, humidity, density, concentration or pressure. As a proof of concept study, both numerical and experimental results are presented with very good agreement for a multi-functional miniaturized metamaterial sensor prototype operating in X-band. Simulations for three different real-life scenarios are also presented for this sensor topology to demonstrate a moisture sensor, a density sensor and a temperature sensor with very good sensitivities where the interlayer medium is occupied by sawdust, silica aerogel and seawater, respectively.