Microwave biosensor based on a double metamaterial particle

In this paper, a theoretical study of biosensor based on microwave split-ring resonators (SRRs) excited by microstrip transmission line is presented. The sensor consists of a microstrip line loaded with circular SRRs on both sides. The proposed metamaterial sensor was designed on Rogers RT5880 substrate having dielectric constant of 2.2 and thickness of 0.76 mm. The operating principle of these biosensor is based on the interaction of the electromagnetic near-field generated by the sensor with the samples under investigation. The SRR can be considered as an LC resonator circuit whose frequency response is very sensitive to the changes in capacitive and inductive effects. At the resonance frequency, the resonator develops an intense and localized electric across the split, enabling sensitive detection of extremely small amounts of simples. The detection method is based on the principle of the shift of the resonance frequency as a function of the relative permittivity of the loading sample. In order to enhance sensing performance of the device, a new split gap are adding in each rings, that will provide a strong and localized field enhancement in the selected area, increasing the high electric field region. The shift of the resonance frequency in the presence of a sample material is characterized by multiple resonant frequencies, upon introduction of several samples with different dielectric value. The metamaterial resonator is tested through proper full-wave numerical simulation (HFSS) based on the finite element method (FEM).