Compact miniature sensors based on tapered lines coupled metamaterial resonators

This work presents two tapered transmission lines coupled quasi-lumped resonators as miniaturized sensors intended for liquid mixtures concentration measurement. The first resonator is designed in the parallel plate's topology, and the second one in the coplanar waveguide topology. The main part of the aforementioned resonator is an interdigital capacitor where the confinement of an intense electric field is ensured. The sensing principle is based on the shift of the resonance frequency according to the liquid fraction variation. Due to their small electric size, small sample volume and other advantages, also in comparison with other sensors based on the use of conventional SRRs, the proposed quasi-lumped resonators offer inexpensive compact structures. Examples of operation of the sensors with methanol/ethanol mixtures samples are presented to highlight the performance of the proposed resonators for near field sensing applications. Simulation results are exploited by using Ansoft High Frequency Software Simulator (HFSS).