Planar sensors for RFID wireless complex-dielectric-permittivity sensing of liquids

Abstract

Two planar sensors for wireless RFID dielectric permittivity sensing of liquids are presented. The first sensor consists of a Substrate-Integrated-Waveguide (SIW) resonant cavity while the second one is composed by an SIW Epsilon-Near-Zero (ENZ) tunnel sensor. Both structures produce a notch resonance response at 4 GHz which is used for the characterization of the liquids using the Cavity-Perturbation-Technique. The proposed sensors present good sensitivity using a small amount of sample volume.