A compact miniature sensor based on a microstrip taper coupled to a metamaterial resonator

A Quasi-Lumped resonator fed through a tapered microstrip line is designed and implemented as a near field sensor for measuring the relative dielectric permittivity of low-loss unknown materials. The sensing principle is based on the shift of the resonance frequency as a function of the relative permittivity of the sample. In distinction with a related device we introduced lately, the proposed structure presents a compact geometry and it provides a higher sensitivity. Examples of operation of the sensor with four dielectric samples are presented and compared with state-of-art sensors.