Application of metamaterial-inspired resonators in compact microwave displacement sensors

There is an emerging interest in the application of metamaterial-inspired resonators for the realization of smart sensors. This paper briefly describes two main categories of metamaterial-inspired displacement sensors, namely, the displacement sensors based on shift in the resonance frequency, and sensors based on changes in the depth of resonance. The paper also highlights the advantages and disadvantages of each category in terms of dynamic range, sensitivity, compactness, and robustness to noise and changes in ambient conditions.