Detection Modalities of Displacement Sensors Based on Split Ring Resonators: Pros and Cons

The aim of this paper is to review various detection modalities of displacement sensors based on metamaterial-inspired resonators. With this aim, linear and angular displacement sensors based on split ring resonators are divided in two main categories: 1) Sensors based on the shift in the resonance frequency, and 2) sensors based on the symmetry properties of resonators. The second category can be divided in two subcategories: Type 1: sensors based on depth of notch, and Type 2: sensors based on frequency splitting. Principle of operation and examples of each sensing method are presented, and finally pros and cons of each method are summarized.