Two-dimensional displacement and alignment sensor based on reflection coefficients of open microstrip lines loaded with split ring resonators

A two-dimensional displacement and alignment sensor is proposed based on two open-ended transmission lines, each loaded with a split ring resonator (SRR). In this arrangement, the depth of resonance-induced notches in the reflection coefficients can be used to sense a displacement of the loading SRRs in two orthogonal directions. Since the operation principle of the sensor is based on the symmetry properties of SRR-loaded transmission lines, the proposed sensor benefits from immunity to variations in ambient conditions. More importantly, it is shown that in contrast to previously published metamaterial-inspired two-dimensional displacement and alignment sensors, the proposed sensor can be operated at a single fixed frequency. The concept and simulation results are validated through measurement.