PT-Symmetric Inductive Displacement Sensors

We propose a new type of wireless displacement sensor based on the concept of parity-time (PT)-symmetry. The PT-symmetric wireless sensor consists of a -RLC tank (reader) and a RLC (tag) tank, which are inductively coupled to fulfill the PT-symmetry condition. Specifically, when this wireless sensor is operated nearby the exceptional point (EP), uniquely existing in the PT system, it can exhibit highly sensitive frequency responses with respect to the change in the distance between reader and tag. The effectiveness of the proposed wireless displacement sensor is experimentally verified, showing great potential for high-precision displacement, position and distance measurements, assessment of civil infrastructures, as well as industrial and medical internet-of-things (IoTs).