Unique and unclonable capacitive sensors

Inspired from nature, a new concept called 'sensors with unique and unclonable characteristic', has been developed. Such sensors respond to a measurand and provide a unique output. Random variations in the structure of the sensors are responsible for these unique characteristic. It is very difficult to clone these sensors, since random variations are hard to measure, model, and duplicate. Such sensors are very interesting, as they can be used as a sensor with an integrated identifier. Details of unique and unclonable capacitive sensors are discussed in this paper. Each sensor consists of a PDMS membrane filled with randomly distributed conductive balls as functional element. When tilted, the functional element deflects and a planar electrode structure converts these deflections to change of capacitance values. Owing to the random ball distribution, characteristic of each sensor is unique and difficult to duplicate. The design, modeling, simulation, fabrication, and test of these capacitance-based, unique, and unclonable tilt sensors are presented.