Simulation Analysis on Characteristics of a Planar Capacitive Sensor for Large Scale Measurement

Measuring multi-dimensional linear displacements in large scale range with high precision is always focused on by researchers. This paper presents the results of simulation analysis on characteristics of a planar capacitive sensor (PCS), which is proposed for X and Y direction linear displacement measurement by measuring the periodic change of capacitance between two periodic plates, one fixed (i.e. fixed plate) and the other movable (i.e. movable plate). Since the capacitive electrode array on the fixed plate is periodically positioned, large scale measurement is realizable as long as the electrode array is large enough. The use of two geometrical orthogonal (90-degree out-of-phase) electrode arrays on the movable plate promises either axial displacement can be measured simultaneously without the coupling of another axial movement. The result of simulation proves 2-dimensional large scale measurement is feasible, meanwhile, different strategies are presented to fulfill structural optimization, including sensitivity optimization and linearity optimization.