Tests of a novel 3 DOF differential capacitive sensor

A four-quadrants differential set-up made by two plane-parallel capacitors to measure displacements and small angle rotations is presented. The capacitors electrodes are interfaced to a bridge-based circuit of new conception to be used either for displacements and small angle readings, independently and almost simultaneously detected. Sensitivities of about $0,11\ \mathrm{V}/\mu \mathrm{m}$ with a 0,1% relative standard deviation, and of $0,13\ \mathrm{V}/\text{mrad}$ with a 0,3% relative standard deviation, were determined over displacements up to $\pm 50\ \mu \mathrm{m}$ and yaw rotations up to $\pm 10\ \mu \text{rad}$ .