Capacitive position sensor with simultaneous, linear X-Y readout

A design is presented for a compact capacitive position sensor suitable for operation at cryogenic temperatures and high magnetic fields. The four quadrants of a base electrode are excited with phases differing by 90 degrees; from its in- and out-of-phase components, the current injected into the movable electrode yields simultaneous information about the x and y sensor positions. This current is also linear in the position of the sensor. The effects of possible sensor imperfections are analyzed in detail. (C) 2000 American Institute of Physics. [S0034-6748(00)05506-4].