A non-contact passive electromagnetic transmitter to any capacitive sensor- design, theory, and model tests

This paper presents a non-contact passive electromagnetic interface especia lly dedicated to capacitive sensors. Ln contrast to radio transmitters coop erating with remote sensors, our interface is extremely simple and requires integration only for the single plane coil with the capacitive semiconduct or sensor structure. The interface structure and theoretical calculations d one with the use of the Grover method are discussed in the paper. Presented data from interface tests proved that the interface can successfully opera te with the frequency of some 11 MHz obtaining sensitivity of some 15 Omega /pF in the range of 0-22 pF. (C) 2000 Elsevier Science S.A. All rights rese rved.