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

Abstract

This paper presents a non-contact passive electromagnetic interface especially dedicated to capacitive sensors. In contrast to radio transmitters cooperating with remote sensors, our interface is extremely simple and requires integration only for the single plane coil with the capacitive semiconductor sensor structure. The interface structure and theoretical calculations done with the use of the Grover method are discussed in the paper. Presented data from interface tests proved that the interface can successfully operate with the frequency of some 11 MHz obtaining sensitivity of some 15 Ω/pF in the range of 0–22 pF.