In this paper we investigate an eddy current microsensor which uses a trans-impedance to minimize the influence of stray capacitances on its operation when being used for micromachine applications. The effect of stray capacitances can be minimized when using this type of amplifier by ensuring its input impedance is small. A technique for realizing very low input impedance over a wide bandwidth in these amplifier is studied. In additional new improved circuit configuration which further reduces the amplifier input impedance over a wider range of frequencies is investigated by computer simulation. Finally the experimental investigation of target materials suitable for achieving high sensor sensitivity is discussed.
Pei Lin Yu,
Ronald B. Zmood,
"Eddy current microsensor for use in micromachine applications", Proc. SPIE 3242, Smart Electronics and MEMS, (14 November 1997); doi: 10.1117/12.293551; https://doi.org/10.1117/12.293551