Design of a fast, high-resolution sensor evaluation platform applied to a capacitive position sensor for a micromirror

We present the design and implementation of an adaptable FPGA-based sensor evaluation platform. This platform is developed for benchmarking of an inkjet-printed capacitive position sensor for a resonant micromirror system as part of a smart packaging solution. In the target system, very high required resolutions of resolutions of res
_pos
<; 50 nm 50 nm together with a wide measurement range of r
_m
= 1000 pm at an offset of d
₀
= 1000 pm motivate the development of such a platform. Still, it is fully adaptable to other sensing principles (e.g. inductive). The suggested platform provides for high sampling rates (up to ≈ 10 ns) and enables generation of trigger signals, i.e. the mirror control signal, without time lag (as could result from high order filters). The online configurable FPGA block structure in combination with host software blocks enables flexible and individual design. The sensor read-out circuitry is designed as carrier frequency system. Such a carrier frequency system enables flexible choices of bandwidth and measurement signal frequency. It thus allows for separation in frequency from coupling parasitics, i.e. other frequencies present in the device under test (e.g. actuation frequency in case of the micromirror system).