Electronic interface for position sensing using resonant cavities

The performance and accuracy of micro- and nano-positioning systems are directly linked to the measurement device used to close the associated control loop. In this work we propose, design, and test an electronic interface for a new position and displacement transducer based on resonant cavities. This type of transducer has been proven to achieve resolutions in the nanometer range when the detection is performed using a laboratory network analyzer. The proposed electronic interface is intended to provide a more affordable and compact solution, while preserving as much as possible the excellent performance of the transducer, thus, turning it into a true standalone positioning sensor. The operation of the interface establishes a self-resonance in the cavities and detects the resonance frequency (which is directly related to the position to be measured) by analyzing the attenuation produced by a low pass filter. The results obtained in a prototype of the interface built with discrete elements show that the obtainable positioning accuracy using this cost-effective solution is about 5 micrometers.