In the paper we can get explanation such as current density, eddy current sensors, range, sensor, position sensors, oscillator, nominal working frequency, optimal performances, impedance, range sensor, piezoelectric actuators, and variation. The paper gives the reader info about frequency response, voltage output, current, circuit, design, configuration, actuators, performances, voltage, sensitivity, and eddy current.
Many things regarding modelling, thermal drift, density, the eddy current, piezoelectric, force sensor, current sensors, measurement, printed circuit board, manufacturing, resolution linearity, and the resonant frequency are explained inside this paper. Below are some excerpt from the paper:
The scaling down process can be done until parasite effects modify the performance sof the sensor: a 1500µm range sensor in a 5.8mmx5.8mm*1.8mm volume has been designed and tested to validate the performance and a 500µm range sensor has been simulated to validate the intrinsic probe performance in small volume 2mmx2mmx1mm.  Target Material, “the good, the bad and the hugly”: website of Kaman Precision, www.kamansensors.com  Roach: Designing and Building an Eddy Current Position Sensor, Sensors Magazine, 1998  Welsby, Hitz: True Position Measurement with Eddy Current Technology, Sensors Magazine, 1997.
Giving more content, the paper presents more things like sensors, position sensor, the optimal performances, eddy currents, resolution, circuit board, manufacturing process, position sensing, electrical connections, working frequency, and linearity.