Investigation of Noise Reduction and SNR Enhancement in Search Coil Magnetometers at Low Frequencies

TL;DR

This paper presents a generalized model for search coil magnetometers, analyzing how coil and core dimensions influence thermal noise and SNR, with theoretical and experimental validation for low-frequency magnetic field detection.

Contribution

It introduces a more generalized induction coil sensor model and identifies optimal coil-to-core weight ratio and core aspect ratio for noise reduction and SNR enhancement.

Findings

Thermal noise magnetic field minimized by coil to core weight ratio.

Optimal core aspect ratio maximizes SNR.

Theoretical calculations agree with experimental data.

Abstract

Here, a generalized induction coil sensor model, more generalized than other models, has been considered and the equivalent magnetic field of the coil thermal noise and the sensor signal to noise ratio are calculated theoretically based on the dimensions and geometry of the coil winding and its core. Our calculations indicate that the equivalent magnetic field of the thermal noise can be minimized by the coil to core weight ratio. Moreover, it is found that the sensor signal to noise ratio can be maximized with only a special value of core aspect ratio length to diameter of core ratio. The calculation results here exhibit good agreement with the experimentally measured noise data.