Probe influence on the measurement accuracy of nonuniform LF magnetic fields

The error introduced by the coil size averaging effect when measuring nonuniform low-frequency (LF) magnetic fields is investigated with particular reference to the use of field meters equipped with nonconcentric coil probes. The analysis is developed by computation and the results are validated by comparison with experimental data. The influence of different parameters, such as source type, distance of the probe from the source, coil dimension, and probe orientation, is investigated and quantified. The results are synthesized by introducing limit distances from the field source, beyond which the averaging error is lower than a stated value. An estimate of the uncertainty component due to averaging error is also given.