Research On The Calibration Methods Of LF Exposure Level Tester With Reference Field

With the continuous development of science and technology, the more widespread usedof electronic equipment. At the same time, there is a growing emphasis on electromagneticexposure of the health of the person, the low-frequency magnetic field exposure meter use ofmore and more widely applied in environmental protection, product authentication andelectromagnetic compatibility(EMC). Accuracy of this type of instruments, affect the result ofthe measurement, and the affect to make judgments. Measuring instruments need to becalibrated on a regular basis in accordance with our traceability system. Currently, there is nonational metrological verification and calibration specifications of low-frequency magneticfield exposure meter no national metrological verification and calibration specifications, andthe calibration method is immature. Channels of such instrument is not traceable, can notguarantee the reliability of the instrument measurement values. Therefore, it is very importantto research low-frequency magnetic field exposure meter calibration method, and create alow-frequency magnetic field exposure meter calibration system to solve this kind ofinstrument traceability.The paper mainly the following aspects of the research from the metering point, effortsto solve the following aspects:(1) The calculation of the standards field of transverseelectromagnetic cell and establish calibration system;(2) The research of standard fieldgenerated by the Helmholtz coils and establish calibration system;(3) The research ofstandard field generated by the double-square coil and establish calibration system.The papers focus on the principle of a coil generating a magnetic field. There are threemethods, one using a Helmholtz coil, suitable for the probe is small, and the high frequencysituation, the other is using a square coil, the benefits of this coil is easy to manufacture, canbe made very large and uniform, suitable for high-precision measurement, but only forfrequencies near the labor frequency. Analysis the standard field generated by the TEM cell(transverse electromagnetic cell). Third，The magnetic field generated by the TEM cell isrelatively small, suitable for a small range; due to the influence of the volume of, TEM cellgenerating the magnetic field suitable for a small probe, uncertainty slightly larger. The paperuses spreadsheet Excel software writing formulas to facilitate the calculation of the magneticfield strength and uniformity of the double square coil and the Helmholtz coils. Makingrelatively difficult uniformly analysis becomes easy.The innovation of the paper is that the difficult problem of low-frequency magnetic field exposure meter calibration, integrated use of derivation, preparation of formulas, experimentsand other methods to analyze the principle of generating a magnetic field and uniform area ofthe Helmholtz coils, double square coil and the TEM cell mechanism, put forward a setofbased calibration standard field programs, proposed a calibration method based on standardfield. Establish a system of low-frequency magnetic field exposure meter calibration,measurement uncertainty analysis.Experiments show that, Based on on standard field method using a Helmholtz coil, thethe double square coil and the TEM cell to establish the low-frequency magnetic fieldexposure meter calibration system with high accuracy to meet the requirements oflow-frequency magnetic field exposure meter calibration. To solve the traceability problem oflow-frequency magnetic field exposure meter．...