Fast Multi-Polarized Magnetic Field Measurements in the Frequency Range Between 150kHz - 30MHz

Low-frequency magnetic field measurements between 150 kHz and 30 MHz are traditionally done in the frequency domain. While these measurements are highly accurate, evaluating an Equipment Under Test (EUT) can take several hours or even days. To reduce measurement time, standards like CISPR-36 limit the number of measurement positions around the EUT, the measurement modes of the EUT, and the number of antennas used during the measurement procedure. These restrictions can lead to underestimating the highest emission levels around the EUT. This paper examines crucial aspects of current low-frequency magnetic field measurements below 30 MHz, highlighting areas for improvement and offering nowadays approaches to overcome limitations. These approaches include using novel multi-axis shielded loop antennas and a multi-channel receiver with time-domain measurement techniques. These proposed improvements can not only reduce the measurement time from several hours to mere seconds but also satisfy the accuracy required by the standards.