Estimation of the Highest Influence on the Measured Results of a Three-axis Shielded Loop Antenna Using Three Transmitting Antenna and Tilted Antenna Methods

Low-frequency radiated EMI measurements around equipment under test are typically based on the measurement of the magnetic field components with a shielded loop antenna. The number of measurement positions, antenna orientations, and different types of detectors that vary from standard to standard have a great impact on the measurement time. Several possibilities to reduce measurement time, such as time-domain measurements, have been investigated with promising results. However, to decrease measurement time, even more, the opportunity to measure several antenna orientations simultaneously should be taken into account. Via multichannel measurement devices in combination with a three-axis shielded loop antenna, the magnetic field measurement time could be reduced even more. In this paper, the measurement error created by a three-axis antenna compared to a single shielded loop antenna is evaluated. Measurements of the influence of additional antennas in three-axis antenna construction were carried out by changing the orthogonal field components independently. Measurements are supported by simulations and show a clear overview of the usability of a three-axis shielded loop antenna.