Conference Agenda

Radiated electromagnetic emissions requirements are defined as field strength levels that must not be exceeded when measured at a standard reference distance from the equipment under test. However, when such emissions are measured by placing the antenna at a distance different from the reference one, conversion factors are employed to adjust the emissions limits accordingly. This paper compares five alternative proposals of distance conversion factors for magnetic field emissions limits in the frequency range from 150 kHz to 30 MHz. This analysis intends to identify commonalities and differences between independent proposals presented in research articles, technical reports, and standards. The results suggest the different proposals could be merged into a single set of H-field conversion factors. Moreover, throughout the application of conversion factors in real cases, it is confirmed that, for in situ testing, H-field limits defined for distances greater than 10 m are likely to be surpassed by the ambient levels specially for frequencies higher than 4 MHz.

Several standards must be fulfilled before putting medical devices on the market. The use of harmonized standards provides a level of assurance that the equipment will not deteriorate the performance of radio services and other equipment in the intended use environment. The standards for medical equipment from the IEC 60601 series play a crucial role in this certification process. This contribution focuses on the radiated emissions conformity requirements from IEC 60601-1-2 and CISPR 11, which impose limits to electromagnetic disturbances radiated from medical devices. The current versions of the medical standards do not yet address test requirements for radiated emissions in the frequency range 1 – 6 GHz for Group 1 equipment. Since the release of CISPR 11 Edition 7.0 in 2024-02, new requirements for radiated emissions in this frequency range were introduced. A simple adoption of established measurement methods known from CISPR 32 and CISPR 16-2-3, cannot be performed because large medical products, such as angiographic X-ray systems, ME systems for nuclear medicine, CT systems, etc., have large dimensions. Therefore, regular fully-anechoic rooms or absorber-lined semianechoic chamber test setups require major modifications such as reducing the amount of used floor absorbers. We analyze the radiation behavior of different large ME equipment and propose an adapted test setup suitable for these products. As a result, practical guidance for performing radiated emissions tests on large ME equipment is provided.

A novel approach for a reference radiator for the frequency range from 1 GHz to 18 GHz is presented. This approach has several advantages compared to present implementations, like the higher and settable output level. The usage with spectrum analysers and EMI receivers is shown and the measurement time is calculated with 22.5 s, which is reasonable. A temperature compensation is implemented which improves the temperature stability by almost a factor of ten compared to step recovery diode based implementation. A prototype was built and tested to demonstrate that the approach can be implemented into reality. The downside is the much higher effort of manufacturing which drives up the cost for future commercial products.

This article quantifies an aspect that every EMC engineer is intuitively aware of: At low frequencies, as long as the boxes are electrically small, one can estimate the far field from the cable currents, but engineers may not know how to do this, and how good is that estimate? The paper compares different methods that can be used to estimate the radiated fields from the currents. The analysis is based on about 100 different geometries, cable and ground plane termination impedances. Full-wave simulation is used to calculate the currents and the far field, and estimation methods that use the cable current to obtain the far field are compared. It is shown that a combination of methods leads to average estimation errors of less than 4 dB for a frequency range of 30-500 MHz, with lower errors in the 30-300 MHz range.