Min Zhang

Solving EMI problems isn’t only about ensuring that a product can meet EMC regulations and standards (although it’s a significant part of the job). Another crucial reason for addressing EMI issues is to enhance product reliability, especially when a product operates in public or industrial areas where there are many different types of noise sources.

Conducted emission tests can provide reasonably accurate results and also serve as a reliable indicator of radiated emissions, as some of these emissions propagate through cable wiring.

This article offers some useful insights and guidelines on how to effectively design and test systems using wide band gap devices to optimize product performance and achieve EMC compliance.

During conducted emission tests, one of the challenges manufacturers face is the resonance peaks in the harmonic noise somewhere between 10 MHz and 30 MHz. Often, no amount of filtering will eradicate or attenuate the peak.

When it comes to in-situ radiated emission measurements, the combination of near- and far-field measurements is often the best approach.

In this column, we discuss several important features of a spectrum analyzer not covered in previous articles that are worth your consideration.

Many individual components in electrical and electronic systems and devices are integrated into systems that are required to function as a whole. Examples of such systems include large electric vehicles, fixed industrial installations, novel scientific products such as quantum computers, and more. There are two EMC-related aspects to consider: intra-system EMC and inter-system EMC. This article focuses on the intra-system EMC aspect while also considering the inter-system aspect.

Although most modern RF amplifiers have a high voltage device rating against impedance mismatch, special care is needed to prevent impedance mismatch. To avoid impedance mismatch of the power amplifier, often an attenuator is also recommended to be connected between the output of the power amplifier and the flying probe.

Most EMI issues are caused by a resonance that is excited somewhere in the system. It may be a resonance of a cable acting as an antenna or a heatsink energized by the power electronics switches bolted to it, becoming a good radiator. In this article, we look at the indicators that signal the presence of structural resonances and provide techniques for fixing the EMI issues. Practical case studies are presented to demonstrate the techniques.

An AM radio can be useful for finding both radiated emissions and ESD events. Understanding how radio works is essential for engineers to use this low-cost technology to troubleshoot complex EMI issues.