Looking for Gold in EMC Emissions Test

摘要

The search for a practical reference in EMC emissions measurements may parallel Jason's quest for the golden fleece. Just like Jason, in attempting to realize a noble goal, we keep running into labyrinths of complexity and detail. With most measurements, you use an instrument calibrated by comparison to a standard or reference. But in EMC measurements, the seemingly simple task of achieving repeatable and reproducible results still forms the bulk of today's research. So what's the problem? Well, the reference for EMC emissions measurements isn't something you'll find on a laboratory shelf. It's the behavior of free space. That's the place where all waves are plane waves, the characteristic impedance is 377 Ω, and the E- and H-fields are in- versely proportional to the distance from the source.