Follow these 18 rules for better EMC design

The measures described in this article can go a long way to reduce radiated emissions due to return voltages. For most devices, return voltages are the dominant cause of radiation for frequencies up to several hundred MHz. Upward of that, loops of current on the printed circuit boards themselves can act as radiators to a significant degree. Nonetheless, the same techniques employed here to reduce radiation will work to reduce radiation directly from these loops as well