Many electromagnetic interference (EMI) problems on PCBs happen when antennas are unintentionally created on the board.\u00a0 How can this be avoided?\u00a0 By making sure currents, especially high-frequency currents, travel in a loop.\u00a0 On high-speed lines, that loop is made up of a PCB trace AND the reference plane below it.\u00a0 Put a break in either one, and you’ve created an antenna.\u00a0 Obviously you would never consider breaking a signal trace, so why have a break in its reference plane?<\/p>\n
I discuss this in greater detail in a recent article in Printed Circuit Design and Fabrication Magazine:\u00a0 http:\/\/pcdandf.com\/cms\/component\/content\/article\/246-2012-articles\/9315-pcb-design<\/a><\/p>\n Avoiding such cases on very complicated designs with low layer counts\u00a0requires some planning early in the design cycle.\u00a0 Different busses should have their layers pre-determined and should be routed adjacent to ground and\/or their associated voltage planes.\u00a0 Otherwise, a trace could get routed across a plane split, which is a break in the reference plane that can cause EMI issues.\u00a0 Even with careful planning, signals may still end up getting routed across splits.\u00a0 Or, large gaps in the reference plane may get created from neighboring antipads or other similar structures.\u00a0 These issues can quickly and easily be pinpointed with an electrical rule checker like HyperLynx DRC (http:\/\/www.mentor.com\/products\/pcb-system-design\/circuit-simulation\/hyperlynx-drc-emi-emc<\/a>), and the issues resolved before the board gets fabricated.\u00a0 Trying to fix these kinds of issues on a fabricated board in the lab is next to impossible.<\/p>\n","protected":false},"excerpt":{"rendered":" Many electromagnetic interference (EMI) problems on PCBs happen when antennas are unintentionally created on the board.\u00a0 How can this be…<\/p>\n","protected":false},"author":71672,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"spanish_translation":"","french_translation":"","german_translation":"","italian_translation":"","polish_translation":"","japanese_translation":"","chinese_translation":"","footnotes":""},"categories":[13],"tags":[1029,1051,1052,1107],"industry":[],"product":[],"coauthors":[],"class_list":["post-752","post","type-post","status-publish","format-standard","hentry","category-news","tag-current-loop","tag-emc","tag-emi","tag-return-current"],"_links":{"self":[{"href":"https:\/\/blogs.sw.siemens.com\/electronic-systems-design\/wp-json\/wp\/v2\/posts\/752","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.sw.siemens.com\/electronic-systems-design\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.sw.siemens.com\/electronic-systems-design\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.sw.siemens.com\/electronic-systems-design\/wp-json\/wp\/v2\/users\/71672"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.sw.siemens.com\/electronic-systems-design\/wp-json\/wp\/v2\/comments?post=752"}],"version-history":[{"count":1,"href":"https:\/\/blogs.sw.siemens.com\/electronic-systems-design\/wp-json\/wp\/v2\/posts\/752\/revisions"}],"predecessor-version":[{"id":10343,"href":"https:\/\/blogs.sw.siemens.com\/electronic-systems-design\/wp-json\/wp\/v2\/posts\/752\/revisions\/10343"}],"wp:attachment":[{"href":"https:\/\/blogs.sw.siemens.com\/electronic-systems-design\/wp-json\/wp\/v2\/media?parent=752"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.sw.siemens.com\/electronic-systems-design\/wp-json\/wp\/v2\/categories?post=752"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.sw.siemens.com\/electronic-systems-design\/wp-json\/wp\/v2\/tags?post=752"},{"taxonomy":"industry","embeddable":true,"href":"https:\/\/blogs.sw.siemens.com\/electronic-systems-design\/wp-json\/wp\/v2\/industry?post=752"},{"taxonomy":"product","embeddable":true,"href":"https:\/\/blogs.sw.siemens.com\/electronic-systems-design\/wp-json\/wp\/v2\/product?post=752"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/blogs.sw.siemens.com\/electronic-systems-design\/wp-json\/wp\/v2\/coauthors?post=752"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}