On Sun, 11 Mar 2012 20:40:54 -0700 Aaditya Kandibanda <aaditya.kandibanda@xxxxxxxxx> wrote: > Hello Mr Ritchey, > If I have a trace which is stitched to ground at both ends along > side of a another trace, will there be any current loop formed > which creates a EM radiation between the two traces? what path > will return current take? I have the same question. For instance, one design uses a two-layer PCB with an 18 MHz SPI bus between two ICs... there is no ground/power plane. I tried to heavily grid the power and ground on the board. A multi-layer board would be great, but many consumer products and high-volume low-cost sensor network devices can't bear the extra cost. In the first prototype of this board (yet to be tested), I put ground traces on both sides of the SPI signals because I was led to understand this will provide the lowest-impedance path for return current and thus the smallest possible current loop, since there is no real ground plane. If seems at first that an SPI bus (not terminated at either end, so near zero current into receiver) would exhibit more capacitive coupling effects than inductive since the current flow is minimal, but voltage swings on the signal lines are significant. (Capacitive coupling being generally based on dv/dt and inductive being based on di/dt?) Regards, Colin ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List forum is accessible at: http://tech.groups.yahoo.com/group/si-list List archives are viewable at: //www.freelists.org/archives/si-list Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu