Need Help about 3W spacing rule

[JackSanji]

Hi all,
Can anyone tell me why routing using 3-W rule ( 3 width rule ) can help reduce 70% magnetic field, and 10-W help to reduce 98% magnetic field of each other trace?
Any official document for that rule or it's just the experiment?
Thanks!

 

[marce]

You jest?
We are referring to the magnetic field around any conductor, any official document for that rule!!!!!... Start with Maxwell
http://en.wikipedia.org/wiki/James_Clerk_Maxwell
Some other stuff with pretty pictures
http://www.qsl.net/va3iul/Microstrip_Stripline_CPW_Design/Microstrip_Stripline_and_CPW_Design.pdf
http://blog.lamsimenterprises.com/category/signal-integrity/useful-equations/
http://www.pcbdesign007.com/pages/columns.cgi?clmid=65&artid=76292&_pf_=1
http://www.pcbcarolina.com/images/sscearce-xtalk-ipc.pdf