In message <001c01c6b604$c0ed2810$6401a8c0@homepc>, dated Wed, 2 Aug 2006, Iain Summers <[email protected]> writes >There are various references and opinions as to what constitutes the >near field far field boundary. The common one from antenna theory is >2D^2/lambda where D is defined as the largest aperture of the antenna.
There isn't a sharp boundary. What you take as the boundary depends on why you want to know where it is, and you don't tell us that. For example, you might decide that you want to know where the phase angle between E and H is only 1 degree. Or is 45 degrees. Or more. > >Has anyone researched what the limitations of this formula are? I am >interested in the far field boundary between 1-30MHz for large loops of >wire. Large compared with the wavelength at 1 MHz? That's large indeed! >In terms of a loop if this formula is applicable is D the circumference >or diameter of the loop. Or maybe the area? -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk 2006 is YMMVI- Your mileage may vary immensely. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________
