At 11:18 AM 6/17/99 +1000, you wrote: > >Greetings and Salutations! I was wondering if this could be mailed out via >the epc-pstc channels. > >I want to know if anyone is doing any work in "near/ far field correlation >to commercial EMC standard limits" area and possibly correspond with them >with a view to exchanging notes.
Hi Arun, At a former company I spent a very large amount of time trying to correlate near field probe measurements of the surface currents and voltages of a product to far field (10 meter) measurements. In brief - it didn't happen. Even now, correlation between 3 meters and 10 meters is not guaranteed. And further, 3 meter to 10 meter correlation is at least "better" (define better anyway you wish) in the horizontal. Vertically it's terrible (define terrible anyway you wish). At least in my experience. And a product could be analyzed as being constructed of a variety of antennas - slots, corner reflectors, tuned cavity, tuned arrays, and either electric or magnetic dipoles ... each reacting it's own way in the far field. Now I'm not going to say it's impossible, but it seems to me that one must assume something to begin with instead of being able to blindly take a surface current measurement or near field measurement of X and state confidently that it WILL be Y in the far field under all circumstances. That's ultimately what one would have to be able to do without regard to the product. After a few rounds with a particular product, I've done this. I'm sure everyone at some point has done this. But with NO prior history of the product, I don't see how it's done. Regards, Doug McKean --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to [email protected] with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to [email protected], [email protected], [email protected], or [email protected] (the list administrators).
