**From:** Doug McKean (*dmckean@corp.auspex.com*)

**Date:** Tue May 29 2001 - 13:58:21 PDT

**Next message:**Doug McKean: "Re: [SI-LIST] : RMS Definition"**Previous message:**Ingraham, Andrew: "RE: [SI-LIST] : Antenna Problem on the Board"**In reply to:**Chris Rokusek: "RE: [SI-LIST] : Antenna Problem on the Board"**Next in thread:**Chris Rokusek: "RE: [SI-LIST] : Antenna Problem on the Board"**Reply:**Chris Rokusek: "RE: [SI-LIST] : Antenna Problem on the Board"

Chris,

This E(f) relation being used looks like the magnetic

dipole equation. My question is in terms of radiation,

why is the magnetic dipole equation being used and

any more valid than the electric dipole equation?

Now, I understand the loop circuitry of a trace over a

ground plane, but traces can also act very much like

dipoles. Especially folded dipoles in some cases.

Where you have

H(f) = k(H) * [ I * f^2 * A / d ] (Amps/meter)

where

k(H) = 1.316*10^-14

I = amps

f = frequency in Hertz

A = area in meters squared

d = distance from antenna in meters.

You also have for the electric field

E(f) = k(E) * [ I*f*l/d ] (Volts/meter)

k(H) = 6.3*10^-6

I = amps

f = frequency in Hertz

A = area in sq. meters

d = distance from antenna in meters.

Two points:

One - I've seen this loop equation used quite a lot and

I have to disagree with it. There has to be some sine

or cosine factor in there as well as to compensate for

position from the loop.

Second, even if the magnetic relation is accepted, the

constant factors alone show that there are orders of

magnitude differences in amplitude between the two.

My bottom line here is that where people seem to

assume a loop, I see quite clearly a folded dipole.

- Doug McKean

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**Next message:**Doug McKean: "Re: [SI-LIST] : RMS Definition"**Previous message:**Ingraham, Andrew: "RE: [SI-LIST] : Antenna Problem on the Board"**In reply to:**Chris Rokusek: "RE: [SI-LIST] : Antenna Problem on the Board"**Next in thread:**Chris Rokusek: "RE: [SI-LIST] : Antenna Problem on the Board"**Reply:**Chris Rokusek: "RE: [SI-LIST] : Antenna Problem on the Board"

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