"onyx" wrote in message
. ..
I think Richard..........."Ansoft's" HFSS".
Allow me post a couple of formulae ?? formulas ??
How about equations?

Balanis 2 Ed. p 32-33
Reactive near field - .62 * A
where A = Square Root of (D^3)/lambda
D= length of a Hertzian dipole (both elements)
lambda is the wavelength of a transmitting frequency
radiating near field - 2*(D^2)/lambda
Outside of that is the far field.
This is area that you seem concerned about.
Krauss uses Reactive near field as inside lamda/(2 * pie)

Do you work for a group of physicists? I have encountered the
field equations from a physics text by Young and Friedman.


Dave

Hi Dave:

By inspection, both of your equations show that the units of the solution
will be in meters. E field strength units are in V/m, and in the near
field, will be complex numbers. From memory, I believe your expression for
the near field/far field transition is correct. I do not have my own copy
of Balanis, but will check it when I get a chance.

Even for a non-realizable "Hertzian dipole", where the current is assumed to
be constant along its entire length, the math is fairly involved. Not sure
if a physics text is the best source for antenna studies. By what I have
read; Young and Friedman's texts have not had very good reviews -- by
students anyway!

No, I do not work for physicists. Most of the time I have worked in EE
labs. Electromagnetics is more of a hobby for me. So far I have been using
undergraduate texts, such as Paul and Nasar's "Introduction to
Electromagnetic fields". The problem with this book is that there are no
answers in the back.

Frank