[Elecraft] EH Antenna Patent

Wed Feb 26 12:48:00 2003

Thanks for filling in the blanks, Earl. Glad to see that the Socratic
approach still works.

And just to fill in the blanks a bit more, the presence of both fields in
quadrature space relationship and in-phase time relationship and with a
magnitude ratio of 377 (ohms) constitutes radiation in the far field. The
cross-product of the two fields defines the Poynting vector which describes
the direction of the radiating wave as well as its magnitude.

Near-field conditions can be considerably different. There can be regions of
predominately E-field or H-field concentration but this does not constitute
"radiation" in the sense of far-field phenomena.

Interesting stuff . . . amazing that four little equations could say so
much.

73/72, George
Amateur Radio W5YR -  the Yellow Rose of Texas
Fairview, TX 30 mi NE of Dallas in Collin county EM13QE
"In the 57th year and it just keeps getting better!"

 -----Original Message-----
From: [email protected]
[mailto:[email protected]]On Behalf Of [email protected]
Sent: Wednesday, February 26, 2003 10:32 AM
To: [email protected]; [email protected]
Subject: RE: [Elecraft] EH Antenna Patent

George, W5YR wrote:

"What is "E-only" or "H-only" radiation?"
==========
The ARRL Antenna Book says:

"Although the solid pattern of an antenna cannot be shown adequately on a
flat sheet of paper, cross-sectional or plane diagrams are very useful.
Two such diagrams, one in the plane containing the axis of the antenna
and one in the plane perpendicular to the axis, can give a great deal of
information.  The former is called the E-plane pattern and the latter the
H-plane pattern.  These designations are used because they represent the
planes in which the electric (symbol E), and the magnetic (symbol H)
lines of force lie, respectively."
==========
All electromegnetic waves have both E-plane and H-plane components and,
as George pointed out, "You can't have one without the other".

73, de Earl, K6SE
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