On 30 May, 10:21, (Richard Harrison) wrote:
Art wrote:

"The three phases of radiation are the current application and the
electron emission, formation of the near field and finally formation of
the far field."

The questioner asked: "If I want to compute the voltage induced on the
antenna by the field, do I add the two E field components or do I
compute the norm of the vector on the RHS of eqn (II) ?"

Art replied:
"Gain can mean many things."

Terman defines on page 870 of his 1955 opus:
"The extent of such concentration relative to that of some standard
antenna, termed the directive gain, is defined quantitatively as the
ratio of power that must be radiated by the comparison antenna to
develop a particular field strength in the direction of maximum
radiation to the power that must be radiated by the directional antenna
system to obtain the same field strength in the same direction."

Kraus shows how to handle arrays of point sources. All the math is
included.

Kraus wrote on page 12 of the 3rd edition of "Antennas":
"Antennas convert electrons to photons or vice versa."

If the questioner draws his information from Terman and Kraus, he won`t
err.

Best regards, Richard Harrison, KB5WZI

Richard, you evoked the phrase Poyntings vector which is an excellent
point to start
with respect to the formation of radiation especially with respect to
mathematical analysis
I iknow that you mentioned a couple of books to add weight to your
response
but a circular polarised wave has no place what so ever in a
mathematical analysis
of Poyntings vector. Yes we all know that there is a 3db difference
when looking
at the gain of a circular polarised antenna as well as many other
facts with
respect to antennas but you invoked "poyntings vector" where flux
movement
is used as a mathematical beginning. I am not disputing anything that
is
in the books that you often refer to but only how you interprete the
written word
to add authority to your analysis where it has no place.
I say again, since you evoked the term Poyntings vector in response to
mathematical
question that is no place to insert polarisation differences that may
take place
not in the Poynting areana but at a much later stage in radiation.
However, since you muddled things up by introducing Pointings vector
and coupled it
to circular polarisation maybe you can enlarge how this vector changes
with respect
to the choice of polarisation. Don't waffle by reciting books and
facts written
in books that don't relate to the subject at hand but give an
explanation to
the poster who acknoweledges that he is new to antennas but not to the
mathematical
aspects of same.
He is asking for assistance and not a measure of your personal
knoweledge or the books that you have or what you believe the
intent of the author is in what he states.
Regards
Art