View Single Post
  #9   Report Post  
Old December 15th 06, 05:04 AM posted to rec.radio.amateur.antenna
art art is offline
external usenet poster
 
First recorded activity by RadioBanter: Sep 2006
Posts: 1,188
Default A request for guidance from academics


Dave wrote:
"art" wrote in message
ups.com...
I recently gave a write up on Gaussian arrays
As a sample which was not directed for any
desirable I laid out the following

All of the elements were placed above each other purely
to make things easier to do plus it being an unusual
arrangement probably never seen before.

Coordinates ( perfect ground) Inches
X Y Z

0 209.46 927.1
0 198.25 973.97
0 172.78 822.86
0 219.83 964.4
0 185.53 922.4

With 1" dia elements
my results were
Impedance 48.5 + j 0.1
Horiz gain 8.12 dbi @ 12 deg
Rc gain 5.11 dbic

Since I am not sure of the capabilities of EZNEC
or other programs
I also supply the following

All elements driven impedances are
6.58 + j56.9
-5.28 - j 37.6
-5.00 -125
9.35 + 58.5
-16.2 - j205


as i pointed out before, and this verifies, you have found one of the
limitations of finite element methods for modeling antennas. very close
spacings between long elements causes un-realizable results. the extremely
low real components of the impedance and high reactive values are symptoms
of this.


Now I need the help from anybody with a engineering degree
which wipes out Richard since his only intent is to ridicule,
or deceive anyway, to confirm the following

For a Gaussian field the energy radiated
by the array as a whole ( feed element 1 )
must equal the sum of the energy
supplied from each individual element.


this is true for any array.


Questions.
1. Am I correct in saying this?
2. Does the above array rank in any way
as a Gaussian array.?


define 'gaussian array' as it applies to antennas that you are describing.

that type of array is not defined in my copies of Jackson's or
Ramo-Whinner-VanDuzer's books,

+++++++++++++++++++++++++++++++++++++++++++++++++

David,
since you referenced the above book may I bring to your attention
to Potentials used with varying charges and currents with the sub
heading
A "possible" my quotes set of potentials for time -varying field
paying attention to the significance of "possible" Deeper in the
chaptor he refers to static fields.
I know his use of the word 'possible' does not endorse anything but he
didn't rule it out

In addition page 70 refers in depth with respect to Gauss's law where
he supplies a drawing of a partial surface of a volume ( arbitary
surrounding surface is the statement ) where the charge is a projection
on the surface without reference to what it is projected from. In my
case it is a projection from a cluster of elements) definitions and
concepts, without any furtherexperimental information
He also goes on to state Gauss law in his own words and then goes on to
say
It has been derived from Coulombs force by the introduction of new
definitions and concepts I am just adding to the concept by adding a
third dimension which when looking at the drawing given reflects the
original Gaussian thinking tho current thinking uses a two dimension
section in describing electrostatics.I suppose a good proof would be to
compare Pointings vector formulae with what I have put forward but
perhaps that is too presumtious of me.
All in all the array represents a band pass filter where effort is made
for constant gain across a band of frequencies which is a different
requirement from the Yagi where amateurs
are only interested in gain without due referance to constancy across
the frequency span
or with regard to the corresponding beam width
Any way the above should provide some food for thought
Bed time calls

Best regards
Art Unwin



nor does my IEEE antenna design handbook
mention that term. there are references to 'gaussian beams' with respect to
the shape of the fields from feed horns for microwave dishes and other
quasi-optical systems. Some searching of the web also seems to refer to
gaussian arrays, but those all seem to be related to current or power
distribution on elements of an adaptive array.



Frankly, one or more of you is an academic so I really am
pointing at you for direction so I can be sure that my
program has not somehow become corrupted
I am sharing this with you so can you share
your input with me? If you prefer to communicate
by E mail with me that is fine since we know that
the lips of some will spew
Art