On Tue, 26 Aug 2008 12:18:37 -0700, John Smith
wrote:

This is a bit off topic in direct relation to your post; however, I
built this antenna as an external to my wifi router/switch to increase
coverage of the net:

http://www.centurion.com/home/pdf/wp_omni_wireless.pdf

Fig. 1-5 and the plot of the radiation pattern (fig. 1-7) I found
particularly interesting ...

Drifting further off topic.... Here's the commercial incantation of
that antenna (the three photos on the right) from Tecom:
http://802.11junk.com/jeffl/antennas/tecom/index.html
PCB losses make it a rather marginal performer.

Note the added decoupling sleeve. That somewhat beam uptilt due to
the effects of the mounting hardware.

The worst part of the design is that 1/2 the RF is radiated in the
first half wave (bottom two elements). 1/4th is radiated from the
next half wave. 1/8th from the next dipole, and so on. By the time
what's left gets to the top element, there's not much left. With all
the RF coming from the base of the antenna, and with the uptilt
problem, it's often best to mount the antenna in an inverted position.

I have an NEC2 model somewhere but it has problems. Sorry.

However, I do agree with the article's conclusions. It is a cheap
antenna to build.

As for the original question, ATLC is certainly the right answer for
modeling a rather unusual microstrip configuration. The program can
allegedly be built using Cygwin for Windoze. I haven't tried it:
http://atlc.sourceforge.net/installing.html
Note the spelling of Windoze on that page. I looked through the
ported package list, but didn't find ATLC.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558