Something to keep in mind is that phased arrays with a large number of
elements are simpler in one respect than ones with just a few elements.
In the first case, you can make the assumption with reasonable accuracy
that the feedpoint impedances of all elements are the same, since all
are in essentially the same environment with respect to the other
elements. For most simple phased arrays, you can't make this assumption.
So while pattern analysis of simple phased arrays is easy once you
assume equal element currents, actually getting those currents can be
more difficult than you might assume. If you're interested only in the
patterns and not how you'd actually get the currents you need, simple
trig is enough. But that's not enough to enable you to actually design
and build one that'll work as planned. Chapter 8 of the _ARRL Antenna
Book_ describes what has to be done to make simple arrays work properly,
as well as describing a few common simple arrays. There are also a few
examples of phased arrays with the free EZNEC demo (http://eznec.com),
where you can save yourself the math and immediately see the effect of
changing element currents.

Roy Lewallen, W7EL

David Harper wrote:

Thanks! You know any simple phased array configurations that are easy
to mathmatically model? I've played with a 4-element array all
located on the same axis just for fun to see what resulted (and to
make sure my equations were right), but I'd like to find some
real-world systems (hopefully without too many elements) to play with.
Any digrams exist on the net? (dimensional relationship between
elements, etc).

Thanks again!
Dave