I just picked up the August
2004 edition of Microwave Journal and see there
is a major feature article on beam-forming antennas
that you might be interested in reading.
Here's a link to the article, but you might need
to sign in to access it:
http://www.mwjournal.com/getblob.asp?fu ... 8mwj33.pdf
- Kirt Blattenberger