Circular Microstrip antenna array

Hi

I have designed a circular microstrip antenna for x-band application (10-11.5 GHz) with short pin and coax feed. I'd like to redesign it in 2X2 array but I don't know how can I design the circular microstrip antenna with inset feed. So I need your help to give me some ideas how to convert the type of feed from coax. to inset feed for circular microstrip antenna and how can I design like this array.

Thanks in advance

hi
the article
Circular Patch Microstrip Array Antenna for KU-band

has detials on
-- THE DESIGN ISSUE OF CIRCULAR PATCH
MICROSTRIP ARRAY ANTENNA
-- FEED NETWORK DESIGN

this article can download from the following link
www.waset.org/journals/waset/v48/v48-49.pdf

Thanks for help...I have seen this paper and I found that the bandwidth is narrow and for my application I need 1.6 GHz.

Regards