broadband patch antenna at 5.7 GHz?

trying to make a broadband patch antenna 5.6 to 5.9 Ghz, probably on 62 mil thick FR4 board. I am close, but just can not get the final dimensions to give good VSWR across the whole band. Only getting maybe 6 dB return loss over the band on an E-shaped patch. It is really touchy, and each analysis pass takes a while...I may never converge on the final correct dimensions. (yes, I know it would be easier on a thicker substrate, or lower dielectric constant--like air, but I need it to be "cheap" and very manufacturable for a commercial job)

Anybody have dimensons on such a beast?

Any usual patch antenna exhibits resonant behaviour, so it cannot be used (and is not matched) over a wider band. I would try to use a bow-tie shaped antenna on a dielectric support. Or, for very wide bandwidth, there are some UWB antenna designs.
I do not work in that area but Microwave Journal and Microwaves & RF magazines brought interesting antenna designs over last 3-5 years.

Maybe you need more elements. I saw one my colleague designed such antenna with 1024 elements, and got about 20dB return loss.

the E shaped patch has 2 resonant frequencies, so you can make a double tuned vswr response.

Just another idea. U-shape slot antenna can get wide bandwidth.

http://www.accessengineeringlibrary....6855_ar016.pdf