cp antenna

I am looking for a simple single-layer coaxial probe fed circular polarized MS antenna.
The main problem is 3-4% band of WSVR and AR. I tryed many designs with some deformations of the ground, holes/slots in it, feeding with 2 or 4 probes in quadrature etc., but I could not made antenna with brodband WSVR and AR at the same time! All designs have band of AR not more than 1-1.5%(level AR = 50%)... I saw some antennas with good parameters, but they use air dielectric, when I try epsilon more than 1 - all characteristics have deteriorated, I get narrow band...
I can not use array of MS radiators bacause of the limited dimensions..
Is there any solution of this problem?
Thank you!

hi there...
you can simply view the hfss version 9 or 10 book as it has a simple probe feed patch antenna.....and yes it is certain that patch antennas are narrowband limited but there are different techniques for making it a broad band.....you can either make it multilayer but as that is not your concern so you can also try altering the shape of the patch or the ground....or as you have already tried the slots method....there are many ieee papers on this topic of broad band patch antenna ....you search in googe and will find many other techniques.....

Can you recommend something more concrete? I did not find any papers about CP antenna with broadband AR and WSVR at the same time...