increasing the band width of microstrip antenna

Hi guys,
I am designing a microstrip antenna for S band i.e (3.1Ghz - 3.5Ghz) in IE3d required bandwidth is 12% but i am able to simulate only 6% i tried

a. Increasing substrate thickness and reduced Er
b. Added a slot

but these two techniques did help but bandwidth increased to say 1% more and more over i have to design a 4 element patch array for the same bandwidth which when i implemented i got a strange output the Bandwidth decreased from 6% to 3% sooooooo plssssssss helpppp wat should i do