quad band microstrip antenna design

i am designing an quad band microstrip antenna with (698-806Mhz) and(1710-2155Mhz) using CST software....and my required bandwidth is around 14% ..i am not able to get the required bandwidth .can any one please help out how to increase the bandwidth.
thank you ..

There are multiple ways to increase the bandwidth of a microstrip antenna: increase the height of the substrate, decrease the dielectric constant, adding parasitic elements, loading with reactive elements, etc.