How to obtain the desired specs of rectangular patch antena using CST?

Hello everyone... I have a problem in designing rectangular patch antenna with following specs:
Resonant freq = 4.3 GHz
Bandwidth = 100 MHz
Radiation pattern = unidirectional
VSWR = less than 2
Return loss = less than -10dB
Gain = more than 10dB
Feeding = coaxial probe

Using the common formula, I got W= 27,578003mm and L=22,645751mm. After running a sim in CST, the result was like this:
Radiation pattern = unidirectional
VSWR = 9.4368
Return loss = -1,8487583 dB
Gain = 3 dB

I've tried to optimize it by changing the width and length of patch, but ended up in two conditions:
- Good gain, good radiation pattern, bad vswr, bad rl
- Bad gain, bad radiation pattern, good vswr, bad rl

My question is, what should I do in order to get the specs I desire? Thank you for your help. :)

Looking your return loss, the question arises about feeding. What feeding you doing, u can start with inset feed or quaterwavelength feed. And, try matching the feed impedance with the edge impedance of patch.