Matching for a simple square patch antenna

Afterfewdays of trying, i still couldnt get the the matching to work. here are the steps that i've done.

1. find the impedance of the patch
2. through z matrices, i add a small patch to eliminate the imaginary part of the patch, and label it as Zl'.
3. using Zt=(Zo x Zl'), where Zo = 50ohm, I obtain the width of the QW feedline required.

Based on the result, i've obtained a total impedance approximately of 49+j1 impedance. I supposed this is a matched patched antenna, but the problem is that, my total efficiency simulated keep on getting -5db which is not good.


i've attached the cst file. any help is appreciated

hi znzn
to a patch antenna,what's the meaning of the "patch".can u give me a simple explanation about it?

microstrip patch antenna to be exact