Need help for simple circular patch antenna design

hi all
This will just take a minute to solve my problem but I am very confused here.
I am following a paper, I do just like them as instructed in the paper but my antenna is not radiating. I have done everything same. But I cannot have 8db gain. I have -7db :(
Freq:4.7GHz
Ground: 48/48mm
Substrate: 48/48/0.25mm (FR4)
Patch: radius=16.9mm, (copper)
Transmission line: 0.841, 9.(copper)
they didn't mention about port so I draw a lumped port
+airbox+etc...everything
Thanks all

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