I have a 1.8 Ghz microstrip antenna. I need to turn this into an array microstrip antenna, but I can't. Can you help?

 

Hello there welcome to AAC!
So little information this is the best I can do for you and I'm using my crystal ball.
If you reduce the width of the patch, the radiation conductance is insufficient to match the input. You can usethe microstrip patch as a transmission line and connect a
line opposite the feed to lead to other patches. If you space the patches by half wavelengths, the impedances of the patches will add in phase at the input, because it rotates once around the Smithchart in lambda/2. The
Characteristic impedance of the connecting lines has no
effect at center frequency. The junction of transmission- line
feeder and the patch introduces extra phase shift .The difference in phase between two adjacent elements in
series-fed array as given

Where, f=frequency of the electromagnetic signal,
l =length of line connecting adjacent elements,
v = velocity of propagation, and
¸λ = signal wavelength. The main
limitation in series-fed arrays is the large variation of the
impedance and beam-pointing direction over a band of frequencies.