Fabry-Perot cavity(FPC) antennas with artificial magnetic conductor(AMC) surface are designed in order to provide scan capability by $4{ imes}1$ array feed inside the cavity. The proposed antenna, excited by $4{ imes}1$ thinned array, not only achieve higher directivities but also improve suppression of sidelobe level(SLL) relative to that of the thin array alone. The FPC antenna with the height of a quarter wavelength generate maximum gain of 19 dB, SLL suppression of 14 dB and maximum scan angle of $8^{circ}$ under the feed phase difference of $90^{circ}$ at the design frequency of 12 GHz.