This paper presents a high gain circular polarized Fabry-Pérot antenna for CubeSat applications. A key idea is the implementation of cavity using a 5× 5 Metasurface ground surface to improve the total gain of the proposed antenna design. The two opposite corners of the radiating patch elements are truncated to achieve a right-hand circular polarisation (RHCP). The presented simulation results show that the proposed antenna provides a high gain of 9.4 dBi, -10 dB bandwidth 12% (2.42-2.73 GHz) with a reflection coefficient of -15.6 dB at 2.5GHz and a -3dB axial ratio bandwidth of 1.6% at 2.5GHz.