In this paper, we present the design of an integrated circularly-polarized high-gain antenna with a broad bandwidth at the millimeter-wave Ka-band. The proposed compact antenna is enabled by the integration of a metasurfaces-based transmit-array and a broadband circularly-polarized feed radiator. The feed radiator is a substrate integrated waveguide fed patch with a finite-sized metasurfaces superstrate, while the transmit-array utilizes the rotation phase for collimating the waves emitted from the feeding source. The full-wave simulation results show that the integrated transmit-array antenna achieves an overall bandwidth of about 18.3% within which the S 11 is below −10 dB, the axial ratio is smaller than 3 dB, and the gain variation is less than 3 dB with a peak gain of 23.5 dBi.