A simple and novel polarization-dependent phase gradient metasurface (PGMS) is proposed to synthesize a flat-top radiation pattern by dividing the metasurface (MTS) into multiple regions. Each sub-region generates a beam in a particular direction and multiple beams with different directions form a flat-top pattern in the far-field. A flat-top pattern in a single and 3D plane are realized by dividing the MTS into two and four regions, respectively. The proposed MTS consists of a multi-layered elliptical geometry encircled by a square loop. The elliptical shape of the unitcell offers polarization dependent behavior and produces dual-band characteristics for different incident wave polarizations at 10 and 12 GHz. Two microstrip patch antennas operating at 10 GHz and 12 GHz are placed at the focal point of the MTS. The simulated flat-top beamwidths in a single plane with a 1 dB ripple are 36˚ and 34˚ at 10 and 11.8 GHz respectively. Similarly, in 3D space, the beamwidths are 33˚ and 31˚ at 10 and 11.8 GHz, respectively. Both simulated and measured results are presented for 3D flat-top patterns.