This letter presents the design of wideband, low-cost, single-layer, ultrathin, beam-scanning circularly polarized reflectarray (CP-RA) antenna with high-radiation characteristics. To obtain efficient single and multiple CP beams, a subwavelength unit cell based on Pancharatnam-Berry (PB) geometrical phase was used to increase the beam scanning efficiency. PB unit cell with periodicity of 0.28λo and ultrathin thickness of 0.11λo is used to achieve the required phase correction across the reflectarray aperture to produce a collimated right-hand circularly polarized (RHCP) beam in the desired direction. The unit cell has three plasmonic resonances and the proposed CP-RA consists of 43 × 43 PB unit cells and occupies an area of 215 × 215 mm 2 . Both simulation and experimental results show that the proposed CP-RA produces RHCP pencil-beam in the desired direction with a 1 dB gain bandwidth (BW) of 24.5