In this article, a broadband circularly polarized (CP) reflectarray (RA) is presented. A Ka-band multilayer-CP RA antenna is designed and further validated through measurements. The two orthogonal slot arms are angularly rotated for the phase compensation in the RA design. A 25 × 25 RA with a physical area of 90 × 90 mm2 (9 × 9 λo2) is designed for broadside radiations. The elements at an RA surface are excited by a wideband CP horn. An excellent CP performance is achieved with broadband matching and 3-dB axial ratio covering the entire band.