This paper presents a reflectarray antenna featuring a reflection-type horn feed, designed to deliver enhanced radiation performance in both the Ku and Ka bands. The antenna employs a precisely engineered phase distribution across the reflectarray elements, enabling accurate control of beam direction and radiation pattern. Simulation results demonstrate realized gains of 16.88 dBi at Ku and 28.5 dBi at Ka band. The antenna exhibits excellent impedance matching, with a scattering parameter (S11) of-21.99 dB at 11.77 GHz and a bandwidth of 970 MHz (centered at 12 GHz). At 28 GHz, the antenna maintains low S11 values, indicating good impedance matching across a broad frequency range.