A novel varactor loaded unit cell for reconfigurable single-layer reflectarray antenna is proposed in this work. The unit cell consists of a varactor loaded conducting pattern printed on the substrate over a ground plane. The phase of the reflected wave is varied by changing voltage across the varactor diode. By tuning varactor diode between 0.02 pF to 0.25 pF we can achieve the phase agility of 360° at the design frequency of 11 GHz. Despite single layer, the unit cell shows excellent characteristics in terms of phase range, figure of merit, reflection loss, and bandwidth. The proposed unit cell has a unique and novel geometry which attributes to its excellent radiation characteristics. The designed unit-cell structure is a good candidate for low cost and low profile reconfigurable reflectarray antenna designs.