A novel approach for generating a circularly polarized microstrip reflectarray with variable size rectangular microstrip elements is presented. The concept was implemented with a linear feed-horn illuminating microstrip dipoles which are arranged in a non-overlapping perpendicular configuration in the lower Ka-band (20 GHz) and as crosses (overlapping dipoles) in the upper Ka-band (30 GHz). Experimental results indicated that the perpendicular CP array had a peak efficiency of 31.2% with a 3 dB Axial Ratio bandwidth of 6%. In addition, we observed that both LP and CP could be achieved by simply changing the orientation of the feed-horn with respect to the reflectarray elements.