A metamaterial-based wideband circularly polarized (CP) phased array antenna is developed. An 8x8
antenna array prototype using 5-bit RF phase shifter demonstrates a scan angle of ±30°, scan resolution of 3.5°, scan loss of 1.5 dB, boresight gain of 22 dBic, active reflection coefficient less than -9 dB, axial ratio less than 3 dB, and side-lobe levels less than -10 dB from 27 GHz to 30 GHz.