Coupler Integrated Microstrip Patch Linear Phased Array for Self-Calibration

In this letter, a coupler integrated microstrip patch linear phased array is proposed as a new self-calibration system. The proposed coupler placed along the edge of the microstrip patch antenna is weakly coupled to the antenna array. This allows self-calibration without affecting the radiation performance of the antenna array. A 1 × 4 coupler integrated patch linear phased array and a beamformer operating at 5.8 GHz were implemented to verify the new self-calibration system. The measurement result using the self-calibration is very close to the result with a vector network analyzer (VNA). The coupler integrated patch linear phased array proposed as a new self-calibration system has 0.22 dB root-mean-square error (RMSE) magnitude and 1.2
$^{\circ }$
RMSE phase. The calibration method using a proposed antenna array is expected to on-site calibration.