This proposal presents a high gain array antenna of double-ridged horn for X-band radar applications. The antenna array consists of 5184 radiating elements divided into 1296 subarrays, each subarray has 4 horn elements fed by a 4-port waveguide power divider in horizontal plane. The subarray is integrated with calibration signal to improve the system accuracy. The measurement results of 72×72 horn array in a bandwidth of 7% matching with the simulation results indicate an effective design approach: the design antenna has achieved a good active return loss (S₁₁) less than –10 dB when beamforming upto ±55⁰, a peak gain of 42.7 dBi, a pencil beam with half-power beamwidth (HPBW) less than 1.4⁰ in both E and H plane in the operating bandwidth.