Abstract: We designed an ultra-wideband Vivaldi antenna and simulated its 16×16 array based on the optimal subarray scheme designed according to the division. The beam deflection of the antenna array was analyzed by uniform weighting and low sidelobe weighting. Beam scanning analysis was conducted from different frequency points and deflection angles. The difference beam and shaped beam of the antenna was simulated and analyzed, and good results were got. At the same time, sensitivity analysis was conducted for the first time on disturbances at the subarray level. It is found that under different phase interferences, the larger the interference range, the greater the impact of phase interference on the main lobe beam, and the more significant the decrease in main lobe gain and the increase in sidelobe level. The same conclusion applies to amplitude interference and amplitude phase interference. In practical applications of irregular subarray antennas, the phase error at the subarray level has little impact on the overall antenna performance within a certain range. The amplitude error at the subarray level has a significant impact on the overall antenna performance. Overall, the impact of sub array level interference on the scanning angle is not significant, and the impact on the main beam increases with the increase of interference range. The simulation analysis in this article can provide reference for the design and processing of irregular subarray antennas, which will enrich the field of irregular subarray antenna design simulation and performance analysis, and save practical processing and application costs.