Abstract: In order to meet the requirement of ultra-wideband (UWB) electronic system, the strong mutual coupling UWB antenna element and array are investigated in this paper. Firstly, the antenna element is designed to satisfy the linear polarization and the strong coupling. Then the UWB phased antenna array is studied, and the array consisting of 10×10 antenna elements is designed. The high frequency electromagnetic field simulation software is used to compute the infinite large period array in the 2D periodic environment. The function of the UWB arrays under 2D periodic boundaries can be realized with limited size. Meanwhile, the problem of full array simulation of ultra wideband infinite dipole phased array with strong mutual coupling effect is solved. To make array element work more effectively, we further study the gradient Barron feeding structure on the basis of analysis of the antenna unit structure design in detail. The feed method is optimized by combining the gradient structure and the strong coupling UWB antenna unit to achieve the effect of UWB feed. Finally, the antenna array sample is fabricated and tested at the different frequency in the microwave chamber, and the results agree well with the simulation data. The test results show that the main surface radiation pattern beam peak gain in the maximum scan angle at different frequency are greater than 5 dBi, up to 20 dBi maximum, which meets the design requirements. Thus, the designed array antenna can be applied to actual microwave system.