The aim of the research is to determine the characteristics of an ultra-wideband array scanning antenna composed of wire radiators. The array element is a 3D Vivaldi antenna. Numerical simulations of an individual Vivaldi radiator and an array of such radiators were carried out, using the method of integral equations in the thin-wire approximation and with the help of the original program and the simulation program MMANA. The dimensions of individual radiating elements have been determined according to the matching criterion (SWR<2) and the shape of the radiation pattern when operating in the frequency range (2–18) GHz. The antenna model described according to the matching criterion has a frequency overlap ratio equal to 12. The degree of decreasing of the frequency band of the individual radiator was determined when it is located within an array that does not scan and within an array that scans within an angle of 30o. In the article, the frequency characteristics of the array antenna were studied in relation to the radiator parameters and to the phase-scanning capability. It has been shown that the largest matching frequency range is possessed by the array that has the lowest spacing of the radiators. In a planar antenna array, when scanning in the H-plane, the frequency range according to the matching criterion is reduced by (2–3) times. It is shown that the linear array without scanning has a frequency overlap ratio equal to six according to the radiator matching criterion. This ratio decreases as the phase scan sector increases. In a planar array, the frequency band and the phase-scan sector overlap ratio are lower than in a linear array and decrease as the number of rows increases. The given array antenna has a number of design advantages and can be used in systems with ultra-wideband signals.