Planar and Circular arrays have large potential in many applications, including RADAR. Many critical polynomials arc used to synthesis the antenna array for improved directivity and sidc-lobe level reduction. However, there is no unique simulation tool to present the design and synthesis of planar and circular arrays. Most of the EM numerical solvers (GST, HFSS. etc) have been used to simulate the 3D structure of antenna: however they are not useful of design or performance trade-off. For the first time, we developed a tool of design and synthesis various antenna arrays, including critical circular arrays, called ARRAY TOOL. In this paper, we present the concept and use of ARRAY TOOL. We have shown the strategics followed to design linear, planar and circular arrays with uniform and random distribution. Also the numerical analysis of linear, planar and circular arrays, its various array excitation and its radiation pattern characteristics are studied. © Research India Publications.