In this paper the procedure of preliminary design of Multifunction Array Radar (MFAR) is studied and a new criterion called Beam-width criterion is introduced moreover its benefits will be pointed out. These advantages are applied to reduce the average power of the radar transmitter. Using the
solution to a general sample problem, the impact of this criterion on the average power will also be studied. It is shown that this method provides some flexibility for local minimization of the array size
