The uniform planar arrays interlacing the nonsidelobe endfire array and the nonsidelobe broadside array are described. This planar array has two uniform spacings, i.e., one is

on the endfire array axis and the other is

on the broadside array axis, where

and

are the number of elements on each array axis. The resultant patterns are unidirectional having a mainlobe and two small sidelobes decreasing with the number of elements, so these planar arrays may be considered as an improvement of the well-known four-element planar array. To serve the convenience of the planar array constructions the nomograms among the beamwidth and the given number of endfire and broadside elements are illustrated. From these nomograms it follows that the beamwidth of the pattern depends mainly upon the number of elements on the broadside array axis.