Abstract: A planar multibeam array realized by modified B ulter phase network is provided.The array is made up of four omnidirectionnal an t ennas.Its pattern can be controlled by changing feeding port,and it will complet ely cover the horizontal surface.The directional resolution is 90 degree,and can be improved to 45 degree when using distribution network.This kind of array can be used for base station or mobile station,and for the approximate estimation o f DoA(Direction of Arrival)also.