ANTENNA

摘要

An antenna the manufacturing cost of which can be reduced by determining the minimum number of element antennas required to suppress the unwanted side lobe. The antenna comprises a plurality of element antennas (1) arranged on a plurality of imaginary concentric circles (2) of different radii on a plane and forms a beam in a direction inclining by at most theta >0< from the direction perpendicular to the plane. If the radius of n-th concentric circle (2) from the inside is a>n<, the number of element antennas (1) arranged on the n-th concentric circle (2) from the inside is M>n<, and the wave number is k, the number M>n< of the element antennas (1) arranged on each concentric circle (2) is determined to satisfy the following condition, M>n<+0.81•M>n<?1/3>>k•an•(1+sin theta 0)and the element antennas (1) are arranged, at substantially regular intervals, in the circumferential direction of each concentric circle (2) .