Patent ID: 6768475
Filing Date: 2004-07-27
Classification: H01Q

Abstract:
An antenna apparatus in which a plurality of element antennas are arranged on a plurality of concentric circles assumed to exist on a plane and differs in radius from each other, and which performs a beam-forming in a direction inclined by &thgr;0 at the maximum from a direction perpendicular to the plane,said antenna apparatus being characterized in that if the radius of the n-th concentric circle from the inner side is an; the number of element antennas arranged on the n-th concentric circle from the inner side is Mn; and the number of waves is k, the number Mr of element antennas arranged on each concentric circle is determined so as to satisfy the following equation: Mn+0.8Â·Mn1/3>kÂ·anÂ·(1+sin &thgr;0) and in that the element antennas are arranged on each concentric circle by being generally equally spaced apart from each other in the circumferential direction of the concentric circle.