Patent ID: 7057573

Claim:
A method for controlling an array antenna, said array antenna comprising: a radiating element for receiving a radio signal; at least one parasitic element provided apart from the radiating element by a predetermined distance; and a variable reactance element connected to the parasitic element, thereby changing a directivity characteristic of said array antenna by changing a reactance value of said variable reactance element for operation of said variable reactance element as either one of a director and a reflector, wherein said method includes a step of calculating and setting the reactance value of said variable reactance element for directing a main beam of said array antenna in a direction of a desired wave and directing nulls in directions of interference waves on the basis of a received signal received by said radiating element so that a value of an objective function expressed by only the received signal becomes either one of the maximum and the minimum by using an iterative numerical solution of a nonlinear programming method.