PURPOSE: To realize the antenna system having a suppression performance even to plural interference waves (undesired waves) with respect to the antenna system having a function to suppress the undesired signal made incident from a side lobe of a main beam.

CONSTITUTION: The electric characteristic of a receiver connecting to an antenna of the antenna system is made equivalently identical and the dispersion in the amplitude and phase of a receiver output signal are corrected respectively by a compensation device 11 so that the reception is not equivalently modulated by noise and the result is inputted to a Fourier transformation device 10 thereby almost discriminating plural interference waves (undesired waves) by each incident direction. Thus, a weight adjusted by an adaptive filter 5 receiving an output of the Fourier transformation device is converged quickly to an optimum solution and even when the plural interference waves (undesired waves) are received, the antenna system having an interference wave suppression performance is realized.