The disclosure relates to an array antenna, and more specifically, the array antenna configured by arranging a plurality of antenna elements at close positions. An array antenna is provided. The array antenna includes a first antenna operating in a first mode, and a second antenna operating in a second mode, wherein a correlation between an electric field of the first mode and an electric field of the second mode falls below a first threshold which is predetermined, or a correlation between a magnetic field of the first mode and a magnetic field of the second mode falls below a second threshold which is predetermined.