Array antenna apparatus

An array antenna device. Planar array antenna of the present invention (10) comprising a dielectric substrate (11), strip conductor (12), an annular element (14a ~ 14e) and a conductor plate (13). Strip conductor (12) and the conductor plate (13) constituting the microstrip line. An annular element (14a ~ 14e) is formed with a strip conductor formed on a surface (12) of the dielectric substrate (11) every other interval (D) are arranged. An annular element (14a ~ 14e) having a circular opening portion of the notch and a circumference of approximately one wavelength open loop configuration. Strip conductor (12) and the annular element (14a ~ 14e) electromagnetically coupled. Planar array antenna (10) the annular element operates as the radiating element.