<p>Passive elements (5) in each of passive element arrays (6) have a strip shape substantially parallel with the longitudinal direction of a dipole antenna (4) and formed with prescribed gaps (L5). The gaps (L5) are set to less than 1/8 of the wavelength ? of a high-frequency signal that is supplied to a supply line (20). The passive element arrays (6) are arranged so as to form a plurality of pseudo-slot apertures (S6) whereby electromagnetic waves are propagated as a magnetic current from the dipole antenna (4).</p>
