An electronic device is provided. The electronic device includes a housing including a first plate facing in a first direction, a second plate opposite to the first plate and facing in a second direction, and a side member enclosing a space between the first plate and the second plate, an antenna structure including at least one antenna element disposed substantially parallel to the second plate in the space and disposed to face the second plate, a conductive structure disposed in the space and including an opening, the antenna structure being disposed to at least partially overlap the opening when viewed from above the second plate, and a wireless communication circuit configured to form a directional beam through the at least one antenna element. In addition, various embodiments may be available.