An electronic device includes housing including first plate, second plate, and side member, wherein side member includes first side face in first direction having first length, second side face having second length greater than first length, third side face extending parallel to first side face having first length, and fourth side face; touch screen display disposed within housing, and exposed through portion of first plate; a PCB between first plate and second plate to be parallel to second plate, wherein PCB includes ground plane and first L-shaped ground extension between first conductive region of second plate and first plate, and first L-shaped ground extension includes first portion extending in second direction from ground plane and second portion extending in first direction from first portion; and at least one first wireless communication circuit disposed on PCB and electrically connected to first point in second portion of first L-shaped ground extension.