An electronic device comprising: a conductive member including a first conductive plate and a second conductive plate extending from the first conductive plate while forming a first angle with the first conductive plate, wherein the first conductive plate and the second conductive plate form a cavity, which is open in a first direction perpendicular to the first conductive plate; a first and second radiation part (120, 130) provided on opposite sides of the first conductive plate and spaced apart from the first conductive plate by respectively a first and second distance (d1, d2), said second distance being a value allowing the second radiation part to be coupled to the conductive member, wherein the second radiation part is coupled to the conductive member; at least one wireless communication circuit configured to feed power to the first radiation part and the second radiation part; and a processor electrically connected to the wireless communication circuit, wherein the processor is configured to allow the wireless communication circuit to: receive a signal having a first frequency having a directionality in the first direction based on the first radiation part and the cavity formed by the conductive member operating as a reflector for the first radiation part; and receive a signal having a second frequency based on coupling between the second radiation part and at least a portion of the conductive member; and receive a signal having a third frequency and its second and third harmonics based on coupling between the second radiation part and the at least a portion of the conductive member; wherein the third harmonic of the third frequency is adjacent to the second frequency. a conductive member including a first conductive plate and a second conductive plate extending from the first conductive plate while forming a first angle with the first conductive plate, wherein the first conductive plate and the second conductive plate form a cavity, which is open in a first direction perpendicular to the first conductive plate; a first and second radiation part (120, 130) provided on opposite sides of the first conductive plate and spaced apart from the first conductive plate by respectively a first and second distance (d1, d2), said second distance being a value allowing the second radiation part to be coupled to the conductive member, wherein the second radiation part is coupled to the conductive member; at least one wireless communication circuit configured to feed power to the first radiation part and the second radiation part; and a processor electrically connected to the wireless communication circuit, wherein the processor is configured to allow the wireless communication circuit to: receive a signal having a first frequency having a directionality in the first direction based on the first radiation part and the cavity formed by the conductive member operating as a reflector for the first radiation part; and receive a signal having a second frequency based on coupling between the second radiation part and at least a portion of the conductive member; and receive a signal having a third frequency and its second and third harmonics based on coupling between the second radiation part and the at least a portion of the conductive member; wherein the third harmonic of the third frequency is adjacent to the second frequency. receive a signal having a first frequency having a directionality in the first direction based on the first radiation part and the cavity formed by the conductive member operating as a reflector for the first radiation part; and receive a signal having a second frequency based on coupling between the second radiation part and at least a portion of the conductive member; and receive a signal having a third frequency and its second and third harmonics based on coupling between the second radiation part and the at least a portion of the conductive member; wherein the third harmonic of the third frequency is adjacent to the second frequency.