An electronic device, comprising: a housing comprising a first plate extending in a first direction and a second direction and a second plate parallel to the first plate and configured to form a space between the first plate and the second plate; a side member configured to enclose at least a portion of the space; a display (160;703) disposed within the housing and exposed through the first plate; a printed circuit board, PCB, disposed within the housing and disposed between the display (160, 703) and the second plate; and a communication module disposed within the housing and coupled to the PCB, wherein the side member comprises: a first conductive member extended along a periphery of the space; a second conductive member extended along the periphery of the space in parallel to the first conductive member, wherein the first conductive member is spaced apart from the second conductive member, the first conductive member is closer to the second plate than the second conductive member, and at least a portion of the first conductive member is electrically connected to the communication module; and a first insulating member extended along the periphery of the space in parallel to the first conductive member and disposed between the first conductive member and the second conductive member, and characterized in that, in a cross-sectional view of the electronic device, the cross-sectional view having a cutting plane perpendicular to the first plate and the second plate and parallel to the second direction, a dimension of the first insulating member along a third direction perpendicular to the first direction and the second direction is enlarged starting from an outer periphery of the electronic device towards the inside of the electronic device. a housing comprising a first plate extending in a first direction and a second direction and a second plate parallel to the first plate and configured to form a space between the first plate and the second plate; a side member configured to enclose at least a portion of the space; a display (160;703) disposed within the housing and exposed through the first plate; a printed circuit board, PCB, disposed within the housing and disposed between the display (160, 703) and the second plate; and a communication module disposed within the housing and coupled to the PCB, wherein the side member comprises: a first conductive member extended along a periphery of the space; a second conductive member extended along the periphery of the space in parallel to the first conductive member, wherein the first conductive member is spaced apart from the second conductive member, the first conductive member is closer to the second plate than the second conductive member, and at least a portion of the first conductive member is electrically connected to the communication module; and a first insulating member extended along the periphery of the space in parallel to the first conductive member and disposed between the first conductive member and the second conductive member, and a first conductive member extended along a periphery of the space; a second conductive member extended along the periphery of the space in parallel to the first conductive member, wherein the first conductive member is spaced apart from the second conductive member, the first conductive member is closer to the second plate than the second conductive member, and at least a portion of the first conductive member is electrically connected to the communication module; and a first insulating member extended along the periphery of the space in parallel to the first conductive member and disposed between the first conductive member and the second conductive member, and characterized in that, in a cross-sectional view of the electronic device, the cross-sectional view having a cutting plane perpendicular to the first plate and the second plate and parallel to the second direction, a dimension of the first insulating member along a third direction perpendicular to the first direction and the second direction is enlarged starting from an outer periphery of the electronic device towards the inside of the electronic device.