An electronic device is provided. The electronic device includes a millimeter wave (mmWave) antenna including a plurality of conductive patches, a wireless communication circuit, and a radio frequency (RF) cable electrically connecting the mmWave antenna to the wireless communication circuit. A first portion of the RF cable includes a base dielectric, a metal plate disposed on one surface of the base dielectric, and a shielding film including a first region in contact with the metal plate, a second region spaced apart from the metal plate by a first height, and a third region configured to connect the first region and the second region, at least one waveguide is formed by the second region, the third region, and a portion of the metal plate, and the wireless communication circuit transmits and/or receives RF signals corresponding to the plurality of conductive patches through the at least one waveguide.