The present disclosure relates to a pre-5th-Generation (5G) or 5G communication system to be provided for supporting higher data rates Beyond 4th-Generation (4G) communication system such as Long Term Evolution (LTE). An antenna for decreasing a signal loss caused by a dielectric loss in an antenna by decreasing a space of the antenna in a wireless device and improving performance of the antenna is provided. The antenna includes a first radiator, and a second radiator installed on a cover of the wireless device to radiate a radio signal radiated by the first radiator, the second radiator separate from and facing the first radiator.