An electronic device is provided. The electronic device includes a housing and an antenna radiator disposed in the housing. An opening is formed in the housing. The opening includes a first portion configured to align with a length direction of the antenna radiator at a position corresponding to the antenna radiator and penetrate the housing in a thickness direction, and a second portion connected to the first portion, the second portion being configured to form a specified angle with respect to the length direction of the antenna radiator and penetrate the housing in a thickness direction. At least a portion of the housing, which surrounds the opening, comprises a conductive member. At least a portion of a circumference of the opening comprises an electrical open curve.