An electronic device includes a housing that includes a first plate, a second plate facing a direction opposite the first plate, and a side member surrounding a space between the first plate and the second plate, an antenna structure that includes a plurality of dielectric layers perpendicular to the side member and parallel to the first plate, a first array of conductive plates aligned in a first direction perpendicular to the first plate at a first dielectric layer of the dielectric layers, a second array of conductive plates spaced from the first array and aligned in the first direction at the first dielectric layer, wherein the second array is farther from the first plate than the first array, at least one ground plane positioned on at least one of the dielectric layers and interposed between the first array and the second array, when viewed from above the side member, and a wireless communication circuit electrically connected to the first array and the second array and configured to transmit and/or receive a signal having a frequency in a range of 20 GHz to 100 GHz.