Antenna and electronic device including same

An electronic device comprising:

• a housing at least partially comprising a support member including a plurality of recesses;
• an antenna structure disposed in an inner space of the housing, the antenna structure comprising:
• a substrate having a first substrate surface facing a first direction and a second substrate surface facing a second direction opposite the first direction, and being disposed so as to correspond to the support member, the substrate configured to have a first dielectric constant,
• a plurality of antenna elements disposed at the substrate and configured to form a directional beam in the first direction, and
• at least one dielectric disposed on the first substrate surface and configured to have a second dielectric constant, at least a portion of the at least one dielectric being disposed so as to be seated in at least one of the plurality of the recesses of the support member;
• and
• a wireless communication circuit disposed in the inner space and configured to at least one of transmit or receive a wireless signal in at least one frequency band through the plurality of antenna elements.