The present invention relates to: a communication technique for merging, with IoT technology, a 5G communication system for supporting a data transmission rate higher than that of a 4G system; and a system therefor. The present invention provides an antenna module comprising: an antenna array for radiating beams through a top surface thereof, a dielectric disposed to be spaced apart from the top surface of the antenna array by a first preset length; a first reflector comprising a metallic material, and disposed to be spaced apart from the bottom surface of the dielectric by a second preset length; and a second reflector comprising a metallic material and disposed in the partial region of the bottom surface, of the dielectric, which faces the top surface of the antenna array.