Provided is a method for manufacturing an antenna which is minimized and used in a low frequency band. The method includes forming and preparing a radiator for an antenna, mounting the radiator inside a dam molding part including an upper dam molding part and a lower dam molding part, injecting a molding material into the dam molding part through an inlet provided at one side of the dam molding part, the molding material including a composite material with a controlled diameter and content, hardening the injected molding material, and separating the hardened molding material covering the radiator from the dam molding part. Accordingly, a miniaturized antenna can be provided, which can achieve a high integration density, prevent deformation of the radiator caused by external pressure generated in processes, and be used in a low frequency band by covering the radiator with a molding material having a high permittivity and a low-loss characteristic.