The present disclosure relates to a communication technique for converging Internet of Things (IoT) technology with a 5th Generation (5G) communication system for supporting a higher data transfer rate beyond a 4th Generation (4G) system, and a system therefor. The disclosure can be applied to intelligent services (e.g., smart homes, smart buildings, smart cities, smart or connected cars, health care, digital education, retail business, and services associated with security and safety) on the basis of 5G communication technology and IoT-related technology. An antenna module is provided. The antenna module includes an antenna, and at least one transmission line configured to transmit a first signal through the antenna for transmission or receive a second signal through the antenna for reception. The length of the transmission line may be determined based on the impedance when the first signal or the second signal flows through the transmission line.