;With increasing frequency, the loss of electromagnetic wave propagated in air also gradually increases. Therefore, higher-gain antenna is required to compensate path loss when energy propagates through the air. Transmitting the signal accurately to the users and reducing the antenna radiation energy to pass in an unnecessary direction can reduce unnecessary consumption of energy and interference with other users. The switching antenna array using many antennas has an advantage in improving gain. Furthermore, it has multiple inputs. When one of the inputs is excited, the main beam in a specific direction can be formed. Therefore, the switching antenna array has different main beam directions corresponding to different input signals. This thesis proposes a design of modified switch antenna array for the fifth-generation mobile-communication Korea′s tentative high-frequency band (28 GHz) and military band (10 GHz), using modified couplers to make switched antenna array with different directions from traditional Butler radiation. Using the modified coupler, a dual-beam switching array of ±18 deg, and a four-beam switching array of ±9 deg and ±49 deg can be fabricated.
