A 5.8 GHz Array Antenna Based on 4x4 Butler Matrix for Beamforming in 5G Network

Due to the fast development of the fifth-generation (5G) wireless network and high-speed data communications, a vast number of Internet of Things (IoT) sensors have been deployed most of them battery powered. Utilizing wireless energy harvesting techniques to power up IoT sensors eliminates the constraints of batteries and their limited lifetime as an energy source. A multi-beam array antenna has the potential to focus the radiation to the desired location and provide an adequate amount of energy to turn on a low-power IoT sensor. In this paper, a new 4x4 Butler matrix beamforming network is designed on FR-4 material which is connected to a 2x4 microstrip array patch antenna at a 5.8 GHz frequency. Each output of the Butler Matrix can provide power to two antenna elements simultaneously. The array antenna and Bulter Matrix network are designed and simulated in COMSOL Multiphysics tools. The simulation results indicate that the Butler matrix equally divides the voltage of -6 dB to all output ports when the input ports are excited. The array antenna represents the maximum effective radiated power of -11dB at 5.8 GHz. The maximum antenna gain is 28 dBi with a radiation efficiency of 86 %.