This paper investigates and designs a 5 GHz wireless router antenna based on phased array technology. With the advancement of wireless communication technology, the 5 GHz band has become essential for high-speed data transmission and low-latency communication. However, signals in this frequency band are susceptible to attenuation and obstruction by walls, limiting communication quality and coverage. Phased array technology optimizes signal transmission by dynamically adjusting the beam direction, overcoming the limitations of traditional antenna designs. This paper first introduces the principles and advantages of phased array technology, then details the design process of the 5 GHz wireless router antenna, including determining the fundamental parameters of the array antenna, testing and adjusting microstrip antenna elements, and conducting array generation and simulation analysis. The results show that the designed phased array antenna performs well in terms of bandwidth characteristics, sidelobe levels, and directivity, meeting the performance requirements of modern wireless routers. Finally, this paper summarizes the advantages and disadvantages of phased array antennas and discusses future improvements, including enhancing element performance, improving beamforming techniques, and reducing system cost and power consumption.