Angle of arrival estimation embedded in a circular phased array 4 × 4 MIMO antenna

To ensure the success of upcoming connected car systems, we are currently developing a 4 × 4 multiple-input multiple-output (MIMO) antenna system that utilizes circular phased array technology. The angle of arrival (AOA) estimation is embedded into the circular phased array antenna so that the AOA functions are concurrent with the MIMO system. The AOA antenna employs an RF-based interferometric monopulse technique without the use of a Butler matrix, which leads to less hardware complexity. In this study, we focus on the methodology and basic characteristics of the AOA system after a brief explanation regarding the configuration of the whole antenna system.