Research On Array-based Adaptive Beamforming And Nulling

The purpose of the adaptive beamforming and nulling antenna system is to adjust the amplitude and phase of the signals in each element path of the array antenna,so as to control the pattern of the array antenna adaptively according to the changes of the external environment of the system.The desired signal enters from the main beam and the interference signal enters from the nulling position of the antenna.This kind of intelligent beam control technology has received more and more attention in the field of wireless communication and navigation.This paper improves the traditional RF architecture based on vector multiplier nulling,and optimizes the system's completeness from the engineering point of view combined with the new adaptive beamforming and nulling algorithm.In order to ensure the normal operation of communication satellite under artificial or complex electromagnetic environment interference,a complex domain radio frequency frontend based on power detector is used to control the array signal in the channel.Each module's design idea is elaborated closely,and simplifies the architecture,reduces the system cost.The closed-loop system avoids manual adjustment of phase error in traditional testing process.In the algorithm,In-system amplitude and phase calibration method is proposed to initial path signal well.On this basis,combined with Monte Carlo iteration algorithm,the error function of maximizing signal-to-noise ratio is optimized according to the large number theorem,so that the array antenna can satisfy the main lobe beam pointing requirement as much as possible,while effectively suppressing the interference direction.The hardware architecture designed and fabricated in this paper validates the effectiveness of the above two algorithms in the test environment.The system can achieve the task requirements of path self-calibration and beamforming-nulling.The experimental results show that the simulated beamforming architecture is a mature solution and has broad market prospects and research value in the radar communication.