Research On Transmitting And Receiving Beamforming Based On FDA

Beamforming technology is one of the most important branch of modern array signal processing, research based on phased array beamforming technology is already quite mature. frequency diverse array(FDA) can offer range-dependent beam and scan the whole space automatically, which make frequency diverse array suitable for a lot of potential scenarios, such as range-related transmitting energy control, range-dependent interference suppression and target detection and localization, all these applications are based on frequency diverse array beamforming theory. Based on the projects ‘Research on frequency diverse array’ and ‘Frequency Diverse Array-based Wireless Communication Principle and Applications’, this thesis mainly focuses on the study of beamforming technology based on frequency diverse array.The main work and innovation embodied in the following four aspects:1. The beamforming method of phased array and the beampattern characteristic of frequency diverse array are studied in depth. As an extension of the phased array,frequency diverse array can learn from a phased array beamforming method to establish its own beamforming theory. Firstly, the conventional beamforming method and adaptive beamforming method are studied, then the influence of key design parameters on the beampattern of frequency diverse array is discussed, which lay the foundation for the research of frequency diverse array beamforming technology.2. A method for dot-shaped range-angle transmit beampattern is proposed. The range and angle are coupled for beampattern of traditional frequency diverse array, that is to say, the angle of spacial beam is determined for a certain range, vice versa. This characteristic is undesirable for precise spacial beam controlling and can cause some difficulties to the application. The proposed method solve this problem by forming a dot-shaped range-angle beam in target location.The relevant signal model is derived and the computer simulation is carried out, results show that this method has better energy focusing effect and spatial resolution.3. Combining the difference between frequency diverse array and phased array steering vector, the minimum variance distortionless response(MVDR) beamforming method for frequency diverse array is presented, simulation results show that this method can further suppress interference to improve signal to interference plus noiseratio(SINR).4. A beamforming method for frequency diverse array using particle swarm optimization algorithm(PSO) is proposed. With the output signal to interference plus noise ratio as the fitness function, the optimal array weight vector is obtained.Compared with the conventional beamforming method, this method can effectively suppress the interference in range and angle dimension, thus improving the SINR.