Research On Beamforming Method Of Sparse Array Antenna

In increasingly diverse fields such as mobile communication and military radar,array antennas have a wider range of applications than single antennas.Compared to uniform arrays,sparse arrays use fewer elements and have higher degrees of freedom in element distribution,which can effectively reduce costs,making them widely popular.In some applications of array antennas,specific directional patterns are desired to achieve specific functions,known as the beamforming problem of array antennas.Generally,the desired directional pattern can be formed by optimizing the array antenna element spacing,amplitude,phase,etc.,such as single-null,multi-null,and wide-null directional patterns.This thesis adopts the Self-Adaptive Differential Evolution algorithm(SaDE)to optimize linear and planar array antennas,respectively controlling their element spacing,amplitude,phase,and completing the beamforming of the specified directional pattern.The main work of the thesis is as follows:1.An introduction to the basic principles of array antennas was provided,along with a list of some fundamental indicators and parameters used to measure array antenna performance.The directional pattern functions of common array antennas were presented,and software simulations were performed to analyze them.2.This thesis describes the significance of studying beamforming for sparse array antennas,provides an overview of the current research status both domestically and internationally,and lists some common methods for beamforming research.3.This thesis studies the differential evolution algorithm and analyzes the improved algorithm,the adaptive differential evolution algorithm,discussing its basic principles,algorithm,and applicable scenarios as the main research method.For the corresponding array optimization model,a suitable fitness function is designed to study beamforming for linear array antennas and planar array antennas.By controlling the relevant parameters of the array through the algorithm,the array pattern is made to meet the specified shape.For a linear array,the spacing and amplitude of its elements are optimized and controlled,so that the array pattern either forms a null in a specified direction or forms a specific beam,such as a cosecant squared beam or a flat-topped beam.The main lobe width and sidelobe level of the array are also limited to a certain extent,and simulation experiments are conducted to verify the effectiveness of the algorithm in the field of beamforming for linear array antennas.4.The adaptive differential evolution algorithm is used to study beamforming of planar array antennas,optimizing the inter-element spacing of rectangular planar arrays of different sizes to produce nulls in specified directions while maintaining a certain level of sidelobe suppression.This verifies the effectiveness of the algorithm in the field of beamforming for planar array antennas.