Phased Array Beamforming Based On Subarray Division And Its Application

In order to solve the complex nonlinear problem of phased array antenna beamforming,intelligent optimization algorithm and adaptive algorithm are widely used in this field.The intelligence algorithm has excellent solving ability and robustness.They can solve some arrays problems which are strictly constrained.The adaptive beamforming algorithms have great flexibility and they can control beam pointing flexibly.At the same time,they can also enhance the expected signal and suppress the interference signal.My work includes beam forming of phased array antenna,which is as follows:1.The large number of array elements for phased array antennas result in the increase of calculations of total adaptive beamforming and the increase of cost.A division method of antenna array based on the ant colony algorithm and symmetric division is proposed.And it can search interval points of array.Then,the antenna array is divided into multiple sub-arrays.Finally,compared with the uniform division method,the proposed algorithm has lower side lobe level.2.In this thesis,based on the conventional algorithm for MVDR(Minimum Variance Distortion Response),the adaptive diagonal loading technique is introduced.The adaptive beamforming algorithm for ADL-MVDR at sub-array level is proposed.Simulation results show that under the conditions of medium SNR and low SNR,this algorithm reduces the sidelobe level of the pattern.It is a better beamforming algorithm based on sub-array.3.In this thesis,for the shared aperture antenna array,a new optimum method of shared aperture beamforming based on the Wind Driven Optimization(WDO)is proposed.Firstly,the space constraint of each array element is designed and the peak side lobe level(PSLL)of the two sub-array patterns is used as objective function.Then,according to the constraint formula,the initial coordinates of sub-array 1 and sub-array 2 array elements are developed successively.These two sub-array elements positions are optimized by using the WDO method to reduce PSLL of the beamforming and fulfill the design of shared aperture antenna array working at the different frequency.Finally,this proposed algorithm has better feasibility and effectiveness in the shared aperture beamforming.Compared with the particle swarm optimization algorithm and the traditional SMI algorithm,the width of the main lobe is narrower and the sidelobe level is lower in this proposed algorithm.4.Based on the online shared aperture array antenna,the algorithm of circular shared aperture beamforming is designed.According to the signal model,signal orientation function and the beamforming objective function are established.Under the premise of meeting the constraints of the element spacing,the wind driven algorithm is used to optimize the location of the two sub arrays,so that the maximum sidelobe level is further reduced.Aiming at the multi beam forming technology of the shared aperture staggered subarray,the beam allocation algorithm of multi beam in the ship data chain is studied.The formation detection algorithm of a shape such as triangle and rectangle is designed.Under the premise that each phased array has 4 array surfaces and each array can generate 2 beams.The beam selection of various node arrays is completed in the current time slot.