Research On CLEAN Technology Base On Antenna Array

In order to reduce the complexity of array antenna design and signal processing,random Sparse array antenna are widely used today,but there are also problems such as high side-lobes and uncertain side-lobe positions.In particular,the improvement of the peak side lobes will greatly plague the subsequent processing of the array signals.In this thesis,the"optimized array"technique needs to ensure the high-precision position error of the array element for reducing side lobes.So the CLEAN algorithm is used to remove the side lobes.Focusing on the improvement of the traditional CLEAN algorithm,this thesis mainly does the following research:1.The pattern and sidelobe characteristics of the one-dimensional uniform array antenna and the high sidelobe problem caused by the random array antenna are analyzed.Then,the main lobe position,width and side lobe information of the planar rectangular grid array antenna pattern are derived and summarized.Finally,the influence factors of the main lobe gain and the sidelobe dynamic range in the random array theory are analyzed.The object to be improved in this thesis is studied:the ratio of the Average side lobes and the mean side lobes.2.Calculate B_p by obtaining the pattern from the position of the element to improve the CLEAN calculation.The feasibility of this improved method is proved by the matlab simulation of CLEAN algorithm based on one-dimensional array antenna.Then the detailed implementation process of CLEAN algorithm based on rectangular grid array antenna is derived,and the specific mathematical model formula is given.The block diagram of the improved CLEAN algorithm is given,and the related matlab simulation is completed.3.Using statistical methods,it is analyzed that the improvedB_p is smaller and closer to the actual value than the traditional method when the position error of the array element is not very large.Compared with the conservative estimation of the threshold in the traditional algorithm,the threshold value in the improved CLEAN algorithm is more accurate.The improved CLEAN algorithm has better image quality improvement under poor imaging conditions.It is proved that the improved CLEAN algorithm can handle more targets when the position error of the array element is not large and the array elements are the same.Finally,the convergence of CLEAN algorithm and the improvement of image quality are analyzed.4.Finally,the improved CLEAN algorithm is used to process the measured signals of the two-dimensional array antenna.