Research On Source Reconstruction Theory Based On Time Reversal Algorithm

Due to its good temporal and spatial focusing characteristics,time reversal technology has become one of the research hotspots in the fields of detection target positioning,target imaging,wireless communication,etc.It has great research value in solving the inverse problem in the propagation of electromagnetic waves and realizing the application of source reconstruction of excitation sources.Based on the temporal and spatial focusing characteristics of time reversal technology,this paper explores a series of practical improved algorithms,and applies them to the phased array failure diagnosis and electromagnetic interference source location based on source reconstruction to obtain better application effects.The specific research content is divided into the following four parts:First of all,based on the digital signal processing method,this paper theoretically derives the temporal and spatial focusing characteristics of time reversal.The numerical results confirm the existence of temporal and spatial focusing phenomena,and verify the validity of the derived conclusions.At the same time,frequency domain analysis based on time reversal shows that any form of signal source has temporal and spatial focusing characteristics,and it shows that the bandwidth and form of the signal are important factors that affect the focusing effect of source reconstruction.Secondly,an improved algorithm to improve the accuracy of radiation source reconstruction is proposed.The algorithm uses the spatial sparsity of the source,not only can improve the reconstruction accuracy of multiple discrete pulse excitation sources,but also can effectively improve the reconstruction accuracy of the aggregated source.In addition,to solve the problem that the above-mentioned improved algorithm cannot realize the reconstruction of the excitation source at non-zero time,this paper introduces the minimum entropy algorithm to improve the above algorithm to realize the accurate reconstruction of the excitation source at any time.Then,in order to solve the problem that the algorithm mentioned above cannot realize the reconstruction of continuous pulse excitation source,this paper proposes a source reconstruction algorithm that performs spatial positioning and then time positioning to expand the application range of radiation source reconstruction methods based on time reversal technology.The algorithm uses clustering algorithm to classify the spatial points according to the focus characteristics of time reversal,so as to obtain the position information of the source point.And then uses the maximum peak criterion to find the focus moment of the reconstructed source,reproduces the field distribution of all the spatial points at that moment,and finally realize the source reconstruction.In order to verify the effectiveness of the above algorithm,this paper carried out source reconstruction experiments and electromagnetic interference source location experiments on the rectangular wave signal source.Finally,in order to make up for the problem that the previous algorithm cannot efficiently locate the time-shifted failed elements in the phased array antenna,this paper proposes a source reconstruction algorithm based on frequency domain deconvolution.This algorithm can achieve accurate positioning of failed signal sources while ensuring higher positioning efficiency and lower time cost.The article verifies the effectiveness of the algorithm through an application example in the field of phased array antenna detection.In addition,considering that the time reversal cavity wall in practical engineering applications is a lossy conductive material,which will have a certain impact on the reconstruction accuracy,this paper studies a method of placing a metal plate on the time reversal cavity wall to improve the accuracy of source reconstruction.