Calibration Technique Of Phased Array Antenna With Mutual Coupling

As the continuous update and development of radar,navigation and satellite communication system,phased array antenna is widely used in various military and civil electronic equipments due to its high gain,multi-beam forming ability and fast scanning ability.However,the generation of induced current between the array will cause mutual coupling effect which seriously affect the precise pointing of the beam.Thus the tracking,identify and search ability of phased array radar will all reduce significantly.Therefore it is an important work to find an effective technology to improve the performance of phased array antenna with mutual coupling.In this paper,two methods of calibrating the beam pointing has been proposed and they has been verified by the simulated array.The major work is as following:Firstly,an array composed by broadband microstrip antennas which are fed by coupling structure is designed.The influence of the mutual coupling effect of the array on the radiation performance of the phased array antenna has been described in detail by analyzing the parameters of the antenna simulation and the deviation of the array beam pointing,which provides a reference for the verification of the following calibration methods.Then the element pattern reconstruction method which has been proposed is used to calibrate the beam pointing error of the phase array.This method uses a calibrated matrix to decrease the difference of the pattern of ideal array and the actual array,transforming the mutual coupling problem into the solution of the mutual coupling matrix.After beamforming the calibrated pattern,the actual angle is closer to the ideal angle.Finally,this paper introduces another method for beam pointing calibration.This method uses a calibration matrix to establish the weight of the actual array beam and the weight of the ideal array beam,converting the weight into a style without mutual coupling.It has been proved that the new method can nearly make the actual beam direction coincide with the expected beam direction.In addition,this method is simple to realize in engineering.