Study On The Deformation Analysis And Compensation Of Conformal Array Antennas

Compared with the traditional liner array or planar array,conformal array antennas need to be attached to the conformal carriers.When vibration and deformation occurs on the conformal carrier in practical applications,the performance of the conformal arraywill be greatly affected and some common DOA estimation algorithms and beamforming algorithms are no longer applicable.In order to guarantee the conformal antenna can work normally,it is necessary to thoroughly understand the deformation effect of the conformal array,analyze the variation of the conformal array parameters and the estimation error of the DOA estimation algorithm when the array is deformed.Furthermore,feasible schemes should be employed to compensate for the deformation error of the array.Firstly,the modeling principle of the conformal array with deformation is described.When the conformal array is deformed,the array elements are irregularly arranged,which is more complicated than the traditional conformal array antenna for modeling.And the deformation of the wing conformal antenna is simulated and the influence of vibration deformation on the wing conformal antenna is analyzed.At the same time,the robustness of different DOA estimation algorithms applied in deformed conformal array are analyzed,making preparation for subsequent calibration work.Secondly,the traditional amplitude and phase error correction algorithms are introduced and simulated.The error caused by the array deformation can not be corrected directly using the traditional error correction algorithm,which has the characteristics of azimuth dependence.In this thesis,an error correction algorithm based on improved ESPRIT algorithm is proposed to deal with the amplitude and phase errors caused by the low order deformation of the array.This algorithm has the characteristics of ESPRIT algorithm without spectral search.To calibrate the DOAs estimation in other directions,a approximation model is established for the low order deformation of the array with the aid of the correction source.Then,combined with the vibration model,a compensation method is proposed to compensate the deformation error by using the amplitude error of the deformed antenna.The method does not need auxiliary correction source,and it uses shape fit as an optimization factor.Accuracy requirements is achieved by iterative convergence.Simulation results show that the proposed method can accurately reproduce the deformation shape of the array and effectively compensate the position error caused by wing vibration.The method has the advantages of fast convergence and good stability.Finally,full wave simulation of the deformed conformal array antenna is carried out by using HFSS.The influences of the deformation on the antenna parameters,i.e.frequency,radiation pattern,of the array element are studied,and the changes of the parameters such as the pattern and gain of the array after deformation of the array are analyzed.The principle and effect of phase compensation for the element position error are introduced.