Multi-Field-Coupled Model And Solution Of Active Phased Array Antenna Based On Model Reconstruction

Active phased array antenna(APAA)is an antenna that uses the electronic scanning technique to direct the antenna beam rotating or scanning in space.It has the characteristics of high reliability,good detection capability,and great stealth performance.Therefor it has great application potential in radar systems of various new weapon platforms such as missile,airborne,satellite borne,shipboard,vehicle and aerostat.With the development of APAA towards high-frequency bands and high-density arrays,the thermal-structuralelectromagnetic coupling becomes increasingly significant.It causes gain loss,sidelobe elevation,and reduced pointing accuracy,thus restricting the development of high-performance array antenna.However,for the coupling problem of APAA,the previously reported theoretical modeling only considers the deformation of the antenna array affected by the coupling field,and ignores the effect of the deformation of feed system.Moreover,the solution for APAA multi-field coupling has the problem of data model heterogeneity and mesh mismatching between different physical fields.As a result,the accuracy of coupling analysis is reduced.In this paper,for the above problems of APAA multi-field coupling,a multi-field coupling modeling and numerical solution method of APAA based on model reconstruction is proposed.Firstly,the deformation error of feed system in the coupling field is introduced into the existing theoretical model,and the field-circuit coupling model including feed system of APAA is established.The electrical performance of antenna is expressed as the functional of structural parameters of antenna array and feed system,and the coupling mechanism of APAA is revealed.Secondly,based on the feature of multi-physics sequence coupling of APAA,a model reconstruction method between coupling fields is proposed,which includes the NURBS(Non-Uniform Rational B-Spline)surface fitting algorithm that guarantees the accuracy of both the position and shape of array elements,and the local model reconstruction algorithm that ensures the accuracy of both the amplitude and phase of feed connectors.And based on this method,the numerical solution of APAA multi-field coupling is realized,which improves the accuracy and efficiency of the coupling analysis.Finally,the method is applied to the numerical solution for the 5.8 GHz 32-unit APAA multi-field coupling problem.And the mechanical experiment and electrical experiment are carried out.The numerical solution results are compared with the experimental results: the relative error of gain is 2.24%,the relative error of beam direction is 2.17%,and the relative error of sidelobe is less than 8.71%,which verifies the accuracy and effectiveness of the proposed method.Compared with the traditional method,the analysis accuracy of the proposed method is improved by an average of 56.19%,and the analysis speed is improved by an average of 55.14%.