Research On Electromechanical Coupling Modeling Of Patch Arrays Considering Element Deformation

With the increase in the amount of data transmitted in modern communication,higher requirements are put forward for the comprehensive performance of antennas such as multifrequency bands and high gain.Among all kinds of antennas,patch antenna(PA),as one of its important components,has developed rapidly in the past 50 years.PA is favored by researchers due to its many advantages such as light weight,small size,low cost,and easy fabrication.It has great potential and is widely used in arrays.However,with the increase of working environment and usage time,the shape of the array antenna may be difficult to maintain,resulting in poor electrical performance and even difficult to work properly.In the past,the transmission line theoretical model was used to analyze the radiation performance of the PA itself in the deformed PA array,but the influence of the insufficient accuracy of the transmission line theoretical model on the far-field radiation analysis of the PA was not considered.In this thesis,an equivalent surface magnetic current analysis method is proposed from the perspective of improving the far-region radiation analysis method of the PA unit.On this basis,the influence of the array element deformation on the radiation field in the far area of the PA is studied.Finally,an electromechanical coupling model of the PA array antenna is established by taking the bending deformation of the PA array antenna in the length direction of the PA as an example.The details are as follows:(1)Aiming at the shortcomings of the existing transmission line theoretical analysis of the PA far-field radiation field,the influence of the three initial design parameters of the PA on the accuracy of the transmission line model is firstly analyzed.It is determined that the main factor affecting the E-plane pattern of the transmission line model is the relative permittivity of the dielectric material.According to the specific influence mechanism of the relative permittivity on the transmission line model,the surface magnetic current distance D is optimized to obtain the optimal equivalent surface magnetic current distance.Then the equivalent coefficient,equivalent dielectric constant and the functional relationship between equivalent coefficient and relative dielectric constant are obtained.Finally,an equivalent surface magnetic current analysis method for analyzing the far-field radiation of PA is obtained.(2)According to the structural characteristics of the PA itself,the errors in actual manufacturing and the different conditions of use,the deformation of the array element is divided into two cases: linear error in the thickness of dielectric substrate and bending deformation of PA as a whole.The former can be further divided into errors in the length direction of the patch and errors in the width direction of the patch.The latter overall deformation can be further subdivided into bending deformation along the width direction of the patch and bending deformation along the length direction.The far field of the deformed array element is equivalently analyzed by the proposed equivalent surface magnetic current analysis method.And the electromechanical coupling model of a single array element is established.The simulation case is compared with the calculation results to verify the accuracy of the coupled model.(3)According to the existing array antenna theory,the electromechanical coupling relationship caused by the deformation of the array antenna is analyzed,which may lead to the change of the position of the array element,the change of the attitude and the deformation of the array element itself.Then,combined with the bending deformation of the PA unit along the length direction in the above analysis,the corresponding electromechanical coupling model of the PA array antenna is established.According to the obtained coupling model,the electrical performance of the deformed PA array antenna can be analyzed.Finally,four deformation situations are analyzed by taking the 9×2 array as an example.The accuracy is verified by comparing the coupling model with the HFSS simulation results.