| With the rapid development of the global communication industry,wireless communication technology as the main means of communication has gradually been widely concerned by scholars at home and abroad,and antenna as an important part of the whole wireless communication system.Its performance plays an important role in the accuracy and real time of communication.However,for the antenna working on the ground or in space,the surface distortion may occur due to gravity effect or temperature change,which leads to the structural accuracy and electrical performance reduced greatly.Aiming at this situation,an electromechanical coupling optimization compensation method is proposed to improve the electrical performance of deformed reflector antenna by using actuators to adjust structural deformation and Physical Optics(PO)method to calculate electrical performance.The specific contents of this study are listed as follows:Firstly,based on the plate deformation theory,the relationship between the displacement of each node and the adjustable nodes in the deformation plane is established.The deformation of the panel can be changed by applying different displacements at the adjustable points.At the same time,the process of solving the far field electrical performance of a single reflector by the PO method is derived.In view of the problem that the mesh accuracy affects the accuracy of the calculation,the Gaussian integral method is used instead of the trapezoidal integral.The structural grid is converted to electromagnetic grid for electrical performance calculation.Then,a single reflector antenna with a diameter of 2.2 meters is taken as an example.The finite element model of reflector antenna is established in finite element analysis software.The far field electric field value of antenna is obtained by using the PO method.The results are compared with the results of electromagnetic analysis software.The accuracy of formula derivation is verified.Then,the adjustment method based on plate deformation theory is used to compensate the single reflector antenna under the condition of gravity.The far field pattern before and after compensation is obtained by using the PO method.The results show that the surface accuracy and electrical performance of the antenna can be improved by adjusting the displacement at the nodes of the reflector properly.Next,based on the PO method of the single reflector,the PO/PO method of the dual reflector is derived.The subreflector and support structures are established on the basis of the main reflector surface model,which is established in the previous chapter.And the Gregorian reflector antenna is formed.PO/PO method is used to calculate the far field electric field of the dual reflector antenna without applied load,and the accuracy of the derivation is proved by comparing with GRASP.At the same time,the deformation cloud map and the far-field pattern of the antenna with random error are analyzed.According to the relationship between structural accuracy and electrical performance of reflector antennas,the electromechanical coupling optimization model with the objective of electrical performance is established,and the Particle Swarm Optimization(PSO)is selected to solve the modal.By optimizing the adjustments of the actuators installed on the main and subreflector,the deformation on the main surface is offset by the deformation on the subreflector,so as to improve the electrical performance of the antenna.And the effectiveness of the compensation method is verified according to the simulation results.Finally,according to the surface accuracy and electrical performance of the antenna in space environment are reduced due to thermal deformation caused by temperature load.Taking a space deployable antenna with a diameter of 5 meters as an example,the finite element model is established.Within the range of the temperature variation in space,different temperature loads are applied to the antenna.The variation of electrical performance and surface accuracy is analyzed and the worst working condition is determined,the antenna is compensated based on the worst working condition.Then,four different electrical performance parameters are used as the optimization objectives,and the electromechanical coupling optimization model is established,the PSO algorithm is used to optimize the actuators adjustments.The results show that this method can effectively improve the electrical performance of the deformed reflector antenna. |
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