Study Of The Effect Of Mechanical Factors On The Electrical Performance Of Radomes

As a kind of typical electromechanical electronic equipments, the mechanical factors of radomes will affect the electrical performance of antenna-radome system. According to the problems of existent research on radomes, this thesis is mainly concerned with the effect of radome mechanical factors on the electrical performance. The author’s major contribution on the subject can be summarized as follows:1) The analysis model of the effect of radome mechanical factors on the electrical performance is constructed. The effect of radome structural deformation, material properties and radome thickness on the electrical performance is studied, and the analysis model of the effect of radome structural deformation, material properties and radome thickness on the electrical performance is constructed. On this basis, the effect of structural deformation of metal space frame radome on the electrical performance is analyzed, and the effect of material properties errors of streamlined airborne radome on the electrical performance is analyzed. Several conclusions are drawn from the simulation, which have reference value for practical engineering.2) Electromechanical integrated optimization of metal space frame radome is performed. Based on the analysis model of the effect of radome mechanical factors on the electrical performance, the concept of variable size members is introduced in the design of metal space frame radomes, and the electromechanical integrated optimization model is established, which is solved using the particle swarm optimization algorithm. The simulation results indicate that, through the integrated optimization, the electrical performance and the self-weight of the radome can be significantly improved without degrading the structural stiffness.3) A novel method based on reflector shaping is proposed to compensate the phase distortion of aperture field caused by dielectric sandwich radome. Dielectric sandwich radome degrades the electrical performance of the enclosed antenna by distorting the amplitude distribution and phase distribution of aperture field, of which the latter is mainly responsible for the distortion of far field pattern. Based on the analysis model of the effect of radome mechanical factors on the electrical performance, from the viewpoint of the integrated design of antenna-radome system, the effect of radome is considered in the antenna design phase, and the reflector antenna is shaped to compensate the phased distortion of antenna aperture field caused by the radome. The results of numerical experiments indicate that, the proposed method can effectively improve the electrical performance of the antenna-radome system, and the compensation effect on the sidelobe level and the null depth are especially significant.4) Multiobjective thickness profile optimization of airborne radome is performed. In the traditional thickness profile design of airborne radome, the radome design obtained by optimizing the boresight error will always have a relatively low transmission loss. Based on the analysis model of the effect of radome mechanical factors on the electrical performance, multiobjective particle swarm optimization of radome thickness profile is performed to improve simultaneously the boresight error and the transmission loss. The simulation results explain the aforementioned problem. Moreover, the "Transmission Loss Wall" phenomenon is found and explained. The obtained results are general for streamlined airborne radomes, and the conclusions can benefit the radome design in engineering applications.5) Inverse source reconstruction technique is employed to determine the material properties errors of semifinished radome. According to the problem of material properties errors affecting the electrical performance of airborne radome, employing the inverse source reconstruction technique, the inversion model between the transmission coefficients of the radome and the radiated far field is constructed using the high frequency method, and the method for determining the material properties from the transmission coefficients is proposed. The proposed method is relatively easy to implement, and decreases the dimension of the coefficient matrix in the inversion process. Furthermore, a mesh-refinement method, which does not increase the number of unknowns, is proposed to facilitate the far field measurement and the solving of the inversion model. Results of numerical experiments indicate that, using the proposed method to determine the material properties errors and correcting the radome thickness accordingly can effectively improve the electrical performance.