# Structural Optimization Design of Spaceborne Microwave Probe Antenna
## 5 Conclusions  
This paper mainly introduces the optimization design method of the reinforcement of the scanning drive mechanism of the star-carried microwave probe antenna. The antenna scanning drive mechanism has two motion modes, uniform speed and variable speed, and the structural form of the reflecting surface leads to a large perturbation moment in the two scanning modes, which affects the high-precision attitude positioning of the satellite. In order to solve this problem, this article proposes an integrated design method that combines topology optimization and size optimization to reconstruct the layout and size of the reinforcement ribs, obtaining the following conclusions:  
1. The topology optimization takes the maximum structural dynamic stiffness as the optimization objective, and a more reasonable lightweight antenna reflective surface backing rib structure can be obtained. 2. On the basis of topology optimization, size optimization is carried out. The size optimization takes the minimum rotational moment of inertia as the optimization objective to reduce the influence of moment disturbance. The mass of the reinforcing bar after the size optimization is 155.9 g, which is 26% less than the original structure. The rotational inertia is reduced by 39% compared to the original structure. The perturbation moment in uniform rotation is reduced by 52%, and in variable-speed motion, the perturbation moment is reduced by 39% compared to the original structure. All of these are below the 0.05 N requirement for the spaceborne microwave probe antenna. These reductions significantly enhance the system's performance in high-precision satellite operations, reducing disturbances and improving accuracy. 3. The combination of topology optimization and size optimization can lead to a structure with better mechanical properties, which can be extended to the structure optimization design of all kinds of antennas. The topology optimization ensures the dynamic stiffness of the structure, and the size optimization reduces the rotational inertia of the structure and helps to improve the motion control precision and stability of the system, which is suitable for scenarios that require high-precision rotation. It is conducive to the realization of the high-stability attitude control of satellites. This integrated method offers a more systematic approach to optimizing both performance and mass, moving beyond traditional engineering experience-based approaches. Comparing the first- through fifth-order vibration modes of the original structure and the new structure, it is evident that the first three modes primarily involve vibrations on the front side of the rotating shaft. The dynamic stiffness of the new structure on the front side of the rotating shaft is superior to that of the original structure, resulting in higher frequencies for the new structure in the first three modes. Starting from the fourth mode, the higher-order vibration modes are localized at the edges. The ribs of the original structure are predominantly distributed at the edges with a broader coverage, whereas the ribs of the new structure are concentrated around the rotation axis. The dynamic stiffness of the new structure, following topology optimization, is greater than that of the original structure, with reduced rotational inertia and lower reinforcement mass. The reinforcement of the new structure is positioned near the center of the rotating axis, and the reinforcement layout of the original structure, which encircles the antenna along the plane, is not the optimal configuration. Conceptualization, D.W. and W.F. ; methodology, D.W. and W.F. ; software, D.W., C.Y. and P.K. ; validation, D.W. and W.F. ; formal analysis, D.W.; investigation, D.W. and C.Y. ; resources, J.H. and S.Z. ; data curation, D.W. and P.K. ; writing--original draft preparation, D.W.; writing--review and editing, W.F. and P.K. ; visualization, D.W.; supervision, W.F. ; project administration, J.H. and S.Z. ; funding acquisition, W.F.