###### Abstract  
The deployable reflector antenna based on the synthetic aperture radar is a satellite component that consists of a unit structure in the form of a folded reflector. During the launch process, this satellite antenna is in the stowed condition to improve storage efficiency. It is then deployed to perform the space mission in the on-orbit condition. Due to these structural characteristics of the deployable reflector antenna, the reflector is possible to be loaded in the limited volume of the launch vehicle with the reduced size. Additionally, because the deployable reflector antenna is made by the lightweight material of the carbon fiber reinforced polymer and honeycomb core, it can reduce the launching cost and improve the revisit interval. In this paper, the conceptual design of the main reflector of the deployable reflector antenna was conducted. The main reflector was designed as the honeycomb sandwich composite structure. To design the main reflector, the stacking sequence of the composite material and honeycomb core was investigated to maximize the structural stiffness and minimize the antenna's mass. Subsequently, finite element analyses including modal, quasi-static, structural-thermal coupling, and transient response were performed to numerically evaluate the structural performance of the lightweight composite reflector antenna. ynthetic aperture radar (SAR); deployable reflector antenna (DR-A); honeycomb sandwich composite structure; carbon fiber reinforcement polymer (CFRP); finite element analysis +
Footnote †: journal: Applied  
0000-0001-5900-0001-5900-00001-5900-0001-5900-0001-59000-0001-5900-0001-59000-0001-59000  
among the DR-As. Thus, the design of the main reflector is a key component for improving the performance of the antenna system. Lightweight deployable antenna improves the revisit cycle time for fast satellite operation and facilitates cost reduction for the launch process. The main reflector should be designed to reduce weight while maintaining structural stiffness [8; 9; 10]. Several works are implemented to design the deployable reflector in the satellite antenna [11]. In order to improve the volume ratio between the deployed and stowed conditions, a mesh-type reflector was developed [12]. Due to the flexibility of the reflecting surface, the satellite equipped with mesh-type antenna is possible to transfer into the on-orbit environment with a limited volume of launch vehicle fairing. But a mesh-type reflecting surface has the bigger shape error than the solid-type antenna. In order to enhance the dynamic stiffness of the solid-type main reflector, the stiffener is applied to thin the CFRP composite reflector. While the CFRP reflective surface to which the stiffener is applied has high dynamic stiffness in the global vibrating mode, the local vibration in the area without the stiffener is large, which reduces the performance of the antenna in terms of attitude control. In this paper, the main reflector with the honeycomb sandwich composite structure was developed to satisfy the design requirements including size, weight, and structural stiffness. In the design approach, the design variables are the material properties and the laminated stacking sequence of the composite material. Finally, the structural stability of the DR-A developed in this paper is numerically demonstrated using structural analyses of structural mode, quasi-static, thermal gradient, and dynamic behavior. In this paper, the CFRP honeycomb sandwich structure consists of the CFRP material of YSH70A [13] which is space-grade composite material with high strength and the aramid honeycomb core of ECK 4.8 [14]. Also, the shape of the main reflector is axisymmetric Cassegrain type consisting of the main- and sub-reflectors (Table 1). In Section 2, the overall design approach is presented. Section 3 shows the sequential design process of the main reflector consisting of the stacking sequence of carbon fiber-reinforced polymer (CFRP) and the spatial distribution of the honeycomb core.