Design of the large-size high-precision reflector of the spacecraft antenna with the planimetric directional diagram

Exploration of high frequency range of onboard antenna system and growing of SC on-board repeater power allow receiving and transmitting lots of information data and organizing high quality channels of fixed satellite communication. A reflector is a key antenna element. Pointing accuracy depends on precision and dimension stability of reflector, subjected during operation to the influence of such negative factors as extreme positive and negative temperatures (taking into account their gradient), vacuum and radiation. Also, the increasing of spacecraft capacity and gain ratio in given coverage area can be provided by increasing of reflector aperture area with specially graded reflecting surface, forming contoured antenna pattern. Strict requirements to the shape precision of the reflecting surface of the reflector and strict antenna weight restrictions suggest the usage of structural material, having extremely low thermal expansion ratio, high specific strength and stiffness properties, low density, resistance to continuous static and dynamic loads, vibration resistance, operation feasibility under high and low temperature conditions. The results of a new large-size offset SC antenna reflector design, forming contoured antenna pattern, made of composite materials are presented in the paper. The structure is realized according to the “superlight” reflector scheme and consists of two main elements: reflector and primary structure. It allowed decreasing reflector mass by 30 % in comparison to standard construction. Moreover, the given reflector has temperature and mechanical decoupling of structural components. The paper includes complex algorithm of the large-sized antenna reflector design. The rationale is presented relating to the choice of design-layout scheme and used materials. The problem of determining reflector locking device positions on the SC according to vibration frequency value is solved. Mechanical analysis and optimization of design parameters of reflector construction are carried out. The results can be interesting to wide range of specialists: to design engineers, engineers and material engineers.