A Method of Metallisation of Carbon Fibre-Reinforced Plastic (CFRP) Sandwich Antenna Reflector Dish for High-Frequency Applications

CFRP sandwich structures have proved themselves as a good candidate for satellite antenna reflectors due to high bending stiffness with lower mass. Bare CFRP acts as a reflector for frequencies up to Ku-band beyond which reflective properties are insufficient. Studies are carried out by researchers to improve the reflectivity of CFRP sandwich structures and one of the widely adopted methods is metallisation of the reflective surface of CFRP. Glass transition temperature (Tg) of CFRP is much below the melting point of metals, which makes the process of metalising more challenging. This is overcome by a few approaches such as chemical vapour deposition, sputtering, and cold spray. In the present study, a unique concept of metalising the CFRP sandwich dish by co-curing it with copper-cladded polyimide film is presented. To facilitate the bond between CFRP and copper-cladded polyimide film, the resin available in CFRP prepreg itself is used during the co-curing process. The procedure was successfully adopted in a high-throughput satellite payload of ISRO missions.