Reducing the Attenuation in CFRP Waveguide Using Carbon Fiber Veil

Carbon fiber reinforced polymer (CFRP) materials are anisotropic lossy conductors which restrict their use in high-performance lightweight and load-bearing waveguides. The attenuation of CFRP waveguides has been improved in this research by investigating and comparing three different manufacturing techniques. WR-90 waveguides have been manufactured from Cytec IM7/977-3 prepreg and their transmission performance was evaluated. Three different techniques were implemented to reduce waveguide losses including: copper foil lining, conductive paint, and a new integrated metalized carbon fiber veil (CFV) material. The new lightweight high conductivity CFV was integrated into the walls of a CFRP waveguide which reduced the per unit length attenuation to below 1 dB/m. This was an improvement of up to 5.5 dB over raw carbon fiber and similar to the performance of a copper foil-lined waveguide.