A method for fabricating a filament-affixed trace within an electronic device, such as a circuit board or microelectronic device. Conductive traces are affixed to the surface of a composite substrate containing filaments in a matrix bonded to an underlying solid material. The matrix is then removed, leaving the conductive traces suspended or supported by filaments. The signal intensity attenuation for filament-suspended or filament-supported signal lines is much lower than signal lines embedded in solid dielectric materials, allowing for transmission of significantly higher frequency signals within filament-suspended and filament-supported signal lines.