Microfabrication methods for W-band TWT circuits

Fabrication of slow-wave circuits for TWTs is challenging at frequencies in the upper millimeter-wave range, due to size and geometry limitations of available methods. We describe fabrication techniques being developed for mmW circuits based on microfabrication and additive manufacturing. We present progress on W-band serpentine waveguide circuits fabricated by UV-LIGA, 3D printing, and CNC machining.