Design and Microfabrication of a Double Corrugated Waveguide for G-band TWTs

A G-band (210 – 250 GHz) Traveling Wave Tube (TWT) is in the fabrication stage. The TWT specifications are gain in the range 25 - 35 dB with more than 1 W output power. The double corrugated waveguide is chosen as the slow wave structure for the relatively easy fabrication. The TWT is based on a single SWS section, instead of the typical configuration with two sections separated by a sever typical at microwave frequency. The short wavelength at G-band determines the size of the parts to be less than 100 microns. The design and the fabrication had to be harmonised to achieve a high precision fabrication. A high end Computer Numerically Controlled milling machine was used. The fabrication result confirms the capabilities of the fabrication process.