The increasing demand of high data rate is posing a high pressure to actual mobile networks. Fiber and wireless networks cover most of the populations, but there are many regions uncovered by a satisfactory service. The distribution of internet by satellite communications is already available at microwave frequency. The request of multigigabit data rate needs a wide bandwidth that only millimeter waves can provide. The band 71 – 86 GHz offers two sub bands of 5 GHz each suitable for satellite communications. However, due to the high atmosphere attenuation, an adequate transmission power has to be provided. The preliminary design of a 71 – 76 GHz Traveling Wave Tube based on the Double Corrugated Waveguide, for millimeter wave satellite communications is reported.