Test of Ka-Band High-Power Folded Waveguide Traveling Wave Tube

In order to develop high-power folded waveguide traveling wave tubes, increasing the voltage is one way. However, with a fixed bandwidth, the traditional folded waveguide has insufficient phase velocity and cannot increase output power by raising voltage. In this paper, a new folded waveguide is proposed. By shortening the length of the straight waveguide, the phase velocity can be effectively enhanced. With the increase of phase velocity, the applied working voltage can also be increased accordingly. Based on the new structure, a folded waveguide traveling wave tube was designed and processed for testing. Within the operating bandwidth of 33–37 GHz and under the working conditions of 43.7 kV voltage and 3.4 A current, relevant measurements were carried out. The results indicate that the output power is 4 kW with a peak power of 7.1 kW, and the gain exceeds 35 dB. The feasibility of the new structure in high-power traveling wave tubes has been successfully verified.