A G-Band Traveling Wave Tube With 20 W Continuous Wave Output Power

The development of a G-band traveling wave tube for wireless communications and airborne radars is described. The maximum output power of this device is over 20 W. This device provides a saturation output power over 15 W and a saturation gain over 32 dB with a bandwidth of 7.6 GHz. A folded waveguide circuit with modified circular bends is utilized to eliminate the band-edge instability caused by the high beam voltage of 20 kV. A pencil beam of 50 mA with a transmission ratio over 95 % is realized, making the device capable of operating in continuous wave mode. Periodic permanent magnets are employed for compactness. Chemical vapor deposition diamond disc is used in the input and output RF windows to minimize the loss and voltage standing wave ratios of the traveling wave tube. The weight and the size of the device are 2 kg and 300 mm x 70 mm x 70 mm, respectively. The efficiency of the device is over 5 %.