The Research Of Novel Coupled-cavity Slow-wave Structure For X-band Traveling-wave Tube

Traveling-wave tube(TWT)is the most widely used vacuum electronic device and it can combine high power and wide band effectively,which makes it widely used in military and civil fields.According to the different slow-wave structures,traveling wave tube can be roughly divided into helix TWT and coupled-cavity traveling-wave tube(CC-TWT).Due to the bad heat dissipation,helix TWT power is limited and because of the all metal structure,CC-TWT can obtain high power since it has better heat dissipation than helix TWT.The all-metal slow-wave structures have advantage in heat dissipation,so that the power capacity is large.However,the metal sealing would enhance the dispersion and make bandwidth become narrow,so it need to find a good balance between the two.Therefore,it is significant to explore the novel coupled-cavity slow-wave structure that has high power and wide bandwidth.In this paper,we mainly study novel coupled-cavity slow-wave structure for X-Band Traveling-Wave Tube.On the one hand,we optimize high power X-band CC-TWT with a novel ridge-loaded staggered single-slot rectangular slow wave structure.On the other hand,we design an X-band reentrant double-staggered ladder coupled-cavity structure TWT.The main content of this paper are listed as follows:1.The coupled-cavity slow-wave structure field theory is analyzed by using perturbation theory and the high frequency characteristics of slow-wave structure are also studied.2.In the condition of keeping high interaction impedance as much as possible and decreasing normalized phase velocity appropriately,the high frequency characteristics of ridge-loaded staggered single-slot rectangular slow-wave structure are optimized and the periods of slow-wave structure are jumping change.The simulation results shows that it can produces output power over 20 kW and its gain over 37 dB when the beam current is set to 5A and the beam voltage is set to 25.2 kV across the bandwidth of 8.3-9.8GHz.Meanwhile,its electronic efficiency is up to 17 percent at the 8.6-9.5 GHz frequency range.3.A reentrant double-staggered ladder coupled-cavity structure for X-band TWT is designed and the size of each part of the coupled-cavity that affects the high frequency characteristics is studied.Then the input and output ports,which includes transition waveguides and several severs are designed and optimized.Simulation results shows that it can produces output power over 20.8 kW and its gain over 37.2 dB when the beam current is set to 5A and the beam voltage is set to 25.9 kV across the bandwidth of 8.6-9.9GHz and its electronic efficiency is up to 16 percent around the frequency range from 8.6 to 9.9GHz.