The Study Of Novel Integrated Traveling Wave Tube

With the competition of the solid traveling wave tube(TWT) and the demand of the Terahertz frequency application, the vacuum TWTs are required to increase the frequency continually. However, the complex and fine struce of the triditional TWTs limited the output power, which ask for arising novel slow wave structure(SWS) and newfangled architecture. While one of the efficient ways to extend the output power is that the TWT spatial integrated or cascade connection. With the development of the modern processing technic also, such as novel large-current-density cathode emitter, LIGA and DRIE technic et al, it become possible to integrate the vacuum tubes.This doctoral dissertation describles the key technologies for TWT integration, following five novel points:1. The basic theory of the mult-beam integrated electronic optical system(EOS) is present, which include steady Maxwell equation, momentum equation with Relativity and the current continuity equation. The theory of axisymmetric structure is put forward firstly and then we promote the Non-axisymmetric theory for the mult-beam integrated EOS.2. The general beam wave interaction(BWI) model is presented and the effect of the BWI in the paralel and cascade integration of the SWS is analyzed. In order to solve the BWI in the various new SWS, we study the general field of the structure and deverate the formula of the linear BWI, and then establish the large signal theory model of the BWI. And then the BWI in the two typical integration, spatial parallet or cascade connection, are discussed and set up a mult-beam wave interaction model. Also the input power limitation is studied in the cascade TWT.3. The key technology of EOS of the mult-beam integration of the TWT is put forward. The sheet beam bunching by uniform magnetic field, Wiggler field, PCM field are compared first. Then the sheet beam spatial integration is designed carefully. Finally high efficiency of mult-beam depress collction is also simulated.4. This dissertation gives the study of the plane cascade TWT which have great advantage for integration manufacture and to acheive higher output power. The key point is to overcome the reflection of the connection between to sub-structure. So, different connection has been analized and a novel E plane angle-cut waveguide is put forward, which can obtain better performance but compress the size of the structure.5. The design method for heterostructure cascade TWT is promoted. The heterostructure cascade TWT can synthesize different SWS characteristic into the cascade TWT. In order to balance the limitation of each TWT and obtain better combination performance, a design method is present first, and then a V band helix-FWG cascade TWT is carefully designed. The simulations predict that a peak power of 800 W with saturated gain of 55 dB from 55 GHz to 60 GHz(5 GHz bandwidth) can be achieved.