Photonic Crystal Waveguide Twt Research Load Twists And Turns

Traveling wave tube(TWT) is an important military electronic equipment. Higher order mode oscillation is one of the reasons that cause TWT unstable.The stability of TWT can be enhanced if the operation mode of TWT is within photonic band gaps(PBG),and the competitive mode of TWT is within photonic passing bands when photonic crystals are to replace the metal shield tube of slow wave structure,for photonic crystals have the capability of wave filtering.This thesis studies TWTs shielded by photonic crystals to improve the output stability based on the above principle.The study includes the transmission behavior of the electromagnetic wave in finite two-dimensional photonic crystals; the dispersion characteristics,the Pierce interaction impedance,transmission characteristics of slow wave circuit shielded by photonic crystals in Ku band;the selectivity of PhC to electromagnetic wave in the SWS;and the beam-wave interaction of Ku-band folded-waveguide(FW) slow-wave structure(SWS) shielded by Photonic crystals(PhC).Chapter1is the introduction.In chapter1,both the development of TWTs and PhC are presented;the researches of TWTs shielded by PhC are reviewed.In chapter2,the transmission characteristics of rectangular waveguide loaded by PhC and the transmission characteristics of rectangular waveguide shielded by the metal are studied and compared.In chapter3, the dispersion characteristics,the Pierce interaction impedance of Ku-band FW SWS shielded by PhC are discussed,and the comparison is proceeded between the Ku-band FW SWS shielded by PhC and shielded by metal having the same dimension; at last,transmission characteristics of SWC shielded by PhCs is simulated.In chapter4, the design process of the input and output matchers of the SWS shielded by PhCs is explained, and the fabrication model of the matchers is presented.In chapter5,the beam-wave interaction of Ku-band FW SWS TWT shielded by PhC is studied. The results demonstrate that the electromagnetic signals in the SWS shielded by PhC can be amplified effectively.The results of the study explain that the TWT shielded by PhCs can filter out the higher order mode in SWS after reasonable designs,and it is possible to improve the stability of the TWT by introducing PhCs into it.