Terahertz Extended Interaction Klystron Theory And Simulation

The extended interaction klystron(EIK)is a linear electric injection vacuum device developed from the improvement of the traditional klystron.Its structure combines the characteristics of the klystron and the TWT.As people's communication frequency bands continue to move toward higher frequency bands,research and development above the W band and even the terahertz band are constantly being carried out,and the research and development of electric vacuum devices which supporting the terahertz wave is also imminent.At this stage,EIK must have advantages in output power and gain in W-band and lower frequency bands.Traditional klystron amplifiers and traveling wave tube amplifiers have advantages in output power and gain.There is no obvious advantage,so how to let EIK continue to maintain its advantages in these higher frequency bands is a problem that needs to be solved urgently at this stage.This paper aims to explore how EIK can maintain the advantages of high power and high efficiency compared with traditional klystrons and TWT in the terahertz frequency band.The main content starts with the introduction of terahertz technology and the current extended interaction devices.,Explained the theory and working principle of the traditional klystron and the extended interaction device,and explained in detail the simultaneous process of velocity modulation and electron clustering in the extended interaction resonator.At this stage,there is no clear determinism on how to "expand" in the extended interaction high-frequency structure.Therefore,this paper first tested four single-period extended interaction structures.By comparing the slow wave characteristics of each structure,two of them were selected.,Design and simulate two0.1THz EIKs,namely a double straight coupling slot structure EIK and a single meander coupling slot structure EIK,and analyze the single-period dispersion characteristics,coupling impedance characteristics and multi-period transmission loss characteristics of the two structures.On this basis,by simulating the interaction of their respective electron beams.Among them,the double straight coupling slot structure can achieve a peak output power of 6.2k W,a gain of 31.5d B,and an electron injection efficiency of 3.5%.The single zigzag coupling slot structure can achieve a peak output power of 4.8k W,a gain of 33.8d B,and an electron injection efficiency of 7%.Finally,the influence of electron beam voltage and electron beam current intensity on the output characteristics is analyzed.In order to explore how EIK can maintain the advantage of high power in the terahertz frequency band,based on the single tortuous coupling slot structure,by adjusting the structural parameters,a 0.3THz extended interaction klystron was designed and simulated,and its single-period dispersion characteristics were also analyzed.Coupling impedance characteristics and multi-cycle transmission loss characteristics,and carrying out the interaction simulation analysis after adding electron injection,can achieve a frequency of 305.8 GHz,a power of 2.3W,a gain of 20.6d B,and an electron injection efficiency of 2.1%.After simulating the above three EIKs,the advantages and disadvantages of the two extended interaction structures are compared,and the practicability of the tortuous coupling slot structure in the terahertz frequency band is discussed.Finally,due to actual work needs,this article finally conducts a simulation analysis on the Extended Interaction Oscillator(EIO),and analyzes the characteristics of its cold cavity and hot cavity.The EIO can achieve an average output power of 3.4kW.