Terahertz Broadband High-Gain EIK

Terahertz radiation sources play a crucial role in the advancement of terahertz technology and hold significant value in their study.The Extended-Interaction Klystron(EIK)combines the benefits of Traveling Wave Tube(TWT)and Klystron,exhibiting high-gain and wide bandwidth,making it the focus of research on terahertz radiation sources.In this thesis,a Hughes structure loaded with a sub-wavelength hole array is proposed as a high-frequency structure,and a broadband high-gain EIK working in terahertz band is designed.Specific work is as follows:1.The high-frequency properties of the Hughes structure cavity coupled with the sub-wavelength hole array were studied through theoretical analysis and simulation.The electric field distribution of single-period structures was examined and the impact of structural parameter changes on dispersion and coupling characteristics was analyzed.The structural parameters and working modes were identified.2.The cold cavity characteristics of the Hughes structure cavity and the Hughes structure cavity coupled with the loaded sub-wavelength hole array were compared.A six-gap model was constructed for both structures with a resonant frequency of 0.23 THz.The latter showed a 29.6% improvement in characteristic impedance compared to the former.The input and output cavities were designed respectively and the input and output cavities composed of the Hughes structure cavity coupled with the loaded sub-wavelength hole array showed less reflection in a wider frequency range.3.The Hughes structure EIK was studied through particle simulation.The Hughes structure cavity was used as the high-frequency structure in a five-cavity six-gap EIK.Working parameters were determined and the center frequency was identified through particle simulation of the input cavity.The analysis was conducted on the impact caused by the inconsistency between the input signal frequency and the resonant frequency of the middle cavity.Using stagger tuning,the optimized output performance of the Hughes structure EIK was obtained.When the Direct Current(DC)voltage of the electron beam is 13.2kV and the DC current is 0.3A,and the input signal power is20 mW with a frequency of 231.2GHz,the output power is 94 W,corresponding to a gain of 36.7dB and a 3dB bandwidth of 1.06 GHz.4.The Hughes structure EIK loaded with the sub-wavelength hole array was studied through particle simulation.The basic working parameters were determined and the bandwidth was expanded through stagging-tuning.The four-cavity,five-cavity,and six-cavity EIKs were studied through particle simulation,with the five-cavity EIK performing best.The impact of working parameters such as electron beam DC voltage,DC current,input signal power,and frequency on the EIK output performance is analyzed,and the optimized results are obtained.When the DC voltage of the electron beam is 13.2kV and the DC current is 0.3A,and the input signal power is 20 mW with a frequency of 231.3GHz,the output power is 152 W,corresponding to a gain of 38.8dB and a 3dB bandwidth of 1.28 GHz.5.The study of particle simulation of the Hughes structure EIK loaded with sub-wavelength hole array and Hughes structure EIK shows that the former increases output power by 61.7% and bandwidth by 20.7% under the same operating conditions,exhibiting better advantages in terms of gain and bandwidth.This study provides insight into further research on high-performance EIK in the terahertz waveband.