Numerical and Experimental Studies on Frequency Characteristics of hbox TE 11 -Mode Enhanced Coaxial Vircator

• Published in: IEEE transactions on plasma science Vol. 39; no. 9; pp. 1762 - 1767
• Main Authors: Zhang, Yongpeng, Liu, Guozhi, Shao, Hao, Liang, Tiezhu, Zhang, Ligang, Teng, Yan, Yan, Lixin, Lin, Yuzheng
• Format: Journal Article
• Language: English
• Published: 01.09.2011
• Subjects: Anode effect; Diodes; Electric potential; Electron beams; Emittance; Microwaves; Particle in cell technique; Voltage
• ISSN: 0093-3813; 1939-9375
• DOI: 10.1109/TPS.2011.2161618

Due to azimuthal-asymmetric electron emitting, hbox TE 11 -mode output of high-power microwave is unavoidable in coaxial vircator. In order to obtain a pure mode output, hbox TE 11 -mode enhanced design by opposed section electron emitting is applied. As 2-D effect along azimuthal direction is introduced, the frequency of microwave generated is shifted in hbox TE 11 -mode enhanced coaxial vircator, compared with the thoroughly coaxial one. Frequency characteristics of hbox TE 11 -mode enhanced coaxial vircator are numerically and experimentally studied by the 3-D particle-in-cell code UNIPIC. Simulation results show that a stable hbox TE 11 -mode output is generated nearly with a point frequency in the S-band by hbox TE 11 -mode-enhanced geometry, which is a little lower than that in the thoroughly coaxial geometry. In experiments, nearly point frequency and stable hbox TE 11 -mode output is also obtained, and the effects of diode voltage, anode-cathode gap, and electron beams width are investigated. The results show that with higher diode voltage, smaller anode-cathode gap, and larger electron beam width, the microwave frequency is higher, particularly that the electron beam width has an equal effect with the diode voltage and the anode-cathode gap, which agree well with the simulation results. Meanwhile, microwave generation was obtained with steady power above 800 MW at about 5% efficiency in the experiments.