Investigation of an Axial Virtual Cathode Oscillator with an Open-Ended Coaxial Cathode

Autor: Se-Hoon Kim, Chang-Jin Lee, Wan-Il Kim, Kwang-Cheol Ko
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: Journal of Electromagnetic Engineering and Science, Vol 22, Iss 3, Pp 265-271 (2022)
Druh dokumentu: article
ISSN: 2671-7255
2671-7263
DOI: 10.26866/jees.2022.3.r.86
Popis: A cathode with an open-ended coaxial structure is experimentally investigated using an axial virtual cathode oscillator (vircator). To enhance the microwave power output, an open-ended coaxial cathode is installed in the axial vircator. The proposed cathode is designed based on the reciprocating frequency of the vircator. The operation features of an axial vircator with a solid cathode, an annular cathode, and an open-ended coaxial cathode are comparatively analyzed through simulations and experiments. Three cathodes are machined using graphite. A stainless steel mesh with a transparency of 70% is used as an anode. The anode-to-cathode gap is fixed to 6 mm. The vircator is driven using a 10-stage PFN-Marx generator with a characteristic impedance of 31 Ω. The PFN-Marx generator applies −150 kV voltage pulses with a 170–200 ns pulse width into the vircator. The microwave power from the solid and annular cathodes is 11.22 MW and 11.27 MW, respectively. The proposed cathode generates a microwave with a power of 12.65 MW while enhancing the microwave power by 13% compared with the solid and annular cathodes. The proposed cathode shows a frequency shift to 3.4 GHz, which is a much lower frequency than that of the solid cathode at 6.34 GHz.
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