A high-efficiency L-band coaxial three-period relativistic Cherenkov oscillator

Xing-Jun Ge,Jun Zhang,Si-Yao Chen,Zhi-Cheng Luo,Chen-Yu Zhao,Peng Zhang,Han-Wu Yang

doi:10.1038/s41598-019-47496-8

Xing-Jun Ge, Jun Zhang + Show 5 more

Open Access

https://doi.org/10.1038/s41598-019-47496-8

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Journal: Scientific Reports	Publication Date: Aug 22, 2019
Citations: 5	License type: open-access

Affiliation: National University of Defense Technology

Abstract

Miniaturization is one of the important research directions of low frequency high power microwave sources. This paper presents a three-period coaxial slow-wave structure L-band high-power microwave source. Because the coaxial Quasi-TEM mode has no cut-off frequency, the radial size of the device can be reduced. At the same time, in order to reduce the transverse dimension, the coaxial extractor structure is introduced to realize the longitudinal mode selection and improve the conversion efficiency of the device. In simulation, the device obtains the microwave output with the central frequency of 1.53 GHz, the average power of 3.3 GW and the efficiency of 40%. By optimizing the scheme of electron beam collection, the phenomenon of pulse shortening is effectively suppressed. In the experiment, the device obtains the microwave output with the central frequency of 1.52 GHz, the average power of 3 GW, the efficiency of 33% and the pulse width of 40 ns.

Highlights

High power microwave (HPM) source, as a research hotspot of relativistic vacuum electronic devices, has made great progress in the past decades[1,2,3,4,5]
The following focuses on the functions of the coaxial SWSs and the coaxial extractor
The TORCH-01 accelerator is capable of providing an electrical power up to 10 GW with a full width at half maximum (FWHM) pulse duration of about 55 ns

Summary

Device Design and Physical Analysis

The beam-wave interactions occur primarily in the coaxial SWSs region where electrons are fully bunched and transfer energy to the electromagnetic field. The output microwave spectrum is relatively pure with a central frequency of 1.53 GHz, which effectively inhibits frequency doubling and high-order mode In other word, it shows the good propagation of the electron beam and the effective interaction between the electron and the electromagnetic field. The measured pattern of microwave radiation (as shown in Fig. 12) agrees well with the theoretical mode of the symmetric TM01 mode, indicating that the dominant mode of the device is the quasi-TEM mode

Conclusion

Author Contributions

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