Design Study of GW-THz Wave Transmission Without Mode Competition in an Oversized Relativistic Backward Wave Oscillator

Min, Sun-Hong; Kwon, Ohjoon; Sattorov, Matlabjon; Jung, H.; Baek, In‐Keun; Bera, Anirban; Barik, R. K.; Bhattacharya, Ranajoy; Park, Gun-Sik

doi:10.1109/tps.2017.2665523

Cited by 14 publications

(10 citation statements)

References 42 publications

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“…As the operating frequency extends to millimeter-wave and terahertz bands, the power capability reduces as the size of the interaction circuits shrinks [4]. Therefore, in order to obtain sufficient power capability and high output power, operating in high-order mode is proposed and attempted in a large number of research works [5][6][7][8][9][10][11][12]. For example, the TM 01 mode is commonly employed for BWOs [7], the TE 0n mode or higher-order TE mn mode is adopted for gyrotrons [8], and the TE n1 mode is usually utilized for the relativistic magnetrons [9].…”

Section: Introductionmentioning

confidence: 99%

A Compact Circular Waveguide Directional Coupler for High-Order Mode Vacuum Electronic Devices

Zhu,

Fu,

et al. 2024

Electronics

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In this paper, a compact circular waveguide directional coupler for high-order mode vacuum electronic devices is presented and investigated. To reduce the size, the primary and secondary waveguides of this coupler are connected in an orthogonal way by two coupling holes. Moreover, to improve the directivity and operating bandwidth, a method of loading adjustable metal stubs on the isolating port is proposed and introduced in design. A Ka-band TE01-mode circular waveguide directional coupler was designed, and the structure parameters were optimized by electromagnetic simulation. To verify the design, a prototype sample was fabricated, assembled, and tested. The experimental results show good agreement with the simulations, and the directivity are improved by adjusting the metal stubs on the isolating port. In the experiment, a 26.7 dB directivity at 35 GHz was obtained, and the bandwidth of directivity above 20 dB was higher than 7 GHz, corresponding to a relative bandwidth higher than 20%. Meanwhile, the TE01° mode maintained good transmission efficiency in this compact high-order mode directional coupler.

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Section: Introductionmentioning

confidence: 99%

A Compact Circular Waveguide Directional Coupler for High-Order Mode Vacuum Electronic Devices

Zhu,

Fu,

et al. 2024

Electronics

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“…Cerenkov oscillator is also believed potential in the millimeter wave range [9], [10]. By enlarging the device's transverse section area, the power capacity is much improved, which is quite meaningful and essential in advancing the performance of millimeter-wave generators [11]- [15]. J. Zhu has developed a Cerenkov oscillator with an overmoded ratio (α) as high as 4.5 [16].…”

Section: Introductionmentioning

confidence: 99%

Influence of SWS Size on Mode Purification in an Overmoded Ka-Band Cerenkov Oscillator

Teng

Wang

et al. 2020

IEEE Access

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Overmoded slow-wave structure (SWS) plays an important role in developing the performance of Cerenkov oscillators at the millimeter-wave range. To investigate the effect of SWS size on power capacity as well as the problem of mode competition, the properties of the resonance modes in an overmoded SWS are focused on. Based on the mode selection method of enhancing the field of TM 01 and keeping the field of TM 02 mode steady, the output results for SWSs with various sizes are studied. Consequently, the size of SWS is reasonably determined, which can provide an effective beam-wave interaction process and the purified output mode. Moreover, the study on electron's movement in the diode area under the magnetic field of 0.8 T is conducted and then the value of the overmoded ratio α is finally confirmed as 2.5 to guarantee a lossless transportation of the electron beam. Verified by the particle-in-cell (PIC) simulations, the optimized structure shows a good capability of improving the output power and purifying the output mode.

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“…In South Korea, Min et al . designed the 0.1–0.5 THz oversized BWO by using 500 kV–5 kA electron beam 34 . To pursue high electron current and small circuit thermal deposition, even CPI Inc. has been considering adopting this kind of configuration to inprove the performance of high frequency extended interaction klystron (EIK) 10 .…”

Section: Introductionmentioning

confidence: 99%

“…Currently, most experiments on the high power slow wave devices in the terahertz range are conducted in the frequency range below 200 GHz, above which many research works are conducting, but most of them are still at the stages of theoretical designs and numerical simulations 34 . In this work, a compact oversized SWO driven by the annular relativistic electron beam is proposed and experimented with operation frequency in the Y-band.…”

Section: Introductionmentioning

confidence: 99%

A megawatt-level surface wave oscillator in Y-band with large oversized structure driven by annular relativistic electron beam

Wang

et al. 2018

Sci Rep

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High power vacuum electronic devices of millimeter wave to terahertz regime are attracting extensive interests due to their potential applications in science and technologies. In this paper, the design and experimental results of a powerful compact oversized surface wave oscillator (SWO) in Y-band are presented. The cylindrical slow wave structure (SWS) with rectangular corrugations and large diameter about 6.8 times the radiation wavelength is proposed to support the surface wave interacting with annular relativistic electron beam. By choosing appropriate beam parameters, the beam-wave interaction takes place near the π-point of TM01 mode dispersion curve, giving high coupling impedance and temporal growth rate compared with higher TM0n modes. The fundamental mode operation of the device is verified by the particle-in-cell (PIC) simulation results, which also indicate its capability of tens of megawatts power output in the Y-band. Finally, a compact experimental setup is completed to validate our design. Measurement results show that a terahertz pulse with frequency in the range of 0.319–0.349 THz, duration of about 2 ns and radiation power of about 2.1 MW has been generated.

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Design Study of GW-THz Wave Transmission Without Mode Competition in an Oversized Relativistic Backward Wave Oscillator

Cited by 14 publications

References 42 publications

A Compact Circular Waveguide Directional Coupler for High-Order Mode Vacuum Electronic Devices

A Compact Circular Waveguide Directional Coupler for High-Order Mode Vacuum Electronic Devices

Influence of SWS Size on Mode Purification in an Overmoded Ka-Band Cerenkov Oscillator

A megawatt-level surface wave oscillator in Y-band with large oversized structure driven by annular relativistic electron beam

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