Continuous-wave Y-band planar BWO with wide tunable bandwidth

Xi, Hongzhu; Wang, Jianguo; He, Zhaochang; Zhu, Gang; Wang, Yue; Wang, Hao; Chen, Zaigao; Li, Rong; Liu, Luwei

doi:10.1038/s41598-017-18740-w

Cited by 36 publications

(14 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To speed up the start time of the terahertz signal, we may inject the external small terahertz signal 61 with our newly developed continuous-wave Y-band planar BWO 25 .…”

Section: Particle Simulation Resultsmentioning

confidence: 99%

Relativistic Surface Wave Oscillator in Y-Band with Large Oversized Structures Modulated by Dual Reflectors

Wang

2020

Sci Rep

Self Cite

View full text Add to dashboard Cite

To increase the generation efficiency of the terahertz wave in the Y band, the idea of dual-reflector is introduced in the relativistic surface wave oscillator (SWo) with large oversized structures. the dual-reflector and the slow-wave structure (SWS) construct a resonator where the field strength of tM 01 mode inside is intensively enhanced and then the efficiency is increased. The pre-modulation on electron beam caused by the reflector is also helpful in improving the output power. Meanwhile, the reflector can reduce the loss of negatively going electrons. Through the particle-in-cell (PIC) simulations, the optimized structure is tested to be stable and little power is transmitting back to the diode area. The output power reaches 138 MW in the perfectly electrical conductivity condition and the frequency is 337.7 GHz with a pure spectrum. The device's efficiency is increased from 10.7% to 16.2%, compared with the device without any reflectors. The performance of device with lossy material is also focused on. In the situation of copper device, the output power is about 41 MW under the same input conditions and the corresponding efficiency is about 4.8%. In recent years, the terahertz wave has shown great potential in the applications of remote high-resolution imaging, remote detection of radioactive material, deep space research and communications, plasma diagnostic in nuclear fusion, materials research, biomedical diagnostics, high data rate communications, basic biological spectroscopy, chemical spectroscopy, and so on 1-8. The prospect of terahertz technology has attracted many researchers to devote to developing the high power terahertz generators, especially the vacuum electronic devices (VEDs) 9-13. And the slow wave devices are an important class of the VEDs. Based on the interaction between the intense electron beam and the slow-wave structure (SWS), the backward wave oscillator (BWO) becomes a remarkable kind of slow wave device with good performance in high output power and compact structure 14,15. In a BWO, the electrons are in synchronism with −1 st spatial harmonic wave. When a slow wave device operates near the upper edge of the transmission band, it becomes a surface wave oscillator (SWO) whose operation point is close to π point. In an SWO, the fundamental wave slows down to the electron velocity 16. The Q-factor in the SWO is relatively large due to the large reflection and small group velocity, and then the start current is usually lowered in this case 17,18. What's more, the large coupling impedance in the SWO is significant in obtaining high interaction efficiency. Besides, use of the surface wave is valid in achieving mode selection in the overmoded structure as well. Thus, the SWO attracts more and more attention in generating millimeter and terahertz waves. However, their structural dimensions decrease rapidly as the working frequency goes up, causing many crucial problems that must be solved, such as the internal breakdown, limitation of the power capacity, and difficulties in manufacturi...

show abstract

“…To speed up the start time of the terahertz signal, we may inject the external small terahertz signal 61 with our newly developed continuous-wave Y-band planar BWO 25 .…”

Section: Particle Simulation Resultsmentioning

confidence: 99%

Relativistic Surface Wave Oscillator in Y-Band with Large Oversized Structures Modulated by Dual Reflectors

Wang

2020

Sci Rep

Self Cite

View full text Add to dashboard Cite

show abstract

“…There is a phase difference with 180 • between the left part and middle part of the electric fields of the TE x30 mode in the x-y cross section, and the phase of the left part is the same as the phase of the right part. The distributions of the electric fields of the TE x20 mode in the x-y cross section are antisymmetric, and it is difficult to excite the antisymmetric mode by three symmetrically distributed electron beams [17,26]. Therefore, the TE x20 mode could not be excited.…”

Section: Analysis Of the Mode Competitionmentioning

confidence: 99%

Simulation Study of a High-Order Mode Bwo With Multiple Inclined Rectangular Electron Beams

Wang¹,

Zhang²,

Gao³

2021

PIER C

View full text Add to dashboard Cite

A backward wave oscillator (BWO) operating at the high-order mode (HOM) with multiple inclined rectangular electron beams (IRBs) is presented in this article. The BWO operating at the HOM with multiple IRBs (HOM IRB BWO) is driven by multiple IRBs. Compared with typical BWOs, the slow wave structure of the HOM IRB BWO is an overmoded metal-grating rectangular waveguide (OGRWG). The mode competition of the slow-wave device operating at the HOM is analyzed according to the ohmic losses of different modes of the OGRWG slow wave structure and multiple beams exciting. The analysis is verified by simulation. Two kinds of HOM-fundamental mode converters (MCs) are designed for converting the HOM generated by the HOM IRB BWO into the fundamental mode. The beam-wave interaction of the HOM IRB BWOs with the HOM-fundamental MC is studied. The results show that the mode competition does not occur; frequency spectrums of output signals are pure; and the HOM is converted into the fundamental mode effectively.

show abstract

“…As the core component of THz TWT, the slow-wave structure (SWS) directly determines the device performance of this high power terahertz radiation source. Nowadays, many kinds of slow wave structures including folded waveguide [8][9] , corrugated rectangular waveguide (CRWG) [10][11] , double corrugated rectangular waveguide (DCRWG) [12] , staggered double-gate structure [13][14] and so on, have been proposed to develop high power radiation source in terahertz band. However, with the increase of operating frequency, the large transmission loss and strong re ection of these slow-wave structures limit the output power and bandwidth of THz TWT.…”

Section: Introductionmentioning

confidence: 99%

A Piecewise Sine Waveguide for Terahertz Traveling Wave Tube

Zhang

Jiang

Lei

et al. 2022

Preprint

View full text Add to dashboard Cite

In this paper, a piecewise sine waveguide (PWSWG) is proposed as the slow-wave structure (SWS) to develop high power terahertz travelling wave tube (TWT). The PWSWG evolves from a rectangular waveguide oscillating with the piecewise sine curve along its longitudinal direction. Through the analysis of slow wave characteristics and transmission properties, it can be found that the PWSWG SWS has the advantages of high interaction impedance and excellent electromagnetic transmission performance. Furthermore, the calculation results of beam-wave interaction show that the TWT based on PWSWG SWS can generate the radiated power of 251W at the typical frequency of 220GHz, corresponding to a gain of 37.01dB and an interaction efficiency of 6.8%. Compared with the conventional sine waveguide (SWG) TWTs, the PWSWG TWT has higher interaction efficiency and shorter saturation tube length. In conclusion, the PWSWG will be considered as the potential SWS for high power terahertz radiation sources.

show abstract

Continuous-wave Y-band planar BWO with wide tunable bandwidth

Cited by 36 publications

References 32 publications

Relativistic Surface Wave Oscillator in Y-Band with Large Oversized Structures Modulated by Dual Reflectors

Relativistic Surface Wave Oscillator in Y-Band with Large Oversized Structures Modulated by Dual Reflectors

Simulation Study of a High-Order Mode Bwo With Multiple Inclined Rectangular Electron Beams

A Piecewise Sine Waveguide for Terahertz Traveling Wave Tube

Contact Info

Product

Resources

About