Article
Engineering, Electrical & Electronic
Xiaoqing Zhang, Jinjun Feng, Jun Cai, Yinghua Du, Ruitong Dong, Xianping Wu
Summary: The study introduces a modified folded waveguide structure to enhance the power output of W-band traveling-wave tubes, utilizing phase velocity tapering technology and high beam current to achieve higher output power and electronic efficiency.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2021)
Article
Engineering, Electrical & Electronic
Jinjing Luo, Jin Xu, Pengcheng Yin, Jian Zhang, Dongdong Jia, Wuyang Fan, Yue Ouyang, Lingna Yue, Jinchi Cai, Hairong Yin, Gangxiong Wu, Zhanliang Wang, Yubin Gong, Yanyu Wei
Summary: The article introduces a novel slow wave structure (SWS) called sine-shaped FWG (S-FWG) as a promising choice for a high-power amplifier. By transforming the arc-shaped segment of the traditional FWG into a sinusoidal waveguide, the proposed SWS can be optimized quickly and produce a greater interaction impedance, leading to higher output power compared to the traditional FWG SWS.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Engineering, Electrical & Electronic
Yuan Feng, Pan Pan, Changqing Zhang, Hanwen Tian, Jinjun Feng
Summary: This study explores the design method for ultrawideband amplification with low-gain fluctuation in the terahertz folded-waveguide traveling-wave tube (TWT). Due to sharply reduced interaction impedance, effective amplification with a flat gain characteristic can only be achieved in a limited range in the folded-waveguide circuit. The use of an oversized beam tunnel in the design of a terahertz TWT further worsens the situation. By modifying the geometry of the circuit based on careful analysis of the folded-waveguide design characteristics, the interaction impedance is increased by 26% over a wide operation frequency band, enabling the use of phase velocity tapering technology to increase efficiency and balance the gain. A design example in G-band demonstrates the capability of the interaction circuit to produce 18-W output power over 30 GHz from 202 to 232 GHz with a gain fluctuation of less than 1.5 dB.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Engineering, Electrical & Electronic
Yuan Zheng, Shasha Qiu, Blake Griffin, Rich Kowalczyk, N. C. Luhmann Jr, Diana Gamzina
Summary: This article presents the design of a compact and efficient folded waveguide traveling wave tube (TWT) for high-speed data communications in the E-band frequency range. Various innovative techniques, including a rectangular beam tunnel, a novel focusing system, and a multi-stage coupler, have been employed to enhance the performance of the TWT. The simulations and experimental results show that the designed TWT can achieve a high power output, low variation, low distortion, and high efficiency over the target frequency band.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Engineering, Electrical & Electronic
Ruifeng Zhang, Mengzhen Li, Zugen Guo, Feng Lan, Yubin Gong, Zhaoyun Duan, Fei Xiao, Huarong Gong
Summary: This article proposes a novel technique called 3-stage gain equalization technique (GET) to address the gain fluctuation and bandwidth limitation in folded-waveguide traveling-wave tubes (FWG-TWTs). The GET improves gain at high frequency and decreases gain at low frequency to achieve gain equalization and extend bandwidth. Compared with traditional TWTs, the 3-stage FWG-TWT achieves significant improvement in gain flatness and bandwidth.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Article
Engineering, Electrical & Electronic
Han Lai, Ruifeng Zhang, Zugen Guo, Feng Lan, Jiezhong Luo, Zhaoyun Duan, Yubin Gong, Fei Xiao, Huarong Gong
Summary: This article presents a novel 1-D active transmission matrix-based time-dependent (ATM-TD) model for the beam-wave interaction analysis of folded-waveguide (FWG) traveling-wave tubes (TWTs). The proposed model accurately depicts the real-time interactions between the electron beam and the electromagnetic wave in FWG TWTs. It enables the performance analysis of devices driven by multisignal and complex digital modulation signals, thus facilitating the design of FWG TWT.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Computer Science, Information Systems
Kexin Ma, Jun Cai, Jinjun Feng
Summary: This research focused on miniaturizing E-band traveling-wave tubes by optimizing the cosine-vane folded waveguide slow-wave structure and introducing a novel miniaturized T-shaped coupler to achieve good performance in low voltage conditions. Simulation results showed high gain and saturated output power, indicating significant advantages for future wireless communication applications.
Article
Engineering, Electrical & Electronic
Yanyan Tian, Guoxiang Shu, Yubin Gong, Huabi Yin, Wenlong He
Summary: In this article, a folded waveguide with two coupling grooves is proposed for high-power and high-frequency traveling wave tubes (TWTs). The structure allows a modified TE $_{\text{20}}$ high-order mode to interact with two sheet electron beams. The transmission characteristics of this novel structure were simulated and measured. A good $\textit{S}_{\text{21}}$ of $-$10 dB and $\textit{S}_{\text{11}}$ of less than $-$15 dB were achieved in the 218-230-GHz range. Moreover, simulations of the beam-wave interaction in this structure predicted an output power of 930 W at 220 GHz, with a small signal gain of 58 dB and a 3-dB bandwidth of 1.3 GHz.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Engineering, Electrical & Electronic
Yongtao Li, Hanyan Li, Zhenglin Li, Jinjun Feng, Fengyi Liao, Shaoming Pan, Xuefeng Mai
Summary: In this study, W-band FWG circuits were produced using UV-LIGA technology with high dimensional accuracy. The dimension error had no obvious effect on the S12-parameters within the operating bandwidth range.
MICROELECTRONIC ENGINEERING
(2021)
Article
Engineering, Electrical & Electronic
Feng Lan, Zugen Guo, Ruifeng Zhang, Han Lai, Jiezhong Luo, Zhaoyun Duan, Yubin Gong, Fei Xiao, Gil Travish, Huarong Gong
Summary: In this article, deep reinforcement learning (DRL) is used to explore high-performance folded-waveguide (FWG) slow-wave structures (SWSs) for broadband application in traveling-wave tubes (TWTs). By combining deep learning (DL) and reinforcement learning (RL), DRL forms a complete automated system for designing FWG SWSs. The simulation results show that this method can effectively design well-structured FWG SWSs in the frequency band centered at 850 GHz.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Physics, Fluids & Plasmas
Yijun Zhu, Yang Xie, Hehong Fan, Changsheng Shen, Zhaofu Chen, Ningfeng Bai, Xiaohan Sun
Summary: This article presents a bidirectional fully connected deep neural network (BFC-DNN) for practical design of folded waveguide slow wave structures (SWSs) in multiple frequency bands. The BFC-DNN is trained using exact numerical simulation results in a supervised learning manner, and demonstrates high performance in different frequency bands.
IEEE TRANSACTIONS ON PLASMA SCIENCE
(2022)
Article
Physics, Fluids & Plasmas
Vishant Gahlaut, A. Mercy Latha, R. K. Sharma, S. K. Ghosh
Summary: This research designed a corrugated single-stage collector with high efficiency for folded waveguide traveling wave tubes (FW-TWT), which improved collector efficiency by about 6% compared to traditional collectors by self-trapping secondary electrons and increasing surface area. The study found that combining forced air cooling, axial grooves, and radiator fins can effectively reduce collector temperature.
IEEE TRANSACTIONS ON PLASMA SCIENCE
(2021)
Article
Engineering, Electrical & Electronic
Jinjing Luo, Jin Xu, Pengcheng Yin, Jian Zhang, Dongdong Jia, Jinchi Cai, Linna Yue, Hairong Yin, Zhanliang Wang, Yanyu Wei
Summary: This study proposes a modified slotted sine waveguide slow wave structure (MS-SWG SWS) as a potential construction in the terahertz region, which has the advantages of being simple to fabricate and low transmission loss. Cold-test results demonstrate the feasibility of the processing scheme, with the S11 <- 15 dB ranging from 330 to 390 GHz. Particle-in-cell (PIC) simulation reveals that the MS-SWG SWS can generate an output power of 17.4 W at 340 GHz with a gain of 33.9 dB and a 3-dB bandwidth of 11 GHz from 334 to 345 GHz. The simulation findings also show a flow rate of 100% for the matched electron-optical system (EOS) consisting of an electron gun, a periodic permanent magnet (PPM), and a single-stage depressed collector.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Engineering, Electrical & Electronic
Kwang-Ho Jang, Jong-Hyun Kim, Geun-Ju Kim, Jung-Il Kim, Jin-Joo Choi
Summary: This study demonstrated the feasibility of using a sub-terahertz (THz) traveling-wave tube (TWT) by measuring transmission characteristics and TWT performance through X-ray LIGA micro-fabrication process applied to the interaction circuit. The E-bend folded waveguide, a simple lithography-friendly structure, was used as the circuit type. The W-band circuit was chosen for TWT application and showed accurate manufacturing and desired nonlinear characteristics.
JOURNAL OF ELECTROMAGNETIC ENGINEERING AND SCIENCE
(2023)
Article
Nanoscience & Nanotechnology
Fengying Lu, Ke Li, Zhixiong Lei, Ming Huang, Wensheng Qiao
Summary: This paper presents a novel sheet beam folded waveguide slow-wave structure for enhanced output power of oscillators in the millimeter wave to terahertz regime. Through particle-in-cell simulation results, it is demonstrated that the SB FWO exhibits better performance than conventional circular beam FWO. The voltage and frequency tuning performance of the SB FWO, as well as clutter suppression, were discussed, and a preliminary experiment was conducted to measure the S parameter of a 220 GHz SB FWG-SWS.
