共查询到20条相似文献,搜索用时 62 毫秒
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J. Wu 《International Journal of Electronics》2013,100(11):661-672
In this paper, a new type of plasma-filled coaxial cylindrical dielectric slow-wave structure that is very beneficial to the beam-wave interaction of the high-power microwave source is developed. The Cherenkov radiation in the plasma-filled coaxial cylindrical dielectric slow-wave structure is examined by use of the self-consistent linear field theory. The dispersion equation and the synchronized condition as well as the wave growth rate of the beam-wave interaction are derived. The dispersion equation clearly shows that the Cherenkov radiation excited in the plasma-filled coaxial cylindrical dielectric slow-wave structure results from the coupling between the slow electromagnetic wave, TM-modes, propagated along the slow-wave structure and the negative-energy space-charge wave propagated along the relativistic electron beam. The numerical results indicate that the dispersion curves are divided into two branches due to the presence of the background plasma in the coaxial cylindrical dielectric slow-wave structure for the identical electromagnetic wave mode, and the radial distributions of the longitudinal fluctuating electric field corresponding to the two dispersion curve branches are completely different. Injection of the background plasma into the slow-wave structure can enhance the output frequency and the wave growth rate of the beam-wave interaction and enables the high-power microwave source that utilizes this kind of slow-wave structure to gain more output power of the microwave with higher output frequency. 相似文献
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Wu Jianqiang 《Journal of Infrared, Millimeter and Terahertz Waves》2003,24(12):2153-2162
Injection of background plasma into the beam-wave interaction region can greatly enhance the beam-wave interaction efficiency and the microwave output power of the device. In this paper, a new type of plasma-filled slow-wave structure, i.e., plasma-filled, dielectric-loaded coaxial cylindrical waveguide with a dielectric ring enclosing tightly the inner conductor, is developed. The Cherenkov radiation excited by the beam-wave interaction in the slow-wave structure is examined by use of the self-consistent linear field theory. The dispersion equation and the synchronized condition of the beam-wave interaction are derived. It's clearly shown that the Cherenkov radiation excited by the beam-wave interaction results from the coupling between the slow electromagnetic wave, TM-modes, propagated along the slow-wave structure and the negative-energy space-charge wave propagated along the relativistic electron beam. And the wave growth rate is solved, and the beam-wave energy exchange in the presence of the background plasma is discussed. Finally, the effects of the background plasma density on the dispersion characteristics, the distribution of the longitudinal fluctuating electric field, the wave growth rate and the beam-wave energy exchange are calculated and discussed. 相似文献
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M. V. Kartikeyan A. K. Sinha H. N. Bandopadhyay S. N. Joshi E. Borie M. Thumm 《Journal of Infrared, Millimeter and Terahertz Waves》2000,21(4):553-561
In this work, the field analysis of a cylindrical interaction structure, with helical grooves, and an inner dielectric lining for possible employment in high power TWT amplifiers in the conventional slow-wave regime, is presented. The Ohmic dominance of the microwave power on the walls of this propagating circuit is deduced. 相似文献
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We investigate a novel GaAs-based laser power converters (LPCs) grown by metal-organic chemical vapor deposition (MOCVD), which uses a single monolithic structure with six junctions connected by tunnel junctions to obtain a high output voltage. The LPCs with diameters of active aperture of 2 mm and 4 mm were fabricated and tested. The test results show that under an 808 nm laser, two LPCs both show an open circuit voltage of above 6.5 V. A maximum power conversion efficiency of 50.2% is obtained by 2 mm sample with laser power of 0.256 W, and an output electric power of 1.9 W with laser power of 4.85 W is obtained by 4 mm sample. The performances of the LPCs are deteriorated under illumination of high flux, and the 4 mm sample shows a higher laser power tolerance. 相似文献
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《Microwave Theory and Techniques》1987,35(12):1176-1182
Possible high-Q circuits based on a new crosstie overlay slow-wave structure are proposed for monolithic microwave integrated circuits. Configurations and results of slow-wave factors are presented. This structure is used for construction of a frequency-selective reflector with a compact size. The effect of loss is considered. 相似文献
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返波振荡器是一种重要的真空电子学太赫兹源,具有高功率、高工作频率和宽带调谐等特点。为提高圆形电子注与光栅慢波结构的互作用,提出一种双电子注嵌入矩形光栅的慢波结构,使电子注与光栅表面电场更好地充分相互作用,从而提高互作用效率和输出功率。通过数值求解和仿真计算其色散特性,结果表明,相比于相同结构参数的普通矩形单栅,该结构可以实现更高的工作频率和耦合阻抗。利用CST进行PIC仿真,优化结构和电子注参数,最终得到工作频率501 GHz,10.6 W的稳定输出。研究成果为设计0.5 THz的返波管提供了理论指导。 相似文献
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A spiral-shaped defected ground structure for coplanar waveguide 总被引:5,自引:0,他引:5
Jong-Sik Lim Chul-Soo Kim Young-Taek Lee Dal Ahn Sangwook Nam 《Microwave and Wireless Components Letters, IEEE》2002,12(9):330-332
The authors present a spiral-shaped defected ground structure for coplanar waveguides (DGSCPW), which can be used as a kind of periodic structure for a planar transmission line. The proposed spiral-DGSCPW adopts spiral-shaped defects on both ground planes of CPW. Due to the spiral-shaped defects, the equivalent shunt inductance and slow-wave effects increase more rapidly than the standard CPW or CPW lines combined with the conventional PBG. The modeling and analysis to extract the equivalent circuit, increased slow-wave factor, and simulated and measured performances are presented. 相似文献
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Jong-Sik Lim Young-Taek Lee Chul-Soo Kim Dal Ahn Sangwook Nam 《Microwave and Wireless Components Letters, IEEE》2002,12(12):479-481
The microstrip and coplanar waveguide transmission lines combined by a vertically periodic defected ground structure (VPDGS) are proposed. The slow-wave effect, equivalent circuit, and the performances are shown. As an application example, VPDGS is adopted in the matching networks of an amplifier for size-reduction. Two series microstrip lines in input and output matching networks of the amplifier are reduced to 38.5% and 44.4% of the original lengths, respectively, due to the increased slow-wave effects, while the amplifier performances are preserved. 相似文献
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《Microwave Theory and Techniques》1984,32(4):410-416
Using a full-wave mode-matching technique, an extensive analysis is presented of the slow-wave factor, attenuation, and characteristic impedance of a metal-insulator semiconductor coplanar waveguide (MISCPW) as functions of the various structural parameters. Design criteria are given for low-attenuation slow-wave propagation. By a proper optimization of the structure, performances comparable with or even better than those of alternative structures proposed in the literature are theoretically predicted. 相似文献
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A slow-wave electrode structure for integrated optic traveling-wave modulators in which the microwave's effective refractive index is matched to the optical wave's effective refractive index is described. The electrode structure is a capacitively loaded coplanar strip waveguide which can be formed in a single layer of metallization. Fabrication can be accomplished by a single photo-resist patterning, followed by an etching and a standard lift-off technique. Based on the use of gallium arsenide substrates and modern lithographic techniques allowing fabrication with micron scale resolution, slow-wave electrodes having a microwave effective refractive index of 3.5, as well as 50 and 75 Ω characteristic impedances are proposed. The theory of slow-wave electrodes is developed, and slow-wave electrodes have been designed, fabricated, and tested to verify the theory. Measurement results are found to agree well with the theory 相似文献
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为探索新型高效率微波器件,受其它带慢波结构器件的启发,设计了由微波预调制腔、慢波结构腔和
微波提取腔组成的新型虚阴极振荡器。研究表明,由于慢波结构的存在,束-波转换效率高于普通虚阴极振荡器,在
电压550kV、电流16kA 下,可以获得频率为1. 95GHz,1. 4GW 的周期平均功率,16%的转换效率。随后在加速器平台
进行了初步的实验研究,获得了辐射功率约600MW,频率约1. 94GHz 的微波输出,频率单一,可实现锁频。分析知,
由于阴极制作过程导致电子发射不均匀是影响效率的主要原因。实验所测得的束-波转换效率达5%,表明该结构
的高功率微波器件可以提高束波转换效率。 相似文献
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The perforated slow-wave microstrip is proposed for high-frequency microwave devices and characterised experimentally and theoretically up to 7 GHz. The perforated structure is realised with a periodic-inductive-section-maintained uniform edge-shape. The slow-wave factor is demonstrated to be 1.2 times larger than that of a conventional microstrip over a wide frequency range. The perforated slow-wave microstrip shows reduction of physical length and superior quality-factor. The proposed structure is easier to fabricate than other slow-wave structures, which require multilayer substrates 相似文献
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针对传统基片集成波导(substrate integrated waveguide,SIW)功分器设计中宽带化和小型化不易兼顾的问题,提出了一种基于慢波SIW(slow-wave SIW, SW-SIW)的功分器. 采用微带折线构成的慢波结构单元加载于SIW金属表面上,代替传统SIW连续的金属表面,与同尺寸的SIW相比,SW-SIW的截止频率下降了40%,能够实现横向尺寸的缩减,尤其当SW-SIW达到与SIW相同的相移量时,SW-SIW所需纵向尺寸更小. 所提出的基于SW-SIW的功分器在具有较宽带宽的同时实现了器件尺寸的减小. 通过测试结果可得,该功分器在8.25~12.8 GHz频带内的反射系数|S11|10 dB,相对带宽达到了43.2%,相位一致性良好且小型化效果明显,适用于紧凑型微波射频前端. 相似文献
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Measurement and Characterization of Microwave Interaction between Integrated Distributed Feedback Laser Diode and Electro-Absorption Modulator
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Fei Yuan Chao Jing Meng-Ke Wang Shang-Jian Zhang Zhi-Yao Zhang Yong Liu 《电子科技学刊:英文版》2022,20(4):375-382
Integrated electro-absorption-modulated distributed feedback laser diodes (EMLs) are attracting much interest in optical communications for the advantages of a compact structure, low power consumption, and high-speed modulation. In integrated EML, the microwave interaction between the distributed feedback laser diode (DFB-LD) and the electro-absorption modulator (EAM) has a nonnegligible influence on the modulation performance, especially at the high-frequency region. In this paper, integrated EML was investigated as a three-port network with two electrical inputs and a single optical output, where the scattering matrix of the integrated device was theoretically deduced and experimentally measured. Based on the theoretical model and the measured data, the microwave equivalent circuit model of the integrated device was established, from which the microwave interaction between DFB-LD and EAM was successfully extracted. The results reveal that the microwave interaction within integrated EML contains both the electrical isolation and optical coupling. The electrical isolation is bidirectional while the optical coupling is directional, which aggravates the microwave interaction in the direction from DFB-LD to EAM. 相似文献
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Silicon nitride films were deposited at room temperature on a single crystal silicon substrate by ECR PECVD (electron cyclotron
resonance plasma enhanced chemical vapor deposition). Effects of the microwave power and the reactive gas ratio (SiH4/N2) on the film properties, such as, refractive index and breakdown field were investigated. It turned out that the microwave
power was closely related to the change in refractive index of the silicon nitride films, while breakdown field did not change
much from 6 MV/cm. It was also found that the deposition rate, refractive index, and breakdown field were changed in a certain
way with respect to the change in SiH4/N2 ratio, which could be explained in terms of the activated chemical species concentrations in the plasma during deposition. 相似文献