共查询到20条相似文献,搜索用时 15 毫秒
1.
Chengfang Fu Bo Zhao Yudong Yang Yongfeng Ju Dingli Yang Bo Chang Xiaofeng He 《Journal of Infrared, Millimeter and Terahertz Waves》2016,37(11):1106-1116
A simple equivalent circuit analysis of the frame–rod slow-wave structure (SWS) on dielectric substrates of a traveling-wave tube (TWT) is developed, using the quasi-TEM approximation approach for the dispersion and coupling impedance characteristics of the structure. Moreover, the obtained complex dispersion equation and coupling impedance are numerically calculated. The calculation results by our theory method agree well with the results obtained by the 3D EM simulation software HFSS. It is shown that the dispersion of the frame–rod circuit is decreased; the phase velocity is reduced and the bandwidth becomes greater, while the coupling impedance decreases after filling the dielectric materials in the frame–rod SWS. In addition, a comparison of slow-wave characteristics of this structure with a rectangular helix counterpart is made. As a planar slow-wave structure, this structure has potential applications in compact TWTs based on the micro-fabrication technology, which could be scaled to millimeter wave, even to THz frequency. 相似文献
2.
To enhance the strength of beam-wave interaction and improve the performance of gain, the double-groove loaded folded-waveguide slow-wave structure (SWS) is proposed for millimeter traveling-wave tubes (TWTs). In the first part, the expressions for the dispersion and the interaction impedance of this novel structure are obtained by using matching conditions of the RF fields. Ansoft HFSS is also used to calculate the high frequency characteristics. The simulation results from HFSS agree with the theoretical results. Numerical calculation for different combinations of the groove width and depth is carried out to study the influence of groove loading on the properties of this novel circuit. In the second part, a linear theory of a double-groove loaded folded-waveguide TWT is developed and calculated for analyzing the effect of groove dimensions on the property of small signal gain. The investigation results indicate that the interaction impedance is obviously raised up and the small signal gain are enhanced by loading groove in the FWSWS. 相似文献
3.
Mukesh Kumar Alaria A. K. Sinha V. Srivastava 《Journal of Infrared, Millimeter and Terahertz Waves》2009,30(7):651-656
This paper describes the design of tip loss profile on support rod for a high gain, high efficiency helix TWT. The tip loss
profile at sever ends for the input and the output section of the helix slow wave structure has been designed for return loss
at severs ends better than -20 dB. The experimental results have been carried out in the input and the output section of the
helix assemblies for the high gain helix TWT to find the return loss in the region of carbon coated tip loss on the support
rods. The experimental result has been compared with the simulated performance for the return loss at the sever ends. The
design of tip loss profile on the support rod for helix TWT has been carried out in real situation using Ansoft HFSS. A good
agreement has been found in the simulated and experimental results. 相似文献
4.
Mukesh Kumar Alaria A. K. Sinha A. Bera V. Srivastava 《Journal of Infrared, Millimeter and Terahertz Waves》2008,29(12):1083-1090
The main objective of the paper is to make an efficient design of the input and output coaxial coupler for a helix TWTs. An approach has been developed for the efficient design and analysis of the coaxial couplers in the practical situation. Normally multi-section impedance transformer approach is used for any wide band coupler. For a space helix TWT, coupler should be wide bandwidth and small size. In this case coupler is matched with helix slow wave structure and the standard 50-ohm connectors. The simulated return loss (dB) profile for different type of couplers is obtained by using Ansoft HFSS, CST microwave studio and compares those with experimental results. The tip loss design at sever ends for the input and the output section has been also optimized. 相似文献
5.
本文研究了一种具有新型分立介质支撑的翼片加载螺旋带慢波系统,该种慢波系统具有较高的功率容量和较宽的带宽.通过用切比雪夫多项式来展开螺旋带上的面电流,用真空层来模拟螺旋带的厚度,用均匀分层介质来等效新型分立介质支撑,考虑到过渡连接金属块的影响,用场论的方法得到了非常实用的色散方程和耦合阻抗的表达式,同时进行了HFSS模拟,发现用场论的方法所得出的结果与用HFSS模拟的结果吻合良好.本文的结果对这种新型慢波结构的设计具有指导意义. 相似文献
6.
Zhaoyun Duan Yubin Gong Yanyu Wei Wenxiang Wang Minzhi Huang 《International Journal of Electronics》2013,100(5):309-318
In order to enhance the power capability of the helix travelling wave tube, a novel tape helix slow wave structure (SWS), which is supported by helically arrayed radial dielectric-support posts, is developed. Each dielectric post can be easily brazed with the tape helix and the metal envelope by means of a special soldering. This kind of supporting mode can protect the dielectric supporting posts from being broken by the thermal stress in the case of high temperature. A hybrid model is set up in consideration of the influences of both the radial thickness of the tape helix and these discrete dielectric-support posts. The dispersion equation and interaction impedance of the helical SWS are obtained. The calculated results using this hybrid model presented in the paper show good agreements with the HFSS simulation results. All the results presented here can provide a good basis for designing the novel tape helix SWS. 相似文献
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Jianxiang Xie Yanyu Wei Yubing Gong Jin Xu Wenxiang Wang 《Journal of Infrared, Millimeter and Terahertz Waves》2005,26(10):1473-1489
This paper gives the investigations of the fundamental wave of a free elliptical helix slow-wave structure (SWS) with arbitrary eccentricity. The wave properties including the phase velocity characteristics, interaction impedance and the longitudinal electric field distribution of this mode has been fully studied. It is found that, when the eccentricity increases, the interaction impedance and the operating frequency of such SWS will be improved, which allows to have a higher gain and operating in a higher frequency band. Furthermore, the field configuration is different from that of a round helix; the azimuthal distribution of the E-field follows with the angular Mathieu function of the first kind, even with mode of zero. In radial, E-field is elliptical surface wave. When the eccentricity tends to zero, all the characteristics will be smoothly degenerates to the case of round helix correspondingly. 相似文献
9.
本文采用矩形波导加载光栅的慢波结构作为太赫兹返波管的高频结构,通过理论分析和电磁仿真研究了该慢波结构的色散特性和互作用阻抗,理论分析结果和仿真结果能很好地吻合。在理论分析的基础上,设计了一个中心频率为340GHz的返波管,经粒子模拟软件计算,在较低电流密度的情况下该返波管输出功率达100mW且可调带宽约30GHz。 相似文献
10.
11.
The measurement accuracy of the interaction impedance for a helical slow-wave structure (SWS) using the nonresonant perturbation method has been studied using conductive wire perturbers with different diameters. Data obtained by the measurement were compared with a rigorous numerical analysis. It is shown that the measured values of the interaction impedance for the helical SWS converge to those obtained by using a three-dimensional finite-element computational method when the diameter of the perturber is reduced to less than 10% of the helix diameter 相似文献
12.
本文选用矩形耦合腔作为太赫兹扩展互作用振荡器(EIO)的慢波结构,鉴于其结构的复杂性,采用等效电路方法计算其色散.详细研究了腔体和耦合槽的电路参数,计算了不同结构尺寸、圆形和矩形电子通道的0.12THz和0.225THz慢波结构的色散特性.并采用专业电磁软件,研究了不同结构参数下的色散特性、耦合阻抗和特征阻抗.通过对色... 相似文献
13.
Zhigang Lu Yubin Gong Yanyu Wei Wenxiang Wang 《Journal of Infrared, Millimeter and Terahertz Waves》2006,27(8):1095-1108
A new type of partial-dielectric-loaded rectangular waveguide grating slow-wave structure (SWS) for millimeter wave traveling wave tube (TWT) is presented in this paper. The radio-frequency characteristics including the dispersion properties, the longitudinal electric field distribution and the beam-wave coupling impedance of this structure are analyzed. The results show that the dispersion of the rectangular waveguide grating circuit is weakened, the phase velocity is reduced and the position of the maximum E z is basically invariant after partially filling the dielectric materials in the rectangular waveguide grating SWS. Although the coupling impedance decreases a little, it still keeps above 40 Ω. 相似文献
14.
分析了一种适用于E波段81~86 GHz空间行波管的新型慢波结构——折叠矩形槽波导.折叠矩形槽波导来源于传统的矩形槽波导,将E面沿其纵向来回弯曲而形成.利用电磁场仿真软件Ansoft HFSS设计优化并最终确定了E波段折叠矩形槽波导的关键几何尺寸.同时,模拟仿真出了折叠矩形槽波导在中心频率f=83.5 GHz处的耦合阻抗沿x和y方向上的变化趋势,得出其可通过加载带状电子注获得更高的平均耦合阻抗.利用CST粒子工作室模拟得出:折叠矩形槽波导行波管在中心频点83.5 GHz处输出功率为210 W,电子效率达到8.05%. 相似文献
15.
Lu Zhigang Gong Yubin Wei Yanyu Huang Yu Wang Wenxiang 《Journal of Infrared, Millimeter and Terahertz Waves》2006,27(6):791-807
The rectangular waveguide grating slow-wave structure (SWS) with arbitrary shaped grooves is presented and analyzed in this paper. As an all-metal slow-wave circuit, it has properties that can be used in high-power millimeter-wave or sub-millimeter wave traveling wave tube (TWT). The unified dispersion equation and the expression of coupling impedance are obtained in this paper by means of an approximate field-theory analysis, in which the profile of the groove is approximately replaced by a series of steps and the field continuity at the interface of two neighboring steps together with the field matching conditions at the interface between the groove region and the interaction region are employed. A rectangular groove SWS was manufactured and the cold measurement was made. The experimental data are in good agreement with the numerical calculation. The derived transcendental equations are resolved numerically for four classical structures such as rectangular, dovetail, ladder and cosine. Finally, taking the rectangular waveguide grating SWS with rectangular grooves for example, the influences of physical dimensions on dispersion relation and coupling impedance are discussed. 相似文献
16.
M. Sumathy K. J. Vinoy S. K. Datta 《Journal of Infrared, Millimeter and Terahertz Waves》2009,30(2):151-158
A simple equivalent circuit model for the analysis of dispersion and interaction impedance characteristics of serpentine folded-waveguide
slow-wave structure was developed by considering the straight and curved portions of structure supporting the dominant TE
10-mode of the rectangular waveguide. Expressions for the lumped capacitance and inductance per period of the slow-wave structure
were derived in terms of the physical dimensions of the structure, incorporating the effects of the beam-hole in the lumped
parameters. The lumped parameters were subsequently interpreted for obtaining the dispersion and interaction impedance characteristics
of the structure. The analysis was simple yet accurate in predicting the dispersion and interaction impedance behaviour at
millimeter-wave frequencies. The analysis was benchmarked against measurement as well as with 3D electromagnetic modeling
using MAFIA for two typical slow-wave structures (one at the Ka-band and the other at the W-band) and close agreement observed. 相似文献
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18.
Wenqiang Lei Zhonghai Yang Li Liao Ping Liao 《International Journal of Electronics》2013,100(3):161-172
The dispersion equation and interaction impedance of a U-shaped vane-loaded helical slow-wave structure (SWS) is obtained by considering the azimuthal space harmonic in the non-vane region and the helical tape thickness, using the field theory matching method in the azimuthal field discontinuity. The theoretical calculation by electromagnetic analysis is consistent with the simulation result by MAFIA, which can explain some physical essence of the SWS. In the helical SWS, negative dispersion is reported to reduce the second harmonic content of a wideband travelling-wave tube at the low-frequency end of the band. When the SWS is assembled, the support rods are easily located in the groove of the vane. The solution provides a new instruction method for other types of vane-loaded helical SWS. 相似文献
19.
XiaoFang Zhu ZhongHai Yang Bin Li 《Journal of Infrared, Millimeter and Terahertz Waves》2005,26(12):1713-1725
Theoretical simulation of the dispersion and interaction impedance characteristics of an inhomogeneously-loaded helical slow-wave structure is validated. The structure is supported by double-curve-shaped rods which are smoothed out into a number of dielectric tubes with their respective effective permittivity values. The effects of the helix thickness are taken into account by considering a free-space gap equal to the difference between the mean helix radius and the outer helix radius. Moreover, the helix tape model is used instead of the simpler sheath-helix model. The theoretical predictions are compared with those of MAFIA simulation. The dispersion error is found to be within 3–6 percent and the impedance characteristic is in great agreement with that of MAFIA simulation. At last, for the sake of comparison, the cold-test characteristics under sheath-helix model are also provided. 相似文献
20.
XiaoFang Zhu ZhongHai Yang Bin Li JianQing Li Li Xu 《Journal of Infrared, Millimeter and Terahertz Waves》2010,31(2):237-248
To validate HFCS-I, a newly developed design tool for high frequency circuits of microwave tubes, the high-frequency parameters
(including dispersion, interaction impedance and attenuation constant) of a typical helical slow-wave structure (SWS) for
millimetre wave travelling-wave tube are calculated by HFCS-I and MAFIA. Both the direct calculation method and the Non-Resonant
Perturbation (NRP) technique are adopted to get the interaction impedance. The obtained high-frequency parameters from HFCS-I
and MAFIA are compared in detail and the consistency has proved the reliability and validity of HFCS-I. 相似文献