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1.
The electromagnetic field analysis of a helical slow-wave structure (SWS) is carried out based on a tape-helix model incorporating the effects of space-harmonic propagating modes and the surface current on the helix over the actual metallic area of the tape. Using this analysis, closed-form expressions are derived for the shunt capacitance per unit length and the shunt conductance per unit length of the transmission-line equivalent circuit of the structure. The analysis is interpreted for the circuit attenuation constant contributed by the loss of the dielectric helix-support rods. The analysis is accurate, amenable to easy computation, and validated against published results. The analysis is subsequently used for investigating the dielectric loss in an SWS due to the backward-wave ($-$1) space-harmonic mode of propagation.   相似文献   

2.
基于夹持杆分层螺旋带模型和三维电磁场分析研究了毫米波螺旋线行波管慢波系统的导体和介质损耗。螺旋带模型中介质损耗考虑为纵向传播常数的虚部,给出螺旋带中电磁场的解析解,导体损耗由螺旋线和管壳表面的面电流不连续性获得。三维电磁场分析通过本征模法,求解单周期结构的品质因数和周期储能获得有限导电率导体和夹持杆陶瓷损耗角带来的慢波系统高频损耗。结果表明,毫米波段螺旋线的导体损耗和夹持杆的介质损耗远大于管壳导体损耗,介质损耗与陶瓷损耗角呈线性关系,对高频损耗的影响不可忽略。  相似文献   

3.
This paper describes the analysis of helix slow-wave structure (SWS) for a high efficiency space traveling wave tube that is carried out using Ansoft HFSS and CST microwave studio, which is a 3D electromagnetic field simulators. Two approaches of simulating the dispersion and impedance characteristics of the helix slow wave structure have been discussed and compared with measured results. The dispersion characteristic gives the information about axial propagation constant (Beta). Which in turn yields the phase velocity at a particular frequency. The dispersion and impedance characteristics can be used in finding the pertinent design parameters of the helix slow-wave structure. Therefore a new trend has been initiated at CEERI to use Ansoft HFSS code to analysis of the helix slow wave structure in its real environment. The analysis of the helix SWS for Ku-band 140W space TWT has been carried out and compared with experimental results, and found is close agreement.  相似文献   

4.
An analysis of rectangular folded-waveguide slow-wave structure was developed using conformal mapping technique through Schwarz’s polygon transformation and closed form 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 benchmarked for two typical millimeter-wave structures, one operating in Ka-band and the other operating in Q-band, against measurement and 3D electromagnetic modeling using MAFIA.  相似文献   

5.
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   

6.
理论分析毫米波螺旋线行波管慢波系统导体和介质损耗   总被引:1,自引:1,他引:0  
该文基于夹持杆分层螺旋带模型和3维电磁场模型分析,详细研究了毫米波螺旋线行波管慢波系统的导体和介质损耗.螺旋带模型中介质损耗考虑为纵向传播常数的虚部,给出电磁场的解析解,导体损耗由螺旋线和管壳表面的面电流不连续性获得.3维电磁场模型分析通过本征模法,求解单周期结构的品质因数和周期储能,获得有限导电率导体和夹持杆陶瓷损耗...  相似文献   

7.
本文运用螺旋坐标系计算了带状螺旋慢波线结构的耦合阻抗,本文给出了螺肇带缝隙内的电磁场解,因而明确地计算了螺旋带缝隙内的传输功率,分析这一部分功率对耦合阻抗的影响,结果发现螺肇带缝隙传输功率对耦合阻抗的影响较大,包括这一部分功率后,理论与实验符合得很好。  相似文献   

8.
衰减常数是微波传输线的重要特性参数。精确计算传输线的导体损耗衰减常数需要分析特定模式的电磁场并在导体表面积分。增量电感法将TEM或准TEM模导体损耗衰减常数的计算等效为特性阻抗对几何尺寸的偏导问题,简化分析过程。本文以同轴、带状线、微带线为例,阐述了增量电感法的原理、应用方法、适用范围,并加以讨论。  相似文献   

9.
The effects of different metallic vane-loaded helix slow-wave structures of a traveling-wave tube are proposed based on the analysis of the Fourier expansions of the exterior region with metallic vanes. The influences of the metallic vanes dimensions on the phase velocity and interaction impedance are considered in detail. The computed data is compared with the reference data in the 0−16 GHz frequency range with a good consistency. The analytical results reveal that the method of using Fourier expansions can contribute effectively to the reducing of the error between the theoretical and experimented data (around 1.2%). By analyzing the computed results, the performances of the helix slow-wave structure, with T-shaped metallic vanes are superior to the sector-shaped with the same designed parameters. Adjustments can be made to the outer radius of T-shaped metallic vanes which then control the dispersion relation showing either negative or positive, and it is similar to sector-shaped vanes by adjusting its inner radius. And with increasing the distance between the helix and metallic vanes, the dispersion characteristics and interaction impedance of the helix slow-wave structure with T-shaped/sector-shaped metallic vane are all improved.  相似文献   

10.
It is shown that, in the frequency band 3–5.2 GHz, a tape of metal conductors supports slow waves. The field structure of the surface wave in an anisotropically conducting tape is studied experimentally. It is found that the electromagnetic field of the tape has three electric and two magnetic components. Intensity distributions of all field components, the slowing factor of the surface wave, and the loss per unit length are measured.  相似文献   

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