波导耦合谐振腔的实验研究

采用微波波导耦合谐振腔激励ＣＯ２激光器，具有结构简单，易于调谐和调配的特点。文中给出了实验结果。     

毫米波波导成型技术

用活动模芯代替钢带是毫米波波导弯曲成型的有效方法,该工艺的关键是模芯的设计与制造。采用活动模芯弯曲毫米波波导,重点讨论了模芯尺寸、模芯形状和回跳角对波导尺寸和表面粗糙度的影响,并对该工艺制备的样品进行了测定。结果表明:当模芯尺寸与波导内腔实际尺寸差值在0~0.02 mm,不同的弯曲半径和弯曲角度给予不同的回跳角预设值,可以制造出满足设计要求的弯波导。     

等离子体波导中电磁波的色散特性

本文对全部充满等离了体且有外加恒定磁场手圆柱波导的电磁波色散特性进行了分析，对原有的色散方程进行了修正，在色散图上提出了一种新的电磁波分类方法，南原有的波分类相比，这种分类更为合理，同时，通过对新的色散方程进行数值求解，发现了原有计算结果的一些错误。     

Longitudinal Wave Propagation in Dielectric Waveguide Array

Based on the established rigorous theory for two-dimensionally periodic (2DP) medium, Longitudinal propagation in Dielectric Waveguide Array (DWA) was analyzed in detail. Firstly, given longitudinal wave vector (k _z), Brillouin dispersion relations between transversal wave vectors were analyzed. Interactions between space harmonics were also studied. Secondly, on condition that transversal wave vector k _x equaled k _y, dispersion relations between longitudinal and transversal wave vectors were analyzed in detail. Because of interactions between space harmonics increasingly getting stronger with k _z or modulation coefficients increasing, stop-bands could be distinctly displayed and thus longitudinal propagation in DWA could be comprehensively analyzed. The applications about longitudinal propagation in DWA were also discussed.     

光子晶体线缺陷构成的波导中光的传输

对由光子晶体线缺陷构成三种形式的光波导,用有限差分法研究光波在其中的传播规 律,发现不同形状的波导能够导引不同频率的光波。低频光波易从直波导传输,而折线型波导频谱通带较窄,低频光波不能通过。研究结果为光子器件的设计提供了理论依据。     

波导平面电路定向耦合器及CAD

本文利用平面电路耦合孔阵作为波导侧壁耦合的定向耦合器电路;该平面电路具有调节耦合度方便、加工简单、生产成本低的特点.本文给出了计算机辅助设计的方法和测试结果.     

Operating Parameters Optimization of Miniature Optically Pumped Cavity NH3 Submillimeter Wave Laser

By means of the iteration method, the output power density of the miniature optically pumped NH₃ submillimeter wave (SMMW) laser was calculated based on the density matrix equations of a quantum system. Optimization of operating parameters including operating gas pressure, reflection coefficients of input and output meshes of the laser were studied systematically. In the paper, the concepts of the average activated length and the synthetical optimum value were defined, and some rules of the optimization were explained successfully. Experimentally, a cavity NH₃ SMMW laser that was composed of a pair of inductive metallic meshes and pumped by TEA-CO₂ 10R(8) line was used. The experimental results were in good agreement with our theoretical calculations.     

共面波导结构MEMS滤波器的设计

设计了一种基于共面波导结构的 MEMS 带阻滤波器。利用计算机软件 HFSS 模拟出滤波器的带阻中心频率约为 22 GHz、损耗 19.86 dB、阻带宽度为 5 GHz,而设计大小仅为 1 000 μm×1 100 μm×400 μm。只需改变设计参数,即可获取其它频段的带阻滤波器。该滤波器具有阻带高、插入损耗低、尺寸微小、加工容易等特点。在微尺寸条件下分析了滤波器结构的热应力特性,利用大型有限元软件 ANSYS 模拟表明在–50~+80℃的温度范围内,结构不会产生变形,表明了器件有良好的可靠性。     

速调管矩形波导加载输出腔的粒子模拟

利用三维PIC 软件,首次建立与速调管输出腔外接矩形波导耦合装置几何尺寸完全一致的计算模型,对S 波段矩形波导输出腔加载做了设计和优化,在工作电压80 kV,束流45 A,工作中心频率为2.85 GHz 条件下,得到了1.43 MW的输出功率,3 dB 带宽达到了6%,经过实验证明,理论仿真计算与实测结果是吻合的。     

基于MEMS共面波导腔的带阻滤波器的设计

应用计算机辅助设计了一种基于共面波导结构的MEMS带阻滤波器.研究了微尺度电磁学、力学、温度等效应.利用ANSOF的HFSS软件模拟分析了滤波器的损耗参数,并应用ANSYS软件分析复合结构的热应力分布,得出了阻带中心频率在18GHz的MEMS带阻滤波器件,提供了一些有意义的理论分析及应用.     

Graphene-Based\ Waveguide Terahertz Wave Attenuator

We design an electrically controllable terahertz wave attenuator by using graphene. We show that terahertz wave can be confined and propagate on S-shaped graphene waveguide with little radiation losses, and the confined terahertz wave is further manipulated and controlled via external applied voltage bias. The simulated results show that, when chemical potential changes from 0.03 into 0.05 eV, the extinction ratio of the terahertz wave attenuator can be tuned from 1.28 to 39.42 dB. Besides the simplicity, this novel terahertz wave attenuator has advantages of small size (24?×?30 μm²), a low insertion loss, and good controllability. It has a potential application for forthcoming planar terahertz wave integrated circuit fields.     

Applicability of Cavity Modeling Technique to Analyze Complex Waveguide Structures Involving Cavity Cross Couplings

Wireless Personal Communications - In this paper, we propose modulation and coding scheme level drop scheme for LTE evolved multimedia broadcast/multicast service (eMBMS) by transmitting additional...     

矩形波导加载双间隙输出腔的粒子模拟

利用三维PIC软件,建立与速调管双间隙输出腔外接矩形波导耦合装置几何尺寸完全一致的计算模型,对S波段矩形波导输出腔加载做了设计和优化,在工作电压80 kV,束流45 A,工作中心频率为2.9GHz条件下,得到了1.45 MW的输出功率,3 dB带宽达到了12％,经过实验证明,理论仿真计算与实测结果是吻合的.     

正弦波导慢波结构的研究

提出了一种新型的可用于产生、放大毫米波和太赫兹波的正弦波导慢波结构。该结构有天然的带状电子注通道,具有低欧姆损耗和弱反射,且易于加工等独特性质。计算了慢波结构的高频特性,粒子模拟分析了该慢波结构在220GHz行波管及220GHz返波管中的应用潜力。研究结果显示,正弦波导将是一种很有潜力的可应用于大功率毫米波及太赫兹辐射源的慢波结构。     

High Unloaded Qs MM Wave WDR Filters Designing

The designing results of original high unloaded-Q waveguide-dielectric filters (WDFs), are discussed. The basic physical ideas, underlying the unique design of both narrow- and wide-band filters with a widened region of suppression up to a doubled working frequency and higher, with low losses (0.2-0.5 dB), are set forth; some of their parameters in the frequency range from 8 GHz up to 80 GHz, are brought forward. The distinctive features of a WDFs are observed and the perspective directions of their development and application are predicted.     

光波在含特异材料的环形腔内的传输特性

基于光线传输矩阵理论,研究了含特异材料环形腔内光波光斑半径和相对光强的分布特性.结果表明:以负折射率材料内部作为起始位置,光波传输一周后,子午面和弧矢面光斑半径均较大,中心光强较弱.当光波离开负材料后,光斑半径迅速减小,由于凹面镜的影响,在其表面又达到极大值,但较负材料内部光斑半径小很多.当光波传输起始点远离凹面镜后,光斑半径依次减小,在两平面镜中心达到最小值,此时中心光强最大.在此基础上,分析了负材料长度和介质折射率对光波束腰半径的影响.研究发现,介质长度对环形腔内子午面和弧矢面的束腰半径影响较小,但介质折射率对负材料内部束腰半径的影响较大.     

EM Wave Propagation in Ferrite-Filled Transversely Magnetized Circular Waveguide

This paper presents a rigorous method of solving Maxwell's equations for ferrite-filled transversely magnetized circular waveguide. Solutions for cylindrical coordinate system are derived by using power series expansion of the field's potentials. Complex propagation constants are obtained by applying boundary conditions and representing fields in partial cylindrical modes. Plane wave representation of propagation is also considered. Numerical calculations of the propagation constants as well as the dominant waveguide mode reflection and transmission from a ferrite-filled waveguide section are presented.     

用COMSOL实现圆波导中电磁波的可视化

为了直观描述金属圆波导中电磁场复杂的空间分布,本文用Comsol软件对金属圆波导中的TE11模、TE01模、和TM01模的电磁场结构进行动态仿真.将电磁场中的抽象概念形象化、可视化,使学生看清电磁场分布的宏观概况和细节变化,开拓了视野,同时加深了学生对电磁波传播特性的理解.     

Magnetostatic Wave Propagation in a Finite YIG-Loaded Rectangular Waveguide

The propagation of magnetostatic waves (MSW) in a waveguide partially loaded with a low-loss ferrite slab is investigated theoretically. The most common low-loss ferrite material used for MSW propagation is epitaxial yttrium iron garnet (YIG). A YIG slab is placed inside and along the guide and not in contact with the sidewalls of the wavegnide. The dc magnetic field is assumed to be parallel to the YIG slab and perpendicular to the direction of propagation. Using the integral equation method, the dispersion relation is found to be an infinitely large determinant equal to zero. Proper truncation of this determinant and numerical analysis to find its roots are carried out in this work. It is seen that in order to obtain high values of group time delay, the YIG slab must be narrow and placed at the bottom of the guide. On the other hand, to maximize the device bandwidth, a narrow YIG slab positioned at the top inside surface of the waveguide is preferred. It is also noticed that there exists a tradeoff between the time delay and the device bandwidth and that maximization of one property leads to a poor value in the other. Thus, some design compromises should be made. It is also observed that the frequency range of operation of the device can be adjusted by an external magnetic bias field. This property of tuning the device to operate in any frequency range adds an extra dimension of flexibility to the operation and also to the design of these devices.