E面分支波导耦合器的遗传算法优化设计

介绍了E面分支波导耦合器基于遗传算法的优化设计方法。详细讨论了遗传算法的优化策略和一个四端口5dB五分支波导耦合器设计实例，及该实例的等效网络综合结果和优化策略和一个四端口5dB五分支波导耦合器设计实例，及该实例的等效网络综合结果和优化后的HFSS软件仿真结果。通过比较可以发现，遗传算法优化结果完全满足期望的优化目标，经过优化设计，耦合器的频响特性有了明显改善。     

Ka波段3dB定向耦合器的设计与仿真

定向耦合器广泛地用在现代微波系统中,文中介绍了两种应用在平衡式放大器中的3dB定向耦合器。首先对微带分支线耦合器与波导耦合器进行了理论分析,然后利用电磁仿真软件HFSS,对两种耦合器进行了建模仿真。仿真结果验证了这两种定向耦合器的可实现性,最后比较了两种耦合器的性能,并且总结了各自的特点。     

Ka波段3dB定向耦合器的设计与仿真

定向耦合器广泛地用在现代微波系统中,文中介绍了两种应用在平衡式放大器中的3dB定向耦合器。首先对微带分支线耦合器与波导耦合器进行了理论分析,然后利用电磁仿真软件HFSS,对两种耦合器进行了建模仿真。仿真结果验证了这两种定向耦合器的可实现性,最后比较了两种耦合器的性能,并且总结了各自的特点。     

X 波段新型圆波导输出窗的研究

为提高功率容量水平,并满足微波系统的真空密封需求,本文通过耦合波理论以及四端口网络理论分析,设计 了一种X 波段新型圆波导输出窗,并利用全电磁仿真软件进行了验证。该新型输出窗采用矩方圆过渡器,并通过小口径 圆波导扩大至大口径圆波导。设计结果表明,在中心频率9.37GHz下,该圆波导输出窗驻波比为1.03,功率容量约为18MW。     

一种可运用于THz波段的新型定向耦合器

根据分支波导定向耦合器的工作原理,并结合考虑MEMS 刻蚀工艺,设计出一款应用于THz 波段的10dB 波导定向耦合器。该定向耦合器在传统的分支线结构上加以改进,将传统分支线耦合结构改进成新型"田"字型耦合结构,性能较好,并提高了可加工性。通过HFSS 软件仿真,该定向耦合器在0. 33 ~0. 35THz 频段内耦合度为10dB,隔离度达到30dB 以上,各端口回波损耗小于-30dB,整体插损小于0. 2dB。     

Y分支波导耦合器中弯曲损耗的研究

本论文围绕着一种用于光纤陀螺光收发模块的Y分支波导耦合器进行设计和模拟。主要对Y分支的弯曲损耗做了理论分析,在相同波导长度和分支高度下,对比余弦弯曲和正弦弯曲;TE、TM场;不同边界条件等参数和结构。通过对各项参数和结构的比较,用基于BPM(Beam propagation method)法的BPM-CAD软件对波导耦合器进行仿真模拟,得到各种结构和参数下不同Y分支波导的归一化功率和波导长度的关系,从而确定其功率损耗,最终设计出一种有效减少功率损耗的Y分之波导结构。     

宽边偏移耦合串馈合成器设计

利用四端口网络理论设计了一种宽边偏移耦合串馈合成器。首先在奇、偶模激励响应下得出了四端口耦合器的S参数,分析了耦合度、隔离度及方向性与S参数的关系,然后给出了串馈分配／合成器在功放组件内的应用原理,并结合软件仿真和工程经验设计了串馈合成器。     

电子器件

0530345改进人工神经网络算法及其在 E 面分支波导耦合器优化设计中的应用[刊,中]/许殿//微波学报.—2005,21(4).—16-19(E)将混合遗传算法用于人工神经网络,训练出全局最优的权值和偏差,解决了反向传播网络收敛于局部极值的问题。运用该方法训练出 E 面分支波导耦合器的输入输出人工神经网络模型,并以此仿真并优化其他结构的耦合器。相对于精确电磁场数值计算,前者在保证有较高仿真精度的前提下,大大提高了仿真     

对称加载铁氧体波导差相移式高功率环行器的设计

提出了一种对称加载铁氧体波导差相移式四端环行器，利用HFSS软件的仿真分析和高功率实验研究的方法对该环行器进行了仿真设计和优化，并验证了预期的高功率设计指标给出了仿真分析结果和实验数据，分析了波导中对称加载铁氧体样品对波导巾电磁场分布的影响，并就该环行器的高功率设计考虑作了讨论。     

半模基片集成波导窄壁缝隙耦合定向耦合器

半模基片集成波导(HMSIW)是最近刚刚提出的一种微波毫米波平面集成导波结构,具有品质因数高,损耗小,结构紧凑和高集成度等优点.本文基于HMSIW技术和标准印刷电路板(PCB)工艺设计并研制了6 dB、10 dB、15 dB和20 dB四种窄壁缝隙耦合定向耦合器.所设计的定向耦合器在保留与基片集成波导(SIW)定向耦合器性能相同的基础上,将体积减小了近一半.测试结果与Ansoft HFSS商用软件仿真结果基本一致,验证了所设计的定向耦合器具有小型化和性能良好等优点.     

Finite element beam propagation method for three-dimensionaloptical waveguide structures

A beam propagation method (BPM) based on the finite element method (FEM) is described for longitudinally varying three-dimensional (3-D) optical waveguides. In order to avoid nonphysical reflections from the computational window edges, the transparent boundary condition is introduced. The present algorithm using the Pade approximation is, to our knowledge, the first wide-angle finite element beam propagation method for 3-D waveguide structures. To show the validity and usefulness of this approach, numerical results are shown for Gaussian-beam excitation of a straight rib waveguide and guided-mode propagation in a Y-branching rib waveguide     

Analysis of an N-way radial cavity divider with a coaxial centralport and waveguide output ports

A field matching technique is used to analyze an N-way divider which includes a radial cavity with a coaxial central port and H-plane coupled rectangular waveguide output ports. Dielectric coated and disc ended probes at the central port are considered. The analysis is divided into two parts. Part one is associated with the modeling of the central port and part two is concerned with the modeling of the waveguide peripheral ports. The analysis is simplified by assuming that the interaction between the central port and the peripheral ports is by means of axially symmetric radial waves which are uniform with cavity's height. Based on this analysis, algorithms are developed for calculating the scattering parameters of this structure using a PC. These algorithms show good agreement when tested against a finite element package (HFSS) and against measurements     

矩形波导到圆波导模式变换器的优化设计

在圆形槽波导微波毫米波器件中,常遇到矩形一圆形槽波导的模式变换问题,而矩形一圆波导模式变换是矩形一圆形槽波导模式变换的重要组成部分。本文应用有限元方法,首先由分析N端口波导结问题过渡到两端口的矩形一圆波导模式变换器,然后针对现有模式变换器的圆端口面的电场极化方向倾斜的问题利用加圆波导段的方法进行了优化,并设计了一个新的反射微小,结构紧凑和电场极化方向竖直的矩形一圆波导模式变换器．计算结果满足了设计要求。     

偏振不灵敏硅基二氧化硅阵列波导光栅设计

以深刻蚀和热氧化工艺为基础,提出了一种新的阵列波导光栅(AWG)制备技术.这一工艺可使AWG中的波导侧向留有一硅层.采用有限元法和有限差分束传播法分别计算了存在这一硅层时的波导应力分布和有效折射率.结果表明由于这一侧向硅层的存在,使AWG中波导在水平和垂直方向的应力趋于一致,AWG的偏振相关波长明显减小.     

Full-wave analysis of a new microstrip-to-waveguide interconnectconfiguration

This paper presents a new interconnect configuration between microstripline and rectangular waveguide that yields a transition from one microstripline port to two waveguide ports. Most current transitions employ only one waveguide port. Electromagnetic coupling takes place through a slot in the narrow wall of the rectangular waveguide that coincides with a slot in the ground plane of the dielectric slab. Introduction of an E-plane waveguide fin yields additional control over the insertion loss level. The numerical method employed in the analysis, which makes use of Green's function expressions in a moment-method solution, is also described and numerical details are presented. Measured results verify the accuracy of the numerical model and illustrate that it is possible to obtain insertion loss levels of 0.25 dB with this configuration. Design data and a sensitivity analysis presented here further characterize the interconnect     

Finite element method using port truncation by perfectly matchedlayer boundary conditions for optical waveguide discontinuity problems

A powerful algorithm based on a finite element method (FEM) is newly formulated for the analysis of waveguide discontinuities. In an earlier approach, FEM was applied to the finite region with discontinuities, and a mode expansion technique was applied to the uniform waveguides that are connected to the input and output ports of finite region. Although, in the present approach, the uniform waveguides are replaced by perfectly matched layer (PML) boundary conditions, it is possible to treat periodically varying waveguide structures such as photonic crystal (PC) waveguides. A combined method of beam propagation method (BPM) and FEM is also shown in such a form that a mode expansion technique is not required. To show the validity and usefulness of the present approach, numerical examples for optical gratings, circuit components based on PC waveguides and optical directional couplers are presented     

用于毫米波焦面成像阵的介质加载波导阵元分析

分析了有望用于毫米波成像焦面阵的介质加载波导阵元，采用时域有限差分法(FDTD)计算输入特性，优化了输入基本匹配时的结构尺寸参数，计算该结构参数下的阵元与成像透镜衍射场Airy斑的耦合效率并与其它阵元做了比较。     

Equivalent network analysis of dielectric thin-film waveguide with trapezoidal cross-section

Equivalent network approach has been applied to the guided wave problems in the dielectric thin-film waveguide with trapezoidal cross-section. The results by this simple approach for the trapezoidal rib waveguide agree well with the experimental results and the results of the finite element method.     

Finite element method of lines analysis of open, periodic structures

The applicability of the finite element method of lines to the analysis of open, periodic structures is demonstrated. To validate the method and study its characteristics, the problem of transverse electric (TE) plane wave scattering from a metallic waveguide array is considered. Convergence of the solution is investigated both as a function of the mesh density and the order of the polynomial approximation used in the construction of basis functions.<>     

Phased-array radiator reflection coefficient extraction fromcomputer waveguide simulator data when grating lobes are present

Commercially available finite-element software that solves Maxwell's equations for arbitrary three-dimensional bounded structures has enabled phase-array radiator designers to perform waveguide simulator modeling of phased-array radiating elements on the computer very efficiently. Published work on waveguide simulator design has concentrated on array performance in the absence of grating lobes, a requirement for many radar applications. For such simulators, the reflection coefficient of each propagating mode at the waveguide simulator port gives the radiator reflection coefficient at a discrete scan angle. However, the design of limited scan arrays can lead to selection of an array element spacing that allows grating lobes in real space. When a waveguide simulator is modeled on the computer, and a grating lobe is present, the two waveguide modes representing the main lobe and the grating lobe will propagate in the waveguide simulator and they will be coupled together. The simulator port-reflection coefficient of either mode is not the true reflection coefficient seen by the radiating element. We describe a method for extracting the reflection coefficient of the radiating element from the waveguide simulator data when one or more grating lobes are present