非对称单脊波导几何尺度对截止特性的影响

截止波长和带宽是脊波导中的两个重要参数,采用实验方法测试脊波导的性能很难进行精确控制,而且实验设备非常昂贵。有限元法是目前电磁场数值分析中的主流方法之一,文中用有限元法对脊波导进行数值模拟分析,给出了非对称单脊波导各种几何尺度下的截止波长及主模带宽的数值计算结果,对脊波导的设计与制作具有一定的参考价值。     

有限元法的脊位于窄边的脊波导特征值分析

提出用有限元方法分析位于窄边的脊波导主模的截止波长和场结构图以及单模带宽特性，推导出用有限元法计算相关参数的计算公式。编程计算了双脊、单脊和不对称脊波导的特征值，求解了三种脊位于窄边的脊波导的传输特性，并给出了截止波长和单模带宽曲线以及场结构变化。     

脊位于窄边的四种加载介质波导传输特性的有限元计算

运用矢量有限元方法对脊位于窄边的四种加载介质双脊波导的主模截止波长和单模带宽特性进行了计算和分析,四种波导分别为脊位于窄边的加载介质双脊矩形波导、加载介质双脊梯形波导、加载介质双脊V形波导以及加载介质双脊椭圆形波导。计算结果表明,脊位于窄边的四种加载介质双脊波导的两种传输特性总体相似,和脊位于宽边相比,脊位于窄边的主模归一化截止波长和单模带宽总体小很多,且脊位于宽边时的特性变化趋势比脊位于窄边时剧烈。这些计算结果将有助于微波器件及微波系统的设计。     

Eigenmodes of sectoral coaxial ridged waveguides

The results of numerical investigation of sectoral coaxial ridged waveguides eigenmodes of two configurations (with a ridge on inner or outer wall) for different cross-section dimensions are presented. In particular, dependences of cutoff wave numbers on geometrical dimensions ratios for first four modes are investigated, electric field components distributions for these modes have been obtained and the optimization of sectoral coaxial ridged waveguides has been carried out to provide maximal single-mode operation frequency band. Two optimal configurations of waveguides with single-mode operation bandwidth ratio 5.6:1 are obtained. It is shown that smaller cross-section dimensions at the fixed single-mode operation frequency band has the waveguide with the ridge at the inner round wall. The size of the gap between the ridge and the round wall of optimal waveguide is identical for both configurations and is determined by the required ratio of cutoff frequencies of two lower TE modes. Calculations are conducted utilizing the mathematical model obtained in [1] by the integral equation technique with the correct account of singular behavior of the field at the ridge.     

组合形变对三角形脊波导传输特性的影响

脊波导的传输特性包括截止波长、单模带宽、衰减常数、功率容量以及特性阻抗。脊波导器件在装配使用中所产生的错位形变与边侧形变很难单独发生,因此,有必要研究错位形变、底部形变、单侧形变、双侧形变结合的组合形变。利用ANSYS建立模型与MATLAB编写有限元程序相结合的方法计算了三角形脊波导组合形变对其传输特性的影响。研究结果表明,组合形变对三角形脊波导的截止波长、单模带宽影响较小,三边形变与错位底部形变对三角形单脊波导功率容量、衰减常数及特性阻抗影响较大,研究结果将为三角形脊波导的应用提供了理论依据。     

两种变形双脊波导传输特性的分析研究

为了寻找最佳传输特性的对称双脊波导结构,提出了圆形和椭圆形两种变形对称双脊波导,采用有限元的方法,研究了圆形和椭圆形两种变形对称双脊波导对传输特性的影响。计算了脊尺寸变化时的截止波长和单模带宽,给出了主模场结构图以及变形对截止波长和单模带宽影响的相应的关系曲线,并分析了传输特性随对称脊波导结构尺寸的变化情况。该研究结果对变形双脊波导的应用和研究提供了参考,并为脊波导器件的小型化提供了指导。     

不对称脊波导的传输特性

提出了用有限差分方法分析不对称脊波导主模的截止波长和场结构图等传输特性,推导出用有限差分方法计算相关参数的公式。脊波导中主模的截止波长可随脊位置的变化而变化。文中编程计算了不对称脊波导、L型波导脊位置变化时截止波长和场结构的变化规律,给出了计算数据和曲线图。计算结果与相关文献非常吻合,证明文中提出的计算方法和计算结果是正确和可行的。     

基于时域有限差分法填充介质梯形脊波导研究

为了研究填充介质对脊波导截止特性的影响,文章采用FDTD(时域有限差分)法计算了填充介质梯形双脊波导在TE(横电波)模式下的截止特性随几何尺寸的变化,并给出了关系曲线。结果表明,脊间距越小,填充介质的相对介电常数越大,截止波长越长,单模带宽越窄。研究结果丰富了现存填充介质波导数据,有助于填充介质波导的设计和工程应用。     

基于有限元法的新型双脊波导传输特性的研究

文章采用有限元法研究了圆形和椭圆形两种变形对称双脊波导对传输特性的影响.计算了脊的尺寸变化时的截止波长和单模带宽,给出了主模场结构图以及变形对截止波长和单模带宽影响的关系曲线,并分析了传输特性随对称脊波导结构尺寸变化的情况.通过这些研究,能够为变形双脊渡导的应用和研究提供有价值的参考.     

脊槽波导主模截止特性研究

为了研究脊槽波导主模截止特性,采用亥姆霍兹方程的有限差分格式,计算在窄边与宽边比为0.45、槽的高度与窄边比为0.4的条件下,脊槽波导中脊和槽的几何尺寸在中间位置连续变化时的归一化截止波长。并且计算了当脊宽为0、脊槽间距为窄边长度加槽高度,即脊槽波导的脊消失,成为单槽波导的归一化截止波长。并将计算结果与单槽波导和单脊波导的进行对比。结果表明,脊槽波导的截止特性较单脊波导和单槽波导更加良好。     

Cutoff wavelength of periodically segmented waveguides in Ti:LiNbO3

The cutoff wavelength for Ti:LiNbO₃ periodic segmented waveguides (PSWs) with different duty-cycles and of continuous waveguides has been measured for both polarizations, PSWs are described by an equivalent continuous waveguide and, using this model, a universal relationship between the cutoff wavelength of PSWs with different duty-cycles is proposed and verified experimentally     

Analysis of a ridge waveguide using overlapping T-blocks

A T-block (TB) approach is proposed to analyze the dispersion relation of a ridge waveguide. The field representations of a TB are obtained with the Green's function and mode-matching technique. Rigorous, yet simple dispersion equations for symmetric and asymmetric ridge waveguides are presented using a superposition of overlapping TBs. The rapid convergence characteristics of the dispersion equation are illustrated in terms of the cutoff wavenumbers. A closed-form dispersion relation, based on a dominant-mode approximation, is shown to be accurate for most practical applications such as couplers, filters, and polarizer designs.     

基于有限元法分析设计双奇异脊波导

本文应用电磁场有限元法分析了双奇异脊波导的传输特性,编程分析计算了不同横截面的双奇异脊波导的主模工作带宽。并比较了脊的尺寸和间距不同时,其主模截止波长和单模带宽的变化规律,得到了相应的数值解。讨论了网格划分对计算结果的精确度的影响。为双奇异脊波导的设计和研究提供了参考。     

Determination of cutoff frequencies of a square waveguide with a concentric inner circular boundary

The determination of cutoff frequencies in perfectly conducting square waveguides with an inner circular boundary (TM mode) is investigated. The given domain is transformed into an annular region and the transformed partial differential equation is solved by means of a variational technique.     

窄边双脊波导传输特性分析

传统脊波导的脊位于长边,与矩形波导相比,具有较大的截止波长、较宽的单模带宽和较低的阻抗等优点。这方面的论文很多。迄今为止,没有关于窄边双脊波导的研究报道。本文采用亥姆霍兹方程有限差分法分析,从而获得精确的窄边双脊波导传输特性参数。计算结果与传统的双脊波导相比较,窄边双脊波导减小了单模带宽,因此可作为有效的脊带宽滤波器。     

不对称脊波导脊位置对主模截止波长的影响

用有限差分方法分析不对称脊波导中脊位置变化时对主模截止波长的影响。截止波长可以通过脊位量的调整而调整。并给出了一些计算数据。     

Fabrication of ridge waveguides in LiNbO3 thin film crystal by proton-exchange accelerated etching

A simple fabrication method of adhered LiNbO₃ ridge waveguides by accelerated etching of the proton-exchanged region is proposed and demonstrated. The waveguides were fabricated and tested at 1.55 mum wavelength. Strongly confined guided modes were obtained. The waveguides are suitable for efficient nonlinear-optic wavelength conversion devices.     

Electrodynamics boundary problem solution for sectoral coaxial ridged waveguides by integral equation technique

The electrodynamics eigenmodes boundary problem for sectoral coaxial single-ridged waveguides is solved by the integral equation technique utilizing the introduced system of orthogonal basis functions, which correctly take into account the singular field behavior at the ridge. The formulas obtained allow to compute cutoff wave numbers and electric and magnetic fields distributions of TE and TM modes in the presence of the ridge either on the outer or on the inner wall of the waveguide. The analysis of the dependence of cutoff wave numbers convergence on the type and the amount of basis functions and partial modes has been carried out. It is shown that for obtaining 0.1% residual error it is necessary to utilize in two times more unorthogonal basis functions, which correctly take into account singularity at the ridge, than introduced orthogonal basis functions, which correctly take into account singularity at the ridge, and in five times more orthogonal trigonometric basis functions, which don??t take into account singularity at the ridge. Besides the computing time increases in 4 and in 20 times, respectively.     

脊槽波导主模截止波长研究

为了满足微波传输系统性能的某些需求,各种结构形状的新型波导应运而生。采用有限差分法,利用MATLAB计算了脊槽波导中脊和槽的几何尺寸在中间位置连续变化时的主模截止波长,并对计算结果进行了对比分析,得出了主模截止波长随着脊的高度、宽度、槽的宽度等变化而变化的一些相关结论,为设计脊波导器件提供了参数。     

On the Design of Dielectric Loaded Waveguides

Rectangular waveguides partially filled with a dielectric slab in the E plane can provide an alternative to ridged waveguides in broad-band systems. It is shown that by an appropriate choice of the dielectric constant, maximum power handling capacity for a given bandwidth and cutoff wavelength can be achieved. This power-handling capacity is much higher than for ridged waveguides. Attenuation and the effect of the first longitudinal-section-electric (LSE) mode on bandwidth are also discussed.