CST频域求解器讲解.doc

版主你好，我把中文写在前，英文在后，这样翻译方便校对，不知你的意见如何？我离开学校有一年了，英语退步很大，另外CST频域求解这一块我也不精通，翻译得不好，请指正。虽然我自己翻译完全，有些内在含义不是很能理解。请指正!频域求解器(Frequency Domain Solver)一频域求解器预览（Frequency Domain Solver Overview）假定场和激励是时谐相关的，麦克斯韦方程组可能转换到频域。场可以用与瞬态场相关的相量来描述，瞬时场是把相量和时间因子相乘然后取实部得到。 通用的频域求解器解决的是一次一个频率和在扫频过程中的一系列自适应选择的频率的问题。The general purpose Frequency Domain Solver solves the problem for a single frequency at a time, and for a number of adaptively chosen frequency samples in the course of a frequency sweep. 对每一个频率样本，线性方程系统可以通过迭代（例如共轭梯度）或者稀疏直接求解器解决。For each frequency sample, the linear equation system will be solved by an iterative (e.g., conjugate gradient) or sparse direct solver. 方程的解包含在给定频率下的场分布和S参数。The solution comprises the field distribution as well as the S-parameters at the given frequency. 频率取样可以用离散算法并行计算得出（包括提交单一细微的计算或者并行运行参数扫描和优化）。看在频域求解器的参数和下面的离散算法和自适应取样的部分。Frequency samples can be calculated in parallel using distributed computing (besides submitting a single remote calculation, or running parameter sweeps and optimizations in parallel), see the corresponding frame in the Frequency Domain Solver Parameters and the section distributed computing and adaptive sampling below. 对于模型几何结构的离散化，在求解器开始运行前六面体网格和四面体网格可以根据需求适当选择。For the discretization of the geometry, the hexahedral mesh as well as the tetrahedral mesh may be chosen on demand right before the solver start. 如果仅仅需要S参数，那么“快速S参数谐振” 求解器是很有趣的。If only S-parameters are required, then the Resonant: Fast S-Parameter solver is of interest. 这个求解器目前能处理无损结构、小介质损耗、波导和离散端口。This solver can currently handle loss-free structures, small dielectric losses, waveguide and discrete ports. 除开S参数，场监视器有意义，那么“S参数和场谐振”求解器可以代替主要目的求解器。If, in addition to the S-parameters, field monitors are of interest, then the Resonant: S-Parameter, fields solver may be used instead of the General Purpose solver. 这个求解器目前能处理无损结构、波导和离散端口。This solver can currently handle loss-free structures, waveguide and discrete ports. 对所有这些求解器，在S参数计算完成后很有可能有效计算出电磁场监视器。For all these solvers it is possible to efficiently calculate electric and magnetic field monitors after an S-Parameter calculation has finished. 在求解器开始前无需定义监视器。It is not necessary to define monitors before the solver starts. 在一维坐标预览中进一步了解需要在坐标轴轴标记的地方看计算场。See Calculate field at axis marker in the 1D-Plot Overview for further details. 谐振求解器模块仅仅在六面体网格里有效。The resonant solver modules are only available on hexahedral grids. 另外，谐振法不需要任何频率取样，因此下文中的描述不再对它适用。Additionally, the resonant methods do not require any frequency sampling, and therefore the description hereinafter does not apply to them.频域求解器主要用途的应用领域（Areas of application of the general purpose frequency domain solvers） 散射参数矩阵（S参数） Scattering parameter matrices (S-Parameter) 在不同频率下电磁场的分布（见“监视器”一节）Electromagnetic field distributions at various frequencies (see monitors) 天线辐射图和相关的天线参数（见“监视器”一节） Antenna radiation patterns and relevant antenna parameters (see monitors) 由单元组成或者在周期边界条件下的无限阵列的单元（例如模拟无限给定相位的天线阵列和频率可选的表面）Unit cells of infinite arrays with unit cell or periodic boundary conditions (for example to simulate infinite phased antenna arrays and frequency selective surfaces) 网络的提取Spice network extraction 频率取样（Frequency sampling）如果你对结构的S参数感兴趣，取样法对计算时间有很大的影响。If you are interested in structures S-parameters, the sampling method has a large influence on the calculation time. 自动选取的频率样本结合宽频扫描选项经常在求解器运行较少频率下产生宽频S参数Automatically chosen frequency samples in conjunction with the broadband frequency sweep option usually will yield the broadband S-parameters with a minimal number of frequency solver runs.一旦S参数扫描完成，求解器可以在S参数停下来的地方继续运行。例如为了计算另外的样本，监视器和进一步提高扫描精度。 Once the S-parameter sweep has finished, the solver can continue the S-parameter sweep just where it stopped, for instance in order to calculate additional samples, monitors, and further improve the sweep accuracy.（例子：自动取样下的宽频扫描）Example: A broadband frequency sweep with automatic sampling这个例子里全部频率范围里的7个频率以某种频率间隔计算得出。In this example seven frequency samples are calculated in a sub interval of the global frequency range. 请注意计算的频率不到20个样本，因为S参数的收敛判断标准早就达到。Please note that less than twenty samples are calculated, since the S-parameter convergence criterion is reached earlier. 在这个情况下，频域求解器参数对话框里的频率样本的数量表示一个更高的界限。In this case, the number of frequency samples in the Frequency Domain Solver Parameters dialog represents an upper limit. （例子：没有限制的自动取样下的宽频扫描）Example: A broadband frequency sweep with unlimited automatic sampling对于频率抽样，没有必要定义一个最大的样本。It is not necessary to define a maximum number of sample for the frequency sampling. 当样本频率的个数没有定义（左边空白处）如上图所示的时候，只要S参数的收敛判定满足的时候，求解器就停止计算另外的样本。When the number of samples is not defined (left blank) as shown above, the solver stops calculating additional samples as soon as the S-parameter sweep convergence criterion is satisfied. 结果如上所示，因为S参数扫描在计算7个频率样本后已经收敛。The results are the same as above, because the S-parameter sweep had converged after calculating seven frequency samples.例子：等间距抽样的频率扫描（Example: A broadband frequency sweep with equidistant sampling）在这个例子里，20哥频率样本在整个频率范围内等间距分布。分布间距是：In this example twenty frequency samples are distributed equidistantly in a sub interval of the global frequency range with a frequency spacing of当宽频扫描进行的时候，你将看到一条类似的曲线。You will see a quasi continuous curve when the broadband frequency sweep has been activated. 当另外的标记点在一维图特性对话框被检查的时候，频率样本可以看到，当查看S参数时，一维图特性对话框可以从内容目录里调用。The frequency samples are shown when Additional marks is为什么用is checked in the 1D plot properties dialog, which can be invoked from the context menu when viewing S-parameters. 如果你在频域求解器参数对话框里使扫描无效并且按下apply，已经计算出来的样本也可以显示，并且没有中间值。If you deactivate the sweep in the Frequency Domain Solver Parameters dialog and press Apply, the samples which actually have been calculated will be shown as well, without the intermediate values. 分布式计算和自适应取样（Distributed computing and adaptive sampling）如果分布式计算起作用，频率取样点的数量和位置可能不同。The number and position of frequency sampling points may differ if distributed computing is enabled. 这是因为在连续方式下，自适应取样不再完成。This is because the adaptive sampling is no more done in a sequential manner. 首先，如果四面体网格被选中，所有的均匀端口模式都可以计算并且连续网格可以在一台电脑上细化。First of all, if the tetrahedral mesh has been chosen, all the homogeneous port modes are calculated and eventually the sequential mesh refinement runs on one computer. 采用六面体网格的通用求解器按下面提到的处理，这种方法对四面体网格也适用。The general purpose solver with hexahedral mesh proceeds as mentioned hereafter, and this information applies to the tetrahedral mesh as well. 求解器采用剩下的确定的频率样本（通常是最大活最小或者中心频率和那些监视器自定义的频率），并把这些工作提交给分布计算系统。The solver takes all the remaining fixed frequency samples (usually minimum and maximum or center frequency, plus frequencies where monitors are defined) and submits those jobs to the distributed computing system. 系统决定有多少工作可以并行计算出。This system then decides how many of those jobs can be calculated in parallel. 限制的应用归因于许可证和可以利用的资源。Limitations apply due to the license, and available resources. 毕竟，如果自动频率扫描起作用，求解器决定把接下来的几个样本放在哪里，又一次提交给分布计算系统。Afterwards, if the automatic frequency sweep is enabled, the solver decides where to put the next few samples, and again submits those to the distributed computing system. 正如上面所提到的，和连续的频率扫描相比，这可以导致许多不同的样本，这就是求解器在电脑上运行的结果。As mentioned above, this can lead to a different number of samples compared to a sequential frequency sweep, that is when the solver runs on one computer. 通常更多的合适的点被计算，使用分布系统并行计算就越有效。Usually the more fix points need to be calculated, the more efficient is the parallel calculation using distributed computing. 无限阵列单元（Unit cells of infinite arrays）阵列单元和周期边界条件用来构建一个无限大阵列，它是由被称作“单元” 的许多相同的因子构成的。Unit cell and periodic boundary conditions are used to model an infinite array consisting of a identical copies of a so called unit cell. 对这些单元，由两个相反周期的边界平面的构成的场和一个复数因子是相关的，复数因子是由相移决定。For this unit cell, the fields for two opposite periodic boundary planes are related by a complex factor, which is determined by the phase shift. 对于频域计算，你可以选择性地通过输入一个在球坐标系里给定方向上的平面波的传播的固定的入射角来确定相移。 For frequency domain calculations, you may alternatively specify this phase shift by entering the constant angle of incidence corresponding to a plane wave propagating in the direction given in spherical coordinates. 看周期边界条件对话框帮助页可以获得更多的细节。See the Periodic Boundary Phase Shift dialog help page for details. 请注意在Z方向上，当单元的边界条件和开放边界条件结合在一起的时候，开放边界条件将通过Floquet端口自动实现，Floquet端口可以激励起一个平面波。Please note that when unit cell boundary conditions are combined with open boundary conditions in z-direction, the open boundaries will be automatically realized by a Floquet port, which allows to excite a plane wave. 更多的细节见“单元边界条件” 和“Floquet边界条件设置” 。Boundary Conditions - Unit Cell and Settings for Floquet Boundaries for details.我们也可以看到，在频域计算、周期边界下计算区间可以被开放边界条件或者被接触周期边界的波导端口所终止。（周期边界条件已经明确地创建，而不是为了单元边界定义一个开放的边界）Also note that the calculation domain with periodic boundaries can be terminated either by an open boundary condition or by a waveguide port touching the periodic boundary (which has to be created explicitly, rather than by defining an open boundary as for the unit cell boundary conditions) in Frequency Domain calculations: 通常，迭代求解器在周期的波导口被用来截取计算区间时，收敛速度是很快的。Usually, the iterative solvers convergence speed is higher if a periodic waveguide port is used to truncate the calculation domain. 更进一步，周期波导口可以用做平面波的激励和在波端口位置的更高次Floquet 模。 Furthermore, the periodic waveguide port can be used for the excitation of plane waves and higher order Floquet modes at the ports location. 怎样启动求解器（How to start the solver）在启动求解器之前，你必须设置好所有的必须设置。更多细节参阅频域求解器的设置。Before you start the solver you should make all necessary settings. See the Frequency Domain Solver Settings for details. 频域求解器可以从对话框频域求解器的参数来启动。The Frequency Domain solver can be started from the Frequency Domain Solver Parameters dialog box. 求解器的日志文件（Solver log file）在求解器完成后，你可以通过点击主菜单Results Solver Logfile看到日志文件。After the solver has finished you can view the log file by clicking Results Solver Logfile in the main menu. 日志文件包含借的设置、网格的概况、求解器结果和求解统计表。The log file contains information about solver settings, mesh summary, solver results and solver statistics.也可以看（See also）使用哪个求解器、频域求解器参数、频域求解器的取样、频域求解器的设置、频域求解器概览-谐振：快速S参数、频域求解器概览-谐振：S参数和场。Which Solver to Use, Frequency Domain Solver Parameters, Frequency Domain Solver Sampling, Frequency Domain Solver Settings, Frequency Domain Solver Overview - Resonant: Fast S-Parameter, Frequency Domain Solver Overview - Resonant: S-Parameter, fields二频域求解器的设置（Frequency Domain Solver Settings）在启动求解器之前，必须设置好下面的设置The following settings must be made before the solver can be started: Solve Set Units () 解设置单位（） Solve Background Material () 解背景材料（） Solve Frequency (): This frequency setting defines the maximum frequency range, which the automatic mesh generator takes into account to generate an accurate mesh.解频率（）：频率设置确定了频率范围的最大值，自动网格生成器根据频率的最大值生成一个精确的网格。 Solve Boundary Conditions () 解边界条件（） Solve Waveguide Ports () , Solve Discrete Ports () 解波端口（），离散端口（） Solve Lumped Elements () 解集总元件（） Solve Monitors (): If you define a monitor, the S-parameters for this frequency will be automatically cal