CST学习材料之CST激励概述

CST 学习材料 Excitation Source Overview 激励源概述 CST MICROWAVE STUDIO® offers several different excitation sources, depending on the specific application and structure types. In the following a short overview list is given, please refer to the respective overview pages to learn more about the corresponding excitation source type. CST 微波工作室®提供了多种不同的激励源，这取决于具体应用和结构类型。下面 给出了一个简短的概述，请参阅有关的概述页，以了解相应的激励源类型。  端口 Usually used for S-Parameter calculations 通常用于 S 参数的计算 The S-matrix describes the transmission of electromagnetic field energy between different ports of a structure. These ports, especially their name and location, need to be defined in CST MICROWAVE STUDIO®. Two different kinds of ports exist: Waveguide Ports and Discrete Ports. You must first decide which port to use at a particular location. The type of the ports may vary within a structure, of course. S -矩阵描述了一个结构不同端口之间电磁场能量的传输。这些端口的名字和位 置需要在 CST 微波工作室®中定义。存在两种不同类型的端口：波导端口和离 散端口。你必须首先确定在特定位置处该使用什么端口，当然，结构内部端口 的类型可能会不同。 - Discrete Ports(lumped elements) CST 学习材料 Discrete ports are available as S-Parameter, voltage or current port. They are mainly used to simulate lumped element sources inside the calculation domain and can be used for TEM-like modes. Input: Knowledge of TEM-mode, line impedance (voltage or current respectively) Output: Voltage or current 离散端口（集总元件） 离散端口可用于 S 参数, 电压或电流端口。其主要用于计算域内部的仿真集总 元件源，同时可用于类同 TEM 的模式。 输入：Knowledge of TEM-mode，线路阻抗（电压或电流） 输出：电压或电流 - Waveguide Ports- Multipin Ports(2D eigenmode solver) Waveguide ports are used to simulate an infinitely long waveguide, e.g. a rectangular waveguide, a coaxial cable or a microstrip line. They deliver a better match to the mode pattern as well as higher accuracy in S-Parameters. Input: Area for eigenmode solution Output: E and H-pattern, line and wave impedance, propagation constant (beta, alpha) 波导端口，多芯端口（二维本征模求解器） 波导端口用于仿真无限长的波导，如矩形波导，同轴电缆或 微带线。它能提供一个更好的匹配模式以及提供 S -参数更高 的精度 输入：本征模式解决 方案 气瓶 现场处置方案 .pdf气瓶 现场处置方案 .doc见习基地管理方案.doc关于群访事件的化解方案建筑工地扬尘治理专项方案下载 的区域 输出：E 和 H 场分布情况，线阻抗，波阻抗，传播常数（β，α） CST 学习材料  Field Sources Imprint of field distributions  场源 场分布说明 - Plane Waves Excitation of linear, circular or elliptical plane waves. 平面波 线性，圆形及椭圆形平面波的激发 - Farfield Sources Import of a farfield monitor file calculated with CST MICROWAVE STUDIO® 远场源 导入 CST 微波工作室®计算的远场监视器文件 -Nearfield Sources Import of near field source data calculated by CST MICROWAVE STUDIO®, CST CABLE STUDIO®, or CST PCB STUDIO®. Also available is the import of Sigrity® NFD radiation data. 近场源 导入 CST MICROWAVE STUDIO®, CST CABLE STUDIO®, or CST PCB STUDIO®计算的近场源数据。也可导入 Sigrity® NFD 的辐射数据 Waveguide Port Overview 波导端口概况 Waveguide ports represent a special kind of boundary condition of the calculation domain, enabling the stimulation as well as the absorption of energy. This kind of port simulates an infinitely long waveguide connected to the structure. The waveguide modes travel out of the structure toward the boundary planes thus leaving the computation domain with very low levels of reflections. 波导端口是一种特殊种类的解算域边界条件，它可以刺激能量的吸收。这种端口模 CST 学习材料 拟无限长波导连接到结构上。波导的模式可以从边界面传播出去，因此使得计算域 的反射很低。 Very low reflections can be achieved when the waveguide mode patterns in the port match perfectly with the mode patterns from the waveguides inside the structure. CST MICROWAVE STUDIO® uses a 2D eigenmode solver to calculate the waveguide port modes. This procedure can provide very low levels of reflection below -100dB in some cases. 当端口的波导模式与结构内部的波导模式很好的匹配时也可以获得很低的反射。 CST MICROWAVE STUDIO®用二维本征求解器计算波导端口模式。这个过程在某 些例子中能够提供低于-100 dB 的反射率。 In general, the definition of a waveguide port requires enclosing the entire field filled domain in the cross section of the transmission line with the port area. The eigenmode solver can then calculate the exact port modes within these boundaries. The number of modes to be considered in the solver calculation can be defined in the waveguide port dialog. The strategies to properly define waveguide ports depend a bit on the type of the transmission line. In the following we focus on the most commonly used applications. 总的来说，波导端口的定义需要包括端口区传输线截面处的全部场域。使用这些边 界条件，本征求解器就可以计算准确的端口模式。求解器计算所需要考虑的模式数 CST 学习材料 可以在波导端口对话框定义。适当波导端口定义的策略取决于的传输线类型。在下 面，我们主要专注于最常用的应用。 Please note that the input signal of an excited waveguide port is normalized to 1 sqrt(Watt) peak power. 请注意，波导端口的激励输入信号的峰值功率被归一化到 1 瓦。 内容 空波导 创建端口 端口模式 同轴波导 创建端口 端口模式 微带线 端口模式/端口规格 创建端口 共面线 端口模式/端口规格 创建端口 非均匀波导端口（特别处理） 微带线/共面线（QTEM） 介质加载波导（非 QTEM 模式） 多引脚波导端口 CST 学习材料 均匀多引脚端口 非均匀多引脚端口 周期波导端口 基本信息 波导端口的损耗 阻抗定义 模式校准 模式极化 六面体的波导端口在网格中的视图 Empty Waveguides 空波导 The most frequently used waveguide type of this category is the rectangular waveguide shown below: 这一种波导最常用类型的是矩形波导，如下所示： Port Creation  创建端口 CST 学习材料 The port assignment for this type of waveguide is quite simple. However, it is important to make sure that the port covers the entire waveguide cross-section. The easiest way to define a port’s face is to pick structure elements such as points / edges / faces before opening the port definition dialog box. The port dimensions will then automatically adjust to the bounding box of the picked elements. 这种波导端口分配很简单。但是，确保端口覆盖整个横截面很重要。定义端面 最简单的方式是在打开端口定义对话框之前就选好点/棱/面等元素。这端口规 格会自动校准到所选元素的边框。 If the interior of the waveguide is modeled by a dielectric material block, you can simply pick the end face of the waveguide as shown in the picture below: 如果波导内部是以绝缘材料为模板，你就可以简单的选择波导端面来定义端 口，如下图所示： The bounding box of the picked end face will then exactly define the dimension of the port. 所选端面的边框将会确切的限定端口的尺寸。 When the background material is not made of PEC material, it is often required to model the wall of the waveguide, too. For a construction like the one shown in the first picture above, the end face of the rectangular waveguide has not been modeled directly. 当背景材料不是由 PEC（导体） CST 学习材料 材料组成时，则它经常要求对波导壁进行建模，如上面第一个图片的结构体， 这个矩形波导端面并没有马上建模。 We therefore recommend to pick the edges on the circumference of the waveguide or to pick two opposite points on the corners: 因此，我们建议选择波导周边的边界或选择转角的两个相反的点。 In both cases, the bounding box of the picked elements will be large enough to cover the entire field filled cross-section of the waveguide. The resulting port definition will then look as follows: 在这两种情况下，所选基元的边框将足够大到能覆盖整个域来填充波导横截 面，端口定义的结果如下图所示：  Port Modes  端口模式 CST MICROWAVE STUDIO® solvers generally allow using more than just the fundamental mode in the waveguide port. This becomes especially important when higher order modes need to be taken into account. CST CST 学习材料 MICROWAVE STUDIO®求解器允许波导端口不只是使用用基模。考虑到用更 高阶模式时这就显得特别重要。 In the pictures below, the first three modes of an empty waveguide are shown, sorted by their respective cutoff frequency. The number of propagating modes vary due to the chosen frequency range. As a rule, the number of modes to be considered at a waveguide port should at least be the number of propagating modes, because unconsidered modes will be reflected by the port operator. 下面的一些图片显示了空波导的头三种模式，三种模式是按各自的截止频率分 类的。所选的频率范围不同，传播模式数量也将会变化。通常，波导端口需要 考虑的模式数量至少应该为传播模式的数量，因为未被考虑过的模式将被端口 解算器所反射。 If an evanescent port mode result is selected, a box will appear visualizing the distance from the port where the port mode has decayed by -40dB: 如果瞬态端口模式结果被选出。模型将会在端口到端口模式衰减到-40dB 的一 段距离可视化。 CST 学习材料 Multiple waveguide modes can convert energy into each other at the structure’s discontinuities. Due to these phenomena, the S-parameters of the propagating modes can also be affected by the evanescent modes. Therefore a certain number of evanescent modes needs to be taken into account. We recommend that the number of modes used for the simulation be chosen such that the -40dB distance of the last considered mode is shorter than the distance to the next discontinuity. This setting will ensure that all modes not considered for the simulation will make only very small contributions to the mode conversion. 多引脚端口模式可以在结构的间断点之间进行能量交换。由于这些现象的存 在，使得瞬态模式能够影响传播模式的 s 参数。因此，需要考虑到瞬态模式的 确定数值。我们推荐选择的用来模拟的模式数要满足最后模式的-40dB 的距离 比到下一个间断点的距离更短。这样的设置将确保所有没考虑到的模式不会对 模式转换产生影响。  Mode Polarization  模式的极化 In the case of quadratic or circular waveguides, the mode polarization is an issue. Please find a detailed discussion in the section Mode Polarization. 在二次波导和圆形波导情况下，模式的极化是个问题。详情请参阅 Mode Polarization。 Coaxial Waveguides 同轴波导 这种波导最常用到的类型是如下图所示的同轴线： CST 学习材料  Port Creation  端口创建 The port assignment for this type of waveguide is very simple. However, it is important to make sure that the port covers the entire cross-section of the coaxial cable. The easiest way to define the port face is to pick structure elements such as points / edges / faces before opening the port definition dialog box. The port dimensions will then automatically adjust to the bounding box of the picked elements. 这种波导类型端口分配非常简单。但是，确保端口覆盖同轴 线的横截面很重要。定义端面最容易的方式是在打开端口定义对话框之前就选 择好结构元素如点/棱/面。端口大小会自动校准到所选结构源的边框。 In most cases, the dielectric part of the coaxial cable will be modeled with a solid cylinder. If this is the case, simply pick the end face of the dielectric as shown below: 在大多数情况下，同轴电缆的介质部分将会被模仿成一个圆柱体。在这种情况 下，很容易选择介质的端面正如下图所示： The bounding box of the picked end face will then define the dimension of the port. Note that the waveguide port is still shown as a rectangular face. However, the computation of the waveguide mode will be automatically restricted to the interior of the coaxial cable. 所选端面的边框将定义为端口的规格大小。注意波导端口仍然 显示成矩形面。但是，波导模式的计算将自动限制在同轴电缆的内部。 If the end face of the dielectric can not be picked for some reason, you can also pick edges or points on the circumference of the coaxial cable as described for the empty waveguides. CST 学习材料 如果因为某些原因介质端面不能被选择，你仍然可以在同轴电缆的周边选择棱边和点。就如描绘空波导 一样。  Port Modes  波导模式 In most cases, you will need to consider the fundamental mode of the coaxial cable so that you don’t need to worry about the number of modes for the port. The mode is automatically polarized so that the electric fields point from the inner conductor to the outer conductor as shown in the following picture: 在大多数情况下，只需要考虑同轴电缆的基模，所以你不必担心端口模式数。模式将会自动极化使得电 场从导体内部指向外部，如下所示： Microstrip Lines 微带线 The microstrip line is one of the most commonly used transmission lines for high frequency devices. 微带线是用于高频设备传输中最常用的传输线。 Unfortunately, this line type is relatively complex from an electromagnetic point of view. Therefore a few things need to be considered when defining ports for this type of structure. 不幸的是，从电磁方面的角度讲这种线是 十分复杂的。因此，在定义这种类型结构的端口时要考虑到某些方面。 This type of structure requires modeling the air above the microstrip line, too. The easiest way to achieve this is to specify an extension in the Background Material dialog box. 这种类型结构需要在微带线上面对空气进行建模。要达到此目的最简单的 方法 快递客服问题件处理详细方法山木方法pdf计算方法pdf华与华方法下载八字理论方法下载 是在背景材料对话框指定 这种扩展材料。 CST 学习材料  端口模式/端口尺寸  Port Modes / Port Dimensions In general, the size of the port is a very important consideration. On one hand, the port needs to be large enough to enclose the significant part of the microstrip line’s fundamental quasi-TEM mode. On the other hand, the port size should not be chosen unnecessarily large because this may cause higher order waveguide modes to propagate in the port. 通常，端口大小是要考虑的一个重要方面。一方面，端口需要足够大来密封微带线 的本征准 TEM 模式的有效部分。另一方面，端口尺寸也不要选择太大，因为这有可能导致高阶波导模式 在端口传播。 The following pictures show the fundamental microstrip line mode and higher order mode. 下面的图片展示了微带线本征模式和更高阶模式。 本征模式 更高阶模式 The higher order modes of the microstrip line are very similar to modes in rectangular waveguides. This behavior can be explained by an enclosure that is automatically added along the port’s circumference for the port mode calculation. The boundary conditions at the port’s edges will adopt the settings from the 3D model. In case of an ”open” boundary in the 3D model, a ”magnetic” port boundary will be used. This enclosure around the port causes the port to behave like a rectangular waveguide and thus is responsible for the particular pattern of the higher order modes. 微带线的高 阶模式同矩形波导模式很相近。在端口模式计算中外壳会自动加长端口的周长能够解释这种特点。端口边缘 的边界条件会采取 3D 模式这种设置。在 3D 模式中假如边界为“open”，那么“magnetic”端口边界将会被应 用。端口周围的界限使端口的特点像矩形波导一样，因此，同高阶模式的特殊形态有关。 The larger the port, the lower the cut-off frequency of these modes. Since the higher order modes are somewhat artificial, they should not be considered in the simulation. Therefore, the port size should be chosen small enough that the higher order modes can not propagate, and only one (fundamental) mode should be chosen at the port. 端口越大，这些模式的截止频率就越低。由于高阶模式从某种方面来说是假的，所以在仿真中 不应该考虑它们。因此，端口尺寸应该尽量选择得小而不让高阶模式传播，在端口中应该只能选择本征 模式这一种模式。 If higher order microstrip line modes become propagating, this normally results in very slow energy decays in the transient simulations and sharp spikes in the frequency domain simulation results, respectively. On the other hand, choosing a port size too small will cause degradation of the S-parameter’s accuracy or even instabilities of the transient solver. If you experience an unexpected behavior like this, check the size of the ports. 假如高阶微 带线模式传播的话，通常会导致在瞬态模拟中能量衰减的很慢，尤其在频域模拟的结果中会出现剑锋现 象。另一方面，选择的端口尺寸太小会使 s 参数的精确性降低，甚至会使瞬态求解器工作不稳定。如果 根据你的经验，觉得仿真结果出乎意料，那么就核对一下端口的尺寸大小。 As a rule, the size of the port should be chosen according to the following picture: 作为一种规则，端口选择的尺寸应该同下图的一致: CST 学习材料 Ideally you would make the port 10 times as wide as the width of the microstrip line, but this may be reduced to around 6 times the microstrip line width in case of geometrical constraints. 理想情况下，你应该选择端口宽度是微带线宽度的 10倍，但是如果有几何约束也可以降低到微带线宽度 的 6 倍左右。（很重要！）  Port Creation  端口创建 One way to define the port for this type of structure is to enter all its coordinates numerically. However, since this is a cumbersome solution, we will illustrate how ports for microstrip lines can be defined based on picked geometry. 定义这种结构类型端口的方法是键入它的所有数字坐标。但是，由于这是一种麻烦的解法，我 们将阐明基于所选的几何图形来定义微带线的哪种端口。 You can pick the entire end face of the microstrip line or pick the edge of the end face which is located on the surface of the dielectric substrate. The following pictures illustrate these options: 你可以选择微带线的整个端面或者选择介电基板表面的端面边缘。下面的图片将说明这些操作： 选择端面 选择底部边缘（在基板上） After picking the geometry, you can open the port definition dialog box (Solve Waveguide Ports). In this dialog box, simply specify an extension of the port around the picked geometry by entering the distances in the corresponding entry fields. In case of a single picked line, you also need to set the port’s normal direction and orientation since it cannot be automatically derived from the picked geometry. 在选择了几何图形后，你可以打开端口定义对话框（solve 波导端口）。在这个对话框中，在相应的输 入栏中键入一定距离就可以很简单的指定所选几何图形端口的范围。在单一选线的情况下，你仍然需要 设置端口的 标准 excel标准偏差excel标准偏差函数exl标准差函数国标检验抽样标准表免费下载红头文件格式标准下载 方向和方位因为它不能从所选几何图形中自动导出。 CST 学习材料 You need an extension space of ideally 4.5 times the width of the microstrip line (here 25) at each side of the microstrip line. Furthermore, you should specify a distance of 4 times the substrate height (here 25) above the strip line. 在微带线的每个面你需要一个理想的扩展空间，这空间是微带线宽度（这里是 25）的 4.5 倍。此外，你 应该指定在带线上方的距离四倍于基板的高度（这里是 25）。 Note: Make sure to enter exactly the height of the substrate for the port extension below the microstrip line or you will introduce some unwanted additional space between the substrate and the ground metallization, or the port may not be connected to ground at all. We therefore recommend defining a parameter for the substrate’s height (e.g. substrate_height). This parameter can then be used for specifying the bottom extension as shown above. 注意：请确保准确输入在微带线下面用于端口扩展的基板高度，确保准确输入你将引入的在基板 和金属面的一些多余的额外空间，或者一些没同地面相连的端口。因此，我们建议将基板的高度参量化 （例如：用 substrate_height 来表示基板的高度）。这个参数可以用来说明底部的扩展，如图所示： The explanations given above mainly refer to the unshielded microstrip lines. When a shielded microstrip problem needs to be simulated, the port can usually be chosen in such a way that it covers the entire dimension of the structure. The physical CST 学习材料 problem of unwanted box resonances appears much earlier in these cases than the artificial problem of unwanted propagating modes so that you do not need to worry about the latter here. 上面给出的解释主要涉及的是非屏蔽的微带线。当一个屏蔽的微带问题需要被模拟时，通常选择的端口 它要覆盖整个结构体的大小。在这些情况下，多余的共鸣箱这种物理问题比假想的多余的传播模式问题 更容易出现，因此在这里不需要担心后者。 The picture below shows the assignment of ports for a shielded structure with perfect electric conducting walls at each side: 下 面 的 图 片 显 示 的 是 每 边 都 是 完 美 导 电 墙 的 屏 蔽 结 构 体 的 端 口 分 配 ： The easiest way to define a waveguide port covering the entire boundary face of the computation domain is to use the Full plane option in the port definition dialog box rather than using previously picked elements. 定义覆盖 整个计算域边界面的波导端口最简单的方法是在端口定义对话框中选择满平面（full plane）选项而不 用先前选的项。 Some structures require more than one microstrip line being located at the same boundary of the computation domain. In general, you should try to avoid this situation if possible because it adds complexity to the port assignment. 有些结构需要一个以上微带线位于计算域的同一边界上。通常，你应该尽量避免出现这些情 况因为它会增加端口分配的复杂性。 However, if the microstrip lines are far enough away from each other that the interaction of fields is negligible, then ports can be assigned in the same way as described above using the same port size rule. An example for a structure like this is shown in the picture below: 可是，如果微带线之间的距离足够远，那么他们场的相互作用就可以忽略不计，此时，他们同样可以用 上面描述的端口大小规则来分配端口。像这样的结构的例子如下图所示： If the lines get even closer, then they no longer work as two independent microstrip lines since the mode fields interact with each other and the waveguide becomes a multipin waveguide. Please refer to the Multipin Port Overview for this type of waveguide. 如果线越靠近，则他们就不再像两个独立的微带线一样工作了，因为 这种模式的场相互作用，那么波导就成为了多引脚波导了。这种类型的波导请参阅多引脚波导概述。 Another important aspect in the simulation of microstrip lines is that the mode pattern is frequency dependent (unlike the mode patterns in empty guides or coaxial lines). 在微带线模拟中另一个重要的方面是模式形态 CST 学习材料 的频率相关性（这和空波导或同轴线的模式形态不同）。 The frequency domain solvers automatically recalculate the mode patterns for every frequency point so that this frequency dependent behavior does not cause a difficulty for the analysis. 频域求解器自动重新计算每个频 点的模式形态，使这种频率依赖特征不会导致分析难度的增加。 In contrast, the time domain solver uses the same mode pattern for the entire frequency band which may cause port mode mismatches at frequencies other than the mode calculation frequency. The error increases with increasing distance to the mode calculation frequency. 另一方面，时域求解器在整个频带用同样的模式形 态，这可能导致端口模式同频率不匹配，这不同于模式计算频率。随着距离的增加模式计算频率的误差 也会加大。 By default, the transient solver computes the mode pattern at the center frequency of the frequency band, but this behavior can be changed by specifying the Mode calculation frequency in the solver specials dialog box on the Waveguide page. 默认的频域求解器在频带的中心频率计算模式形态，但是在波导页的求解器特别对话 框中指定模式计算频率（Mode calculation frequency）项就可以改变这种特性。 Despite this small mismatch at the ports, broadband simulation results will still be sufficiently accurate in most cases. However, very high accuracy requirements or very large bandwidths may require you to activate the inhomogeneous port accuracy enhancement option in the transient solver dialog. box. This feature will improve the accuracy of the S-parameters but on the other hand will slow down the simulation. 在端口中尽管有一些很小的不匹配，但是在大多数情况下带宽模拟结果还是十分精确的。但是，如果需 要非常高的精确度或者极大的带宽的话，这就要求在时域求解器对话框中激活非均匀端口精度增强 （inhomogeneous port accuracy enhancement）选项。这种特征将会改善 s 参数的精确性但是另一方面会降 低模拟的速度。 Coplanar Lines 共面线 The coplanar l