同轴馈电长度的相关问题

   我们知道才CST微波工作室中端口区在纵向必须有至少三个网格是均匀的。所以在进行同轴馈电的时候馈线的长度是有要求的。在仿真中如果端口设置为如下情况则可能出错：

如果改成如下形式
    

则仿真会成功
难道只能这样吗?大家是怎么处理这个问题的，新手上路，希望大家都发表意见！

第一幅图应该是

According to your "first" figure, you should increase the mesh density to force the system generating at least three mesh lines at the waveguide port direction.

我们知道才CST微波工作室中端口区在纵向必须有至少三个网格是均匀的。所以在进行同轴馈电的时候馈线的长度是有要求的。?
同轴线设置一定长度就可以了，如果出现提示在纵向必须有没有三个网格是均匀的。增加同轴线长度就可以了

I guess he want to know if the simulation can be enabled with that short length coaxial feed line.

Yes,you get  it！  I  don't want such a long tail  attached  to my  design！ Thank you all for the answer！

You're welcome. Did you solve you problem? If yes, how did you do that, by increase the mesh density?

try to increase the mesh density manually. if increased by auto, it may not exist 3 cells in same dimension,without which it is not able to simulate.

Yes , I  increased   mesh density partly by  myselves  as showed below

Am  I  right?

Perfect！ And make sure you only refine the mesh lines at the desired direction.
Then what's the result? Has the error message gone?

Yes , From then ,I kown that  the  mesh Settings  is very important when we do some simulations.

Conguratulations！
Just read the Help files about "waveguide port overview" and the very bottom part it says:
Furthermore, for the realization of the waveguide port mode operator in the transient solver, it is necessary to have some equidistantly meshed region in front of the port, namely three mesh steps as shown in the picture on the right. This grid distribution in front of each waveguide port is automatically considered during the mesh generation and cannot be deactivated.

If the above mentioned condition is not automatically fulfilled by the mesh generation, it is useful to apply local mesh settings to achieve an equidistantly meshed region.

I'm  so sorry  that the "long tail" is necessary.But by do so,the error has gone.  Thank you！

You  have teld me a secret that if I want to have a good comprehension of the software,  the "help contents" is really a good meterial.Thank you！

太聪明了，我就只会增加同轴长度。

谢谢 学习了 我想问一下的是若要求输入阻抗是50欧，则这个同轴线的尺寸之间有一个什么样的关系了?包括那个接地板

从哪里的输入阻抗?
建议熟悉传输线理论，建议阅读《微波工程》里同轴线的章节。

可以利用CST的Macros內的Calculate裡的Calculate analytical line Impedance做調整計算

小d=同軸芯線
大D=介質
外圈(紅色)=接地
在裡面有個EPS的空格，是用來填介質的介電係數

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