凝胶的介电常数怎么测量

> {quote：title = sercaspa写道：} {quote}>嗨，>>我一直在使用85070E同轴探头和E5072A矢量网络分析仪进行半固体材料的介电特性分析，特别是像明胶或果冻这样的凝胶。
我的问题是S~11~参数高度依赖于凝胶表面施加的压力，由于材料的变形，我前几天看到你的问题，但没有回应，因为我对此知之甚少。
但我知道日本开发阻抗分析仪的人在这些论坛上看起来并不活跃。
但我偶然发现了一个可能对你有帮助的参考资料。
它的应用笔记5966-1926E Agilent 4291B射频阻抗/材料分析仪第一部分介绍平行板方法，然后讨论粗糙表面。
我不知道是否有任何帮助，但值得一看。
DaveEdited：drkirkby于2015年12月12日下午9:22



     以下为原文

  > {quote:title=sercaspa wrote:}{quote}
> Hi,
> 
> I've been working with the 85070E coaxial probe and the E5072A vector network analyzer for dielectric characterization of semisolid materials, specifically gels like gelatin or jelly. My problem is that S ~11~ parameters are highly dependent on the applied pressure over the gel surface, due to the deformation of the material, 
I see your question the other day, but did not respond as I know very little about this. But I do know that the people in Japan developing the impedance analyzers don't appear very active on these forums. 
But I stumbled across a reference which might help you. It's application note 5966-1926E
Agilent 4291B RF Impedance / Material Analyzer The first section introduces the parallel plate method, then goes onto talk about rough surfaces. I don't know if it any help, but it might be worth a look. 

Dave

Edited by: drkirkby on Dec 12, 2015 9:22 PM

我在处理土壤样本时遇到了类似的问题。
我遵循尼尔森的论文中的建议，他建立了一个力量监测系统。
我建立了一个几乎相同的系统，以便我可以在样本上持续使用相同的力。
这不能回答正确力量的问题，只是如何保持一致。
我认为您将不得不尝试找到一个您认为可以接受的值，并将它用于每次测量。
在这方面，固体和液体更容易处理。
Nelson，Stuart O.，2012，技术说明：用于介电特性测量的同轴探针接触力监测，农业应用工程，v28，n1，pp149-152



     以下为原文

  I have dealt with a similar issue when using soil samples. I have followed the suggestions in the paper by Nelson where he built a force monitoring system. I built an almost identical system so that I can consistently use the same force on the sample. This doesn't answer the question of the correct force, just how to be consistent. I think you will have to experiment to find a value that you find acceptable and they use that for every measurement. Solids and liquids are much easier to deal with in this regard.



Nelson, Stuart O., 2012, Technical Note: Coaxial-Probe Contact-Force Monitoring for Dielectric Properties Measurement, Applied Engineering in Agriculture, v28, n1, pp149-152

附件

• Nelson_2012.pdf3.5 MB
  

非常感谢你们两位的答案！
关于drkirkby，平行板方法与开放式同轴方法完全不同，因为它首先是基于电容测量而最后是基于反射系数，所以我不知道是否有力
应用于样本以相同的方式影响。
我希望我可以尝试这种方法来比较，也许这是一种更好的方法来测量半固体。
关于ryanenorth，这是一个很好的解决方案，可确保可重复性并注意随时间的变化或类似样品之间的差异。
我担心施加的力的影响在不同的材料之间是不一样的。
此外，我会不确定样本的实际价值，这是我感兴趣的。
目前，我将继续使用探头施加最大可能的力而不会破坏它。
我相信这是空气去除的最佳近似值。



     以下为原文

  Thank you very much to you both for the answers!

With regard to drkirkby, the parallel plate method is quite different from the open-ended coaxial method, inasmuch as it the first is based on the capacitance measurement and the last is based on the reflection coefficient, so I don't know if the force applied to the sample affects in the same way. I wish I could try this method in order to compare, maybe it's a better method to measure semisolids.
With respect to ryanenorth, this is a nice solution for ensuring repeatability and noting changes over time or differences between similar samples. I fear that the influence of the applied force won't be the same between diferrent materials. Moreover, I would keep the uncertainty to the real value of the sample, which is of interest to me.
For the moment I will continue applying the maximum possible force with the probe without breaking it. I believe it's the best approximation due to the air removing.