介电常数VS频率？？

不要命的男人 · 发表于 2006-2-6 16:56:00

大家：介电常数和频率有关系吗？？？谢谢了

easychen · 发表于 2006-2-6 20:36:00

of course

不要命的男人 · 发表于 2006-2-7 09:45:00

是绝对没有关系还是有一点关系但可以忽略如果有关系是怎么的关系？？谢谢！

easychen · 发表于 2006-2-13 08:46:00

Operating frequency has great impact on dielectric constant of a dielectric material.
When measuring In low frequency, dielectric constant of a diecetric is easily above 2000.But in microwave band,exceeding 100 is very difficult for the same dielectric material .So you can't ignore it.
The relation between freq and dielectric constant is not simple.It can't be described by a simple formula by now.The measurement may be the best way to describe it.
+5 RD币

[此贴子已经被feel于2006-2-14 23:25:44编辑过]

不要命的男人 · 发表于 2006-2-17 09:27:00

那么传输线的特性阻抗和信号的频率也由很大的关系了？？？

neil1981 · 发表于 2006-2-17 10:18:00

特征阻抗与基片厚度介电常数和微带线宽度有关。与频率无关

easychen · 发表于 2006-2-17 11:57:00

Characteristic Impedance of transmission line is impacted by dielcetric constant of dielectric.So characteristic impedance depends on the frequency.Because the variation of dielcetric constant in rf and microwave band is not so obvious.In enginneering application we ignore dielcetric constant's variation.My example in my reply was wrong.It is not for the same materials.But the dielectric constant's variation on frenquency is absolutely right.

lzh141 · 发表于 2006-2-17 12:21:00

部分介质板如FR-4介电常数会随工作频率有变化

chunhuic · 发表于 2006-2-18 20:36:00

介电常在不同频率上略有些不同，我有一份厂家测度报告，你有兴趣的话可以发给你。

不要命的男人 · 发表于 2006-2-21 12:25:00

chunhuic： 谢谢啊 <a href="mailtlifelesssexpot@163.com" target="_blank" >lifelesssexpot@163.com</A>

wjg980366 · 发表于 2006-2-21 20:48:00

和温度，频率都有关系．

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[讨论] 介电常数VS频率？？