对于开放式校准标准，可以有负偏移和电容吗？

首先，祝大家圣诞快乐。
我花了一些圣诞节来讨论我的8720D VNA - 它是由我个人拥有的，因此在我的家里，所以它不像它看起来那么不干净！
我感兴趣的是看一个未连接的公N连接器是否可以用作“开放式”校准设备，如果是，那么哪个参数最好。
好吧，我知道它可以完成，因为FieldFox系列上的QuickCal可以做到这一点，但当然我需要参数进入VNA。
如果他们是安捷伦的老手，我也不会感到惊讶。
首先使用适当的'N'校准套件（85032B）进行校准后，我注意到以下情况。
1）令我惊讶的是，开放式N似乎不是电容性的，因为我认为由于边缘电容。
相反，它似乎是归纳的。
是否能够通过值为2的电容器来表示电感。中心导体位于参考平面下方约1 mm。
鉴于真空中的光速为299792458 m / s，这表明输入的偏移应为-0.001 / 299792458 = -3.335 ps。
那有意义吗？
也许值得说明偏移几ps - 使其更负面，因此可以将电容作为正值输入。
我不确定这是否比使用负电容更好或更差。
对于它的价值，我最初尝试通过曲线拟合找到C0，C1，C2和C3的合理值并不太成功，但我怀疑它有更多的时间可能是可行的。
如果有人试过这个，或者知道参考文献，我会感兴趣的。
你可能觉得我很生气，但现在是圣诞节，所以我喝了一两杯啤酒！
有了这一切，一切顺利。
我要去爱尔兰咖啡吧！
（这在英国很受欢迎 - 对美国不太确定。我猜你可以用杰克丹尼尔威士忌制作它。）如果我说实话，我用一种廉价的苏格兰威士忌制作“爱尔兰咖啡”。
我认为将更昂贵的爱尔兰威士忌放入咖啡中是不合理的。
戴夫

以上来自于谷歌翻译

   以下为原文

  First of all, merry Christmas to everyone.

I've spent some of Christmas day messing around with my 8720D VNA - it is personally owned by me, hence in my home, so it was not quite as unsociable as it might appear!

I was interested in see if an unconnected male N connector could be used as an "open" calibration device, and if so what parameters would be best. Well, I know it can be done, as the QuickCal on the FieldFox range do this, but of course I needed the parameters to enter into the VNA. and I would not be surprised if they are proprietry to Agilent.

I noticed the following, after first calibrating with a proper 'N' calibration kit (85032B).

1) Much to my surprise, the open-N does not appear to be capacitive, as I would have thought due to the fringing capacitance. Instead, it appears inductive. Would it make sence to represent an inductance by capacitor of a value < 0 ? I found it is possible to enter negative values for all value C0, C1, C2 and C3. .

2) The centre conductor sits below the reference plane by about 1 mm. Given the velocity of light in a vacuum is 299792458 m/s, that would suggest the offset to be entered should be -0.001/299792458 = -3.335 ps. Does that make sense?

Perhaps it is worth lying about the offset by a few ps - making it even more negative so it is possible to enter the capacitance as a positive value. I'm not sure if that would be better or worst than having negative capacitors.

For what it is worth, my initial attempts to find sensible values for C0, C1, C2 and C3 by curve fitting were not too successful, but I suspect with more time it might be workabe. If anyone has ever tried this, or knows of a reference, I'd be interested.

You probably think I am mad, but it is Christmas day, so I have had a beer or two!

With that, all the best. I'm going to have an Irish Coffee! (That's quite popular in the UK - not so sure about the USA. I guess you could make it with Jack Daniels whisky.) If I'm honest, I make an "Irish Coffee" using a cheapish Scotish whisky. I think putting the more expensive Irish whisky in a coffee is not justified.

Dave

李德鹏

2019-4-28 11:44:43

我最初写道：“我真的没有看到开路标准在最初开始跟踪时看起来像是电容性物质。但有可能的是，你的开放标准物理长度相对于你的工作频率是如此之长
这可能会超过180度标记。这是可能的。除此之外，我看不出开放标准（设计为“开放标准”）将如何看似归纳。“
但我重新阅读了你的帖子，看到你在校准后正在查看你的数据。
现在，我可以看到为什么你看到你看到的痕迹。
您的NA可能已损坏，或输入的校准输入不正确，或者测试系统中的连接存在物理错误，或者您的开放式标准连接器损坏。
或许你喝了太多啤酒！
大声笑！
顺便说一下，圣诞快乐，新年快乐！
编辑：SOLT_guy于2012年12月30日上午7:17编辑：SOLT_guy于2012年12月30日上午7:21编辑：SOLT_guy于2012年12月30日上午7:45编辑：SOLT_guy于2012年12月30日7：
47 AMEdited：SOLT_guy于2012年12月30日上午7:54

以上来自于谷歌翻译

   以下为原文

  I initially wrote this:

"I don't really see how physically an open standard can appear to be anything but capacitive when the trace initially commences.
It may be possible, that your open standard is so long in physical length relative to your working frequency that it might cross the 180 degree marker.   This is possible.   Other than that, I can't see how an open standard (which is designed to be an "open standard") will appear to be inductive."

But I re-read your post and saw that you were looking at your data after calibration.      Now, I can see why you saw the trace that you saw.

It may be possible that your NA is broken, or incorrect calibration inputs were input, or there is something physically wrong with the connections in your test system, or your open standard connector is broken.   Or maybe you had one too many beers! LOL!

By the way, MERRY CHRISTMAS and have a HAPPY NEW YEAR!!!

Edited by: SOLT_guy on Dec 30, 2012 7:17 AM

Edited by: SOLT_guy on Dec 30, 2012 7:21 AM

Edited by: SOLT_guy on Dec 30, 2012 7:45 AM

Edited by: SOLT_guy on Dec 30, 2012 7:47 AM

Edited by: SOLT_guy on Dec 30, 2012 7:54 AM

李德鹏

2019-4-28 11:56:25

引用: szzjfyp 发表于 2019-4-28 20:58
我最初写道：“我真的没有看到开路标准在最初开始跟踪时看起来像是电容性物质。但有可能的是，你的开放标准物理长度相对于你的工作频率是如此之长
这可能会超过180度标记。这是可能的。除此之外，我看不出开放标准（设计为“开放标准”）将如何看似归纳。“
但我重新阅读了你的帖子，看到你在校准后正在查看你的数据。

这个问题很有意思：“2）中心导体位于参考平面下方约1 mm。假设真空中的光速为299792458 m / s，则表明输入的偏移应为-0.001 / 299792458
= -3.335 ps。这有意义吗？“
有人可以给我们一些反馈吗？

以上来自于谷歌翻译

以下为原文

This question is of interest:

"2) The centre conductor sits below the reference plane by about 1 mm. Given the velocity of light in a vacuum is 299792458 m/s, that would suggest the offset to be entered should be -0.001/299792458 = -3.335 ps. Does that make sense?"

Can someone offer us a little feedback?

李青

2019-4-28 12:11:56

在实践中，使用端口扩展，并将端口扩展-3.335 ps仍然显示归纳行为。
-6.5 ps的端口扩展似乎使N插头看起来像一个点，参数随频率没有变化。
鉴于有肯定会被边缘电容，并采取猜测这将是大约120法郎，然后用端口扩展播放显示有关-12.8 PS的偏移需要得到一个开放的N型连接器是某处的电容值
接近现实。
我认为N连接器的另一个问题是，除非公引脚的直径增加，否则最后几毫米不是50欧姆的传输线，而是更高的阻抗，因为未配合的公引脚非常薄。
这可能是我的VNA的一个问题。
如果你有一个N校准套件，我有兴趣看看你发现的是一个开放的公N连接器的属性。
也许你也会看到它似乎是归纳的。
顺便说一下，根据我的VNA，一个开放的N型连接器显示出相当大的电容（几百fF），不像它的男性对应物，它看起来是感应式的。
Dave编辑：drkirkby于2012年12月30日8:16 PM编辑：drkirkby于2012年12月30日下午8:34

以上来自于谷歌翻译

以下为原文

In practice, using port extensions, and extending the ports by -3.335 ps still shows inductive behaviour. A port extension of -6.5 ps appears to make an N plug look like a spot, with no change in parameters with frequency.

Given there is certainly going to be fringing capacitance, and taking a guess it will be around 120 fF, then playing with the port extensions shows an offset of about -12.8 ps is needed to get a capacitance value of an open N connector which is somewhere near realistic.

I think the other issue with the N connector is that unless the diameter of the male pin is increased, the last few mm are not a 50 Ohm transmission line, but a somewhat higher impedance, as the unmated male pin is quite thin.

It could be an issue with my VNA. If you have an N calibration kit, I'd be interested to see what you find are the properties of an open male N connector. Perhaps you too will see that it appears inductive.

BTW, according to my VNA, an open female N connector shows a fair large capacitance (several hundred fF), unlike it its male counterpart, which appears inductive.

Dave

Edited by: drkirkby on Dec 30, 2012 8:16 PM

Edited by: drkirkby on Dec 30, 2012 8:34 PM

李德鹏

2019-4-28 12:25:11

亲爱的柯比博士;
我无法评论您的具体情况，因为我无法测量您的特定校准套件的参数。
我只能假设你为什么看到你所看到的。
我不知道你是如何进行测量的。
我认为最好等一位安捷伦工程师向我们提供一些反馈意见。
让我们拭目以待安捷伦工程师说些什么。
顺便说一句，新年快乐！
编辑：SOLT_guy于2013年1月1日上午8:22编辑：SOLT_guy于2013年1月1日上午8:29

以上来自于谷歌翻译

   以下为原文

  Dear Dr. Kirby;

      I can't comment on your particular situation because I can't measure the parameters of your particular cal kit.    I can only hypothesize why you see what you see.

     I have no idea how you made your measurements.

     I think it would be best to wait for an Agilent engineer to offer us some feedback.

     Let's wait and see what an Agilent engineer has to say.

     By the way, HAPPY NEW YEAR!!!

Edited by: SOLT_guy on Jan 1, 2013 8:22 AM

Edited by: SOLT_guy on Jan 1, 2013 8:29 AM

李青

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