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李青

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[问答]

如何使用安捷伦85033E 3.5毫米校准套件测量SMA设备?

我有一台HP 8720D VNA和Agilent 85033E校准套件,想测量一台SMA母设备。
该设备实际上是SMA短路,我想找到参考平面和短路之间的距离。
但我得到的结果看起来并不太好,我怀疑它是由于SMA与3.5毫米之间的不匹配,但我可能错了。
但我不知道如何最好地纠正这个问题,或者至少减少它的影响。
如果我从85033E校准套件中取出* 3.5 mm母短标准*,并应用等于短路偏移延迟的端口扩展,则在史密斯圆图上,设备看起来像左边的点。
毫不奇怪,如果我现在用* SMA母短*替换3.5毫米短片,我无法找到任何端口延伸,史密斯圆图在左边显示一个点。
史密斯圆图视图(手工编辑,因为我的软件没有非常清楚地显示它),显示端口扩展为25.854 ps的视图。
注意,相位首先在一个方向上,然后在3.5 GHz左右改变方向。
在用Excel绘制的图表上应该更容易看到。
我有什么想法可以找到这个SMA女性短片的偏移延迟?
我附上了两个Touchstone文件。
* sma-short-0ps.s2p是用*无端口扩展*测量的SMA短路。
* sma-short-25.854ps是用* 25.854 ps端口扩展测量的SMA短路*有没有人评论我的结果是否令人惊讶,或者可以做些什么(如果有的话)来改善问题。
也许我只是要求太多的非精密连接器。
DaveEdited:drkirkby于2013年4月3日8:12 PM SMith-Chart-SMA-short-25.854ps-port-extension.PNG26.8 KBPhase-SMA-short.PNG43.1 KBsma-short-25.854ps.s2p59。
6 KB

以上来自于谷歌翻译


     以下为原文

  I've got an HP 8720D VNA and Agilent 85033E calibration kit, and want to measure an SMA female device. That device is actually an SMA short and I want to find the distance between the reference plane and the short. But the results I'm getting don't look too good, and I suspect its due to the mis-match between SMA and 3.5 mm, but I may be wrong.   

But I don't know how best to correct this, or at least reduce its effects.  

If I take the *3.5 mm female short standard* from the 85033E calibration kit, and apply a port extension equal to the offset delay of the short, then on the Smith Chart the device looks like a dot on the left. No great surprise that  

If I now replace the 3.5 mm short with an *SMA female short*, I am unable to find any port extension at which the Smith Chart shows a dot on the left. The Smith Chart view (hand edited as my software was not displaying it very clearly), shows the view with a port extension of 25.854 ps. Note the phase first goes in one direction then changes direction around 3.5 GHz. It should be easier to see on the graphs plotted with Excel.

Any thoughts on what I can do to find the offset delay of this SMA female short?  

I've attached two Touchstone files.  

* sma-short-0ps.s2p is the SMA short measured with *no port extensions*.  
* sma-short-25.854ps is the SMA short measured with *25.854 ps port extensions*

Has anyone any comments as to whether my results are surprising, or what (if anything) can be done to improve matters.  

Perhaps I am just asking too much of a non-precision connector.  

Dave

Edited by: drkirkby on Apr 3, 2013 8:12 PM   
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李青

2019-7-9 08:39:38
> {quote:title = MADENGR写道:} {quote}>看起来我会遇到同样的问题。
请参阅校准子论坛中关于创建SMA校准套件的帖子。
我想你可以尝试(电路)模拟响应以查看不连续性是否在参考平面上,例如Z0中的微小步长,或短路时的电感(延迟之后)。
我的部分问题是短期不是很好。
我后来尝试了更好的短片,事情并没有那么古怪,但我还没有进一步说服。
我喜欢你的另一个水银线的想法,零长度短!
当然,mercuy确实会解散黄金,所以短期可能随着时间的推移越来越短!
当我还是一个在学校的孩子时,我班上的一个名叫保罗的人有一个父亲,他是一个废金属经销商。
保罗说家里有一个甜蜜的罐子,里面装满水银太重了,无法举起。
很多时候,保罗会把这种情况带到学校,我们会玩它,把它拿在手中,倾倒它并将其放入许多小体积中,然后将其组合起来使其变大。
没有人告诉我们这些东西是有毒的。
因此,如果我的任何帖子表明我像帽匠一样疯狂,你知道为什么!
>我可以在我的3D EM软件中做一个粗略的模型。
我已经考虑过使用EM模拟器了,尽管我对N比SMA更感兴趣。
我希望你能看到我开始使用HFSS为HFSS中的HFSS连接器用作校准标准的线程
Ken Wong对此有一些有用的评论。
目前我正忙着在房子里做很多事情,而我的两个VNA(8753A和8720D)都在餐厅里,这让我的妻子烦恼不已!
戴夫

以上来自于谷歌翻译


     以下为原文

  > {quote:title=MADENGR wrote:}{quote}
> Looks like I'll have the same issues.  See my post in the calibration sub-forum about creating an SMA cal kit.  I suppose you could attempt to (circuit) model the response to see if the discontinuity is at the reference plane, such as a slight step in Z0, or inductance at the short (after the delay). 

Part of my problem was the short was not very good. I later tried a better short, and things were not so bizzare, but I have not persued this any further. 

I like your idea on the other thread of mercury for a zero length short! Of course mercuy does disolve gold, so perhaps the short gets shorter and shorter over time! 

When I was a kid at school, someone in my class called Paul had a dad who was a scrap metal dealer. Paul said there was a sweet jar at home so full of mercury that was too heavy to lift. Quite often Paul would bring the mercuty into school and we would play with it, holding it in our hands, pouring it and getting it into lots of small volumes, then combining it to make it bigger.  Nobody told us the stuff is toxic. So if any of my posts would indicate I am as mad as a hatter, you know why! 

> I could probably do a rough model in my 3D EM software.

I've given some thought to using an EM simulator too, though I was more interested in N than SMA. I expect you would have seen the thread I started about using HFSS for this
Model a connector in HFSS to use as a calibration standard
 

There are some useful comments from Ken Wong on that. 

At the moment I am busy trying to do quite a bit in the house, and my two VNAs (8753A and 8720D) are in the dining room, much to the annoyance of my wife! 

Dave
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李青

2019-7-9 08:53:31
> {quote:title = MADENGR写道:} {quote}>哈哈,我们和水星有类似的经历。
我小时候还有1磅的瓶子,记得在学校课桌上的铅笔槽里滚动。
水星肯定是有趣的东西。
作为一个孩子,我不知道它有什么风险。
我知道那些在工作中使用它的人(帽子制造商)确实遭受了长期影响 - 因此这个术语“像帽子一样疯狂”,但也许偶尔的混乱不会把我们所有人带到早期的坟墓。
我的老化学老师曾经是一名工业化学家。
他显然有汞中毒。
显然,他们过去常常用指甲切割来看到它们中的汞。
我不记得他说他对他的影响是什么。
>我把你的S2P文件修复成一个S1P文件。
由于您使用的是#MHz S DB R 50接头,因此您应该使用-99作为虚拟幅度而不是0,否则电路仿真器将会发生故障。
谢谢。
我编写了程序来自己生成.s2p。
它是一个在Sun工作站上运行的C代码。
我会在某个时候修改代码并在未使用的数量上坚持-99。
>然后,我从另一个线程中提到的Wong博士的论文中应用了SMA-3.5mm参考平面不连续模型(分流器C)。
我会读一读那篇论文。
>在接近6 GHz之前,不连续模型没有太大差异(1度)。
我能够通过在参考平面上去除0.3 pH值来将相位响应拉到+/- 1度,这将表明中心引脚缩回,但是0.3 nH似乎太过分了本文中列出的挫折是10
mils(0.254 mm),使用我的经验法则为0.18 nH的键合线,但同样,它是同轴电缆所以不应该那么多。
将电感移动到延迟的另一侧,将其从短标准中去嵌入,并没有给出好的结果。
我使用的短片很差。
我有一些短裤,其中一些有女性的4个插槽,部分,而我展示的结果只有两个插槽。
我以前从未见过任何糟糕的事情。
我写这篇文章的时候我不知道这个。
有了更好的空头,结果不那么古怪,不是先旋转一次,然后另一个围绕史密斯圆图。
戴夫

以上来自于谷歌翻译


     以下为原文

  > {quote:title=MADENGR wrote:}{quote}
> Ha ha, we had similar experiences with Mercury.  I still have the 1 pound bottle I had when I was kid, and remember rolling it in the pencil troughs on the school desks.

Mercury sure is funny stuff. I don't know the risks with messing around with it as a kid. I know people who use it in their job (hat makers), did suffer the long-term effects - hence the term as "mad as a hatter", but perhaps the occasional messing around wont send us all to an early grave. 

My old chemistry teacher used to be an industrial chemist. He apparently got mercury poisoning. Apparently they used to take finger nail cuttings to see the mercury in them. I can't recall him saying what the effects on him was. 

> I took your S2P file and repaired it into an S1P file.  Since you are using # MHz S DB R 50 header you should use -99 for the dummy magnitudes instead of 0, otherwise the circuit simulators will freak out. 

Thank you. I wrote the program to generate the .s2p myself. It is a bit of C code which runs on a Sun workstation. I'll modify the code at some point and stick -99 in the unused magnitudes.

>  I then applied the SMA-3.5mm reference plane discontinuity model (shunt C) from the paper Dr. Wong mentioned in the other thread.

I'll take a read of that paper. 

> The discontinuity model does not make much difference (1 degree) until you approach 6 GHz.  I was able to pull the phase response into +/-1 degree by de-embedding 0.3 pH at the reference plane, which would indicate center pin set-back, but 0.3 nH seems like way too much  The setback listed in the paper is 10 mils (0.254 mm), which is 0.18 nH using my rule of thumb for a bond wire, but again, it's in coax so it should not be that much.  Moving the inductance to the other side of the delay, to de-embed it from the short standard, does not give as nice results.

The short I used was quite poor. I had a number of shorts, some of which have 4 slots in the female, part, and the one I showed the results for has just two slots. I've never seen anything as bad before. I did not know this at the time I wrote that post. With a better short, the results were less bizzare, not rotating first once way, then the other around the Smith Chart. 

Dave
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