How to measure impedance of customize connector

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noisepic

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I've design an adapter which convert from N-type female to "X" type.
N type is 50 Ohm
X type desired 75 ohm.

But how to measure the impedance of X-type?

Thanks,
 

The performance of a connector will be measured by determining reflection factor or VSWR with connected cable. But I don't fully understand the question. Adapting 50 to 75 ohm involves some impedance matching element, what are you trying to achieve?
 

noisepic said:
I've design an adapter which convert from N-type female to "X" type.
N type is 50 Ohm
X type desired 75 ohm.

But how to measure the impedance of X-type?

Thanks,
Click to expand...

Just calibrate a Network Analyzer with N-Type SOL Cal kit, then connect your adapter and
terminate it with a 75 Ohm Load on the X Conn. Then Measure the S11. This will give you an
accumulated match. If it shows bad performance you will have to determine if there is a Bad "N"
design, a bad "X" Design or a bad "75 Ohm" Load. But if you get a VSWR of better than >-40dB
you can assume it's a decent design, and could safely used for most tests with exceptions to very
hard, sensitive tests.

Note the Minimum Loss for a 50-75 Ohm conversion is 5.75dB, so your design should have that much loss.
 


That's great. you've my point. X-type is my own design.
But I can not find 75 Ohm load to connect to X Connector.
Is there any way to buy/manufacture 75 terminator for customized connector?

Thanks
 

noisepic said:
That's great. you've my point. X-type is my own design.
But I can not find 75 Ohm load to connect to X Connector.
Is there any way to buy/manufacture 75 terminator for customized connector?

Thanks
Click to expand...
Just get the mate to your X-Connector and solder 2 small (As Possible) 150 Ohm resistors
to the Center pin and Ground. So you will 150 // 150 = 75.
 

My X-type connector has diameter of 34mm, I suspect the accurancy of your method. Because it doesn't cover the perimeter of the connector.

Pls advise
 

My X-type connector has diameter of 34mm, I suspect the accurancy of your method. Because it doesn't cover the perimeter of the connector.
Click to expand...
Your answer clarifies that the problem is still rather vague. As already mentioned, the term "impedance of connector" is dubious itself. If you say, you have designed a custom 75 ohm connector, I presume you have a specification, e.g. VSWR < value x in a frequency range y to z. If you know to design a coaxial connector, why can't you design a termination for it?

A termination for connector of 34 mm diameter should be ideally imagined as a distributed resistor.

It would be helpful for the discussion, if you mention what kind of 50-to-75 ohm conversion is implemented in your design.
 

50-75 ohm conversion is quarter- wave type which in form of coaxial line, made from copper.
How to design termination? does it similar like this:
**broken link removed**

Which is "X"type connector instead of N-type.

Thanks
 

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