how to meas Zo of FT caps?

I have a bunch of small feedthru caps that I need to measure their Zo
to assure it's 50 +/-10 ohms. Any thoughts on how to do it? I'm going
to try to put a 50 ohm load on them and look at them with a network
analyzer. I should be able to get it's Zo from the VSWR, no? Any other
ways?

 

[mike]

sdeyoreo@hotmail.com wrote:

I have a bunch of small feedthru caps that I need to measure their Zo
to assure it's 50 +/-10 ohms. Any thoughts on how to do it? I'm going
to try to put a 50 ohm load on them and look at them with a network
analyzer. I should be able to get it's Zo from the VSWR, no? Any other
ways?

HuH?
Zo is normally associated with the impedance of a transmission line.
A cap looks like...well...a cap. If you can operate a network
analyzer, you obviously understand the difference. Maybe restate the
question so _I_ can understand.
mike

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[Graham W]

sdeyoreo@hotmail.com wrote:

I have a bunch of small feedthru caps that I need to measure their Zo
to assure it's 50 +/-10 ohms. Any thoughts on how to do it? I'm going
to try to put a 50 ohm load on them and look at them with a network
analyzer. I should be able to get it's Zo from the VSWR, no? Any other
ways?

Unless i'm missing something here, these are either:

a.) feedthrough caps and will not have a single value of of Z since caps'
Xc is frequency dependent

or they are

b.) Z-ohm feedthroughs and should be marked as such.

I would opt for the former and query why the question of Zo is being
raised.

Simple low-capacitance feedthroughs are available but their length is so
short that they won't have a Zo worth worth worrying about at frequencies
which don't travel in waveguides!

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