AnsweredAssumed Answered

Can 8753C do conjugate match?

Question asked by beatouyoo on Sep 17, 2010
Latest reply on Oct 28, 2010 by beatouyoo

Like • Show 0 Likes0
Comment • 5

I want to do impedance match of my device to the network analyzer.
I can't explain my data right now. It seems the peaks only happen to be impedance matched with the 8753C.
I know that the 8751A can do conjugate match but didn't found this function in my 8753C.
Does any one know how to do it with the 8753C?
Thanks in advance.

No one else has this question

Outcomes

5 Replies

scottrf Sep 17, 2010 12:51 PM
Mark Correct
Correct Answer
Your question is confusing. The analyer's ports are 50 ohms, so your first question implies that you want to match your device to 50 ohms, but I'm not sure that's what you want to do.

The 8753C will measure the complex impedance of a device. From that you can design a circuit to match to a different impedance, quite often 50 ohms.

Scott O
Like • Show 0 Likes0
Actions
beatouyoo Oct 7, 2010 3:24 PM
Mark Correct
Correct Answer
Yes. That's what I want to do.

I was asking previously that whether 8753C has the function of conjugate match as the 8751A has, so that I don't need to build up a circuit and connect it between the DUT and the network analyzer. It seems 8753C does not have this built-in function.

Usually, how to insert a circuit between the DUT and the network analyzer? I tried it like this: Network analyzer <----> apc-7 <----> cable <----> BNC <---> MATCHING CIRCUIT <-----> BNC <----> cable <----> SMA <-----> GSG probe <---> DUT. But it is really bad because of noise. Any ideas how to improve this? Thanks.

"
Your question is confusing. The analyer's ports are 50 ohms, so your first question implies that you want to match your device to 50 ohms, but I'm not sure that's what you want to do.

The 8753C will measure the complex impedance of a device. From that you can design a circuit to match to a different impedance, quite often 50 ohms.

Scott O
"
Like • Show 0 Likes0
Actions
Dr_joel Oct 8, 2010 10:49 AM
Mark Correct
Correct Answer
Nope. 8753 doesn't have this function. ENA and PNA (more modern VNA products) both do.
Like • Show 0 Likes0
Actions
scottrf Oct 8, 2010 11:32 AM
Mark Correct
Correct Answer
Network analyzer <----> apc-7 to SMA adaptor <-----> GSG probe <---> DUT

calibrate at probe tip. If you have no means to do that, then set start and stop frequencies for as narrow a range as you can and adjust Electrical Delay (<SCALE REF><ELECTRICAL DELAY>) until the sweep on a Smith Chart display looks like a dot at the right side of the chart with no DUT on the probe. You won't be able to do this perfectly without calibrating, but get the sweep to look like a small loop on the real axis.

measure S11 of DUT. design matching circuit from results. fabricate board with match directly connected to DUT.

Network analyzer <----> apc-7 to SMA adaptor <-----> GSG probe <---> DUT with matching circuit

If results are off, tweek matching circuit.

You can't have anything, cables, connetors, etc., between the match and the DUT. The match will transform the DUT's impedance to 50 ohms, and after that you can have connectors, cables, adaptors, etc., as long as they are all 50 ohms.
Like • Show 0 Likes0
Actions
beatouyoo Oct 28, 2010 1:40 PM
Mark Correct
Correct Answer
Thanks a lot, Scott. You mean even if making the device and the matching network on PCB will not work, when they are separated by cables, connectors, etc?

"
Network analyzer <----> apc-7 to SMA adaptor <-----> GSG probe <---> DUT

calibrate at probe tip. If you have no means to do that, then set start and stop frequencies for as narrow a range as you can and adjust Electrical Delay (<SCALE REF><ELECTRICAL DELAY>) until the sweep on a Smith Chart display looks like a dot at the right side of the chart with no DUT on the probe. You won't be able to do this perfectly without calibrating, but get the sweep to look like a small loop on the real axis.

measure S11 of DUT. design matching circuit from results. fabricate board with match directly connected to DUT.

Network analyzer <----> apc-7 to SMA adaptor <-----> GSG probe <---> DUT with matching circuit

If results are off, tweek matching circuit.

You can't have anything, cables, connetors, etc., between the match and the DUT. The match will transform the DUT's impedance to 50 ohms, and after that you can have connectors, cables, adaptors, etc., as long as they are all 50 ohms.
"
Like • Show 0 Likes0
Actions

Can 8753C do conjugate match?

Outcomes

Related Content

Recommended Content