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Question on test scheme design for 4-port microstrip circuit - RF Cafe Forums

Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would be best to just archive the pages to make all the good information posted in the past available for review. It is unfortunate that the scumbags of the world ruin an otherwise useful venue for people wanting to exchanged useful ideas and views. It seems that the more formal social media like Facebook pretty much dominate this kind of venue anymore anyway, so if you would like to post something on RF Cafe's Facebook page, please do.

Below are all of the forum threads, including all the responses to the original posts.


 Post subject: Question on test scheme design for 4-port microstrip circuit
Posted: Thu Sep 24, 2009 2:39 pm 
 
Lieutenant

Joined: Wed Jul 09, 2008 11:51 am
Posts: 4
Location: Chicago
Dear all,

I designed a small four-port microstrip circuit (device under test), and obtained the simulation results. Since this 4-port microstrip circuit is very small, it does not have enough space for SMA connector mounting. Now I want (but I have no idea) to design a proper test scheme for purpose of the SMA-connector measurement of S parameters of this tiny four-port DUT by using four-port vector network analyzer. I really appreciate whatever help you could offer me on the test scheme design.

Thanks a lot.

Sincerely yours,
Kevin

Image

_________________
Pursuing perfectness pushes us to progress


 
   
 
 Post subject: Re: Question on test scheme design for 4-port microstrip circuit
Posted: Thu Sep 24, 2009 3:46 pm 
 
Captain
User avatar

Joined: Thu Oct 12, 2006 7:50 am
Posts: 6
Hi Sageme,

If you only have a couple DUTs to measure, then you can probably solder a short section of small semi-rigid coax to the board that has an SMA on the other end. I've had great success with that up into the 6 GHz region (could probably go higher, butI've never needed to).

For measuring a large number of DUTs, a fixture will be necessary. I've never used one myself, but I see that a company called Gigalane has a productio quality fixture for measuring your type of PCB.



http://www.gigalane.com/index.html?mode=02_01_01_01&pduid=93

_________________
Thanks,
Jess


 
   
 
 Post subject: Re: Question on test scheme design for 4-port microstrip circuit
Posted: Mon Sep 28, 2009 12:13 pm 
 
Lieutenant

Joined: Wed Jul 09, 2008 11:51 am
Posts: 4
Location: Chicago
Dear Jessica,

Thanks a lot for the information your provided.

Actually, I only have a couple of DUTs to measure. I think it may be very difficult to solder a short section of small semi-rigid coax to the board for measurement, since our DUTs are so miniature that it may not have enough space for soldering. The distance between two adjacent ports is about 36mil=0.9mm on the same side (as indicated in the picture above), and the distance between adjacent port is about 164mil=4.2mm on two adjacent sides, which is the same as the DUT's length.

For the test fixture in your reply, it might be not proper for our measurement for the same reason that our DUT is too miniature. I checked the specifications of this test fixture. It requires that minimum length of DUT is 9mm and minimum width of DUT is 2.5mm.

What do you think of this? Or could you please offer some suggestions? Thank you so much!

Sincerely,
Kevin


Jessica wrote:
Hi Sageme,

If you only have a couple DUTs to measure, then you can probably solder a short section of small semi-rigid coax to the board that has an SMA on the other end. I've had great success with that up into the 6 GHz region (could probably go higher, butI've never needed to).

For measuring a large number of DUTs, a fixture will be necessary. I've never used one myself, but I see that a company called Gigalane has a productio quality fixture for measuring your type of PCB.



http://www.gigalane.com/index.html?mode=02_01_01_01&pduid=93

_________________
Pursuing perfectness pushes us to progress




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