[SI-LIST] Question for CST Microwave Studio experts

Hi,
 
We are evaluating CST MWS recently and I'm having some issues with the
waveguide port solutions. Set up a simple differential through via
(microstrip on top layer of PCB to microstrip on bottom, no stubs) and try
to study the impact of antipad clearance on the differential return loss and
insertion loss. Using waveguide port and multipin definition, I got the
differential insertion loss and return loss. The insertion loss curve looks
rather wield, as I have -0.7dB loss from DC to about 4GHz, but then it
climbs up to -0.4 dB from 4 to 10 GHz. I can't explain why I have higher
insertion loss at low frequency. Single-ended S parameter computed from the
mixed model results show the same trend.
 
Using the exact same model but replace waveguide ports with discrete port
and re-run the same simulation. The resulted single-ended insertion loss
makes sense where I have a nice slope with very small insertion loss at low
frequency and increase linearly as frequency goes higher.
 
I had a few email exchange with CST tech support but I have not received a
good explanation. I was wondering if any users here on the list have similar
problem ?
 
Thanks
 
Perry
 
======================================= 

Perry Qu 

Design & Qualification, Alcatel Canada 

600 March Road, Ottawa ON, K2K 2E6 

DID: 613-7846720  Fax: 613-5993642 

Email: perry.qu@xxxxxxxxxxx 

======================================= 

 


------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field

or to administer your membership from a web page, go to:
http://www.freelists.org/webpage/si-list

For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field

List FAQ wiki page is located at:
                http://si-list.org/wiki/wiki.pl?Si-List_FAQ

List technical documents are available at:
                http://www.si-list.org

List archives are viewable at:     
                http://www.freelists.org/archives/si-list
or at our remote archives:
                http://groups.yahoo.com/group/si-list/messages
Old (prior to June 6, 2001) list archives are viewable at:
                http://www.qsl.net/wb6tpu

Other related posts: