[SI-LIST] Re: Too much predicted loss
- From: Scott McMorrow <scott@xxxxxxxxxxxxx>
- To: "You, Yang" <yang.you@xxxxxx>, silist <si-list@xxxxxxxxxxxxx>
- Date: Wed, 13 Jul 2005 10:13:13 -0400
Yang,
I'm glad to hear you're working with Ansoft. Since SIWave is a bit of a
hybrid fullwave simulator, you might want to look at possible issues
like excitation of planar resonance modes that can color the extracted
s-parameters. It is possible that the loss you are seeing is an
artifact of the setup of the planes. If you are not modeling your
measurement points in the same way that you are making the measurements,
or you are not stitching the planes identically to the design, lots of
interesting things can come up, as it is possible to excite modes in
simulation that may not be excited in your system.
scott
Scott McMorrow
Teraspeed Consulting Group LLC
121 North River Drive
Narragansett, RI 02882
(401) 284-1827 Business
(401) 284-1840 Fax
http://www.teraspeed.com
Teraspeed® is the registered service mark of
Teraspeed Consulting Group LLC
You, Yang wrote:
>Scott,
> I am working with an Ansoft engineer right now. I was just
>seeing if anyone had a similar experience. Thanks for your reply.
>
>Yang You
>
>-----Original Message-----
>From: Scott McMorrow [mailto:scott@xxxxxxxxxxxxx]
>Sent: Wednesday, July 13, 2005 8:54 AM
>To: You, Yang
>Cc: si-list@xxxxxxxxxxxxx
>Subject: Re: [SI-LIST] Too much predicted loss
>
>Yang,
>
>This is an issue that should be discussed directly with your Ansoft
>applications engineer. The problem may be setup, your measurements or a
>problem with the simulator. In all of these cases, Ansoft can provide
>valuable expertise.
>
>regards,
>
>scott
>
>Scott McMorrow
>Teraspeed Consulting Group LLC
>121 North River Drive
>Narragansett, RI 02882
>(401) 284-1827 Business
>(401) 284-1840 Fax
>
>http://www.teraspeed.com
>
>Teraspeed(r) is the registered service mark of
>Teraspeed Consulting Group LLC
>
>
>
>You, Yang wrote:
>
>
>
>>Hi,
>> I'm working with the SIWave software on a board with some
>>test traces but the results of the simulation indicate about 8 db more
>>loss than is actually seen in the lab on the actual board. I imported
>>the board directly from the layout tool and setup the stackup but I
>>think the dielectric layers I specified might be a little thinner than
>>on the actual board. Would that cause more loss to show up in the
>>s-parameters? What other factors might be contributing to this? Thanks
>>for your help.
>>
>>
>>
>>Yang You
>>
>>
>>
>>Texas Instruments, Inc.
>>
>>
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