[SI-LIST] [SI-LIST]-COUPLER- How do you perform a frequency sweep of a differential coupled line model in Hspice ?
- From: "Geva" <geva@xxxxxxxxxxx>
- To: <jstahl@xxxxxxxxx>, <si-list@xxxxxxxxxxxxx>
- Date: Tue, 17 Feb 2004 20:20:18 -0800
Hi Jon,
If you are using a loose coupling of >20 dB at 50 Ohm design, while using
as example, line width of 4 mil and spacing of 5 mils in-between
them, the coupler loss is insignificant, and I think you don't need to
calculate it at all, as most of the power will go through, and only ~5% will
be coupled out.
Anyway, I don't think the HSpice is the right tool for couplers calculation.
Even for single trace loss calculation it is not the best choice, as it
make a big difference which loss calculation type you are using on this SW.
I think that EPlanner, as a SI SW tool, will give you a more accurate
results, without wasting too much of your time on it.
In case you need to get a very accurate theoretical coupling and loss
results of a coupler, you can use microwave SW such as ADS, NSOFT or
others equivalent.
Ehood Geva
----- Original Message -----
From: "Jon Stahl" <jstahl@xxxxxxxxx>
To: <si-list@xxxxxxxxxxxxx>
Sent: Tuesday, February 17, 2004 6:28 PM
Subject: [SI-LIST] How do you perform a frequency sweep of a differential
coupled line model in Hspice ?
Hi All,
I would really appreciate a suggestion on the proper way to perform a
frequency sweep of a differential coupled line model I have using
Hspice. I would like to determine the insertion loss vs. frequency for
the line when being driven by differential stimulus.
For a single line, it seems trivial to do the following:
Vinput input 0 ac=1
.print ac vdb(output, input)
However, I have had understanding how to perform the equivalent for
a coupled lines. For stimulus I have tried all of the following:
Vin_p in_p 0 ac=0.2
Vin_n 0 in_n ac=0.2
---
Vin_p in_p 0 ac=0.2
Vin_n in_n 0 ac=-0.2
---
Vin_p in_p 0 ac=0.2
Vin_n in_n 0 ac=0.2,180
---
.print ac decibels=PAR('20 * log(v(out_p, out_n)/v(in_p, in_n))')
However, when I do this I always get ZERO for the differential input
voltage v(in_p, in_n) (???), which of course messes up the result.
I have even tried the following:
Vstim in_p in_n 0 ac=1
Which just produces bizarre results.
Any insights into how to do this would be greatly appreciated ...
Thanks,
Jon Stahl
Avici Systems, Inc.
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Other related posts:
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