Custom Search
Over 10000 Pages Indexed
Your Host
Click here to read about RF CafeKirt

... single-
what an
engineering website
should be.

View the YouTube RF Cafe Intro Video Carpe Diem!
(Seize the Day!)

5CCG (5th MOB):
My USAF radar shop

Hobby & Fun

Airplanes and Rockets:
My personal hobby website

Equine Kingdom:
My daughter Sally's horse
riding business website -
lots of info

•−•  ••−•    −•−•  •−  ••−•  •
RF Cafe Morse Code >Hear It<

Job Board

About RF Cafe©

RF Cafe E-Mail

Ansoft Designer, Microwave office, or ALPAC - 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: Ansoft Designer, Microwave office, or ALPAC Posted: Wed Oct 19, 2005 4:24 pm
I want to get the s parameter of the transistor.
If I have the spice model of the transistor, am I able to get the S parameter of the transistor using any of these softwares?


Post subject: S-parameters from SPICE modelPosted: Wed Oct 19, 2005 10:35 pm
Actually, all you need is SPICE. Set up the appropriate measurement circuit, simulate, and you've got it.

Good Luck!


Post subject: Posted: Thu Oct 20, 2005 7:10 am


Joined: Thu Oct 06, 2005 6:34 am
Posts: 3
A very good example available in the installation folder of microwave Office....

C:\Program Files\AWR\AWR2004\Examples\Circuit Features\NEW--Models--NEW\New Nonlinear Models.emp




Post subject: Re: S-parameters from SPICE modelPosted: Fri Oct 21, 2005 3:06 pm
Guest wrote:
Actually, all you need is SPICE. Set up the appropriate measurement circuit, simulate, and you've got it.

Good Luck!

But I won't get s-parameters out of pspice,


Post subject: SPICEPosted: Fri Oct 21, 2005 8:27 pm
S-parameters are essentially nothing but reflection coefficients: ratios of voltages and currents. You can get these out of SPICE, you do have to do some work to set up the necessary measurement scaffolding.

Hmm - this may be an area worth writing an article about...

Good Luck!


Post subject: Posted: Sat Oct 22, 2005 12:43 am


Joined: Thu Oct 06, 2005 6:34 am
Posts: 3
Try this in Microwave Office, very simple

1. Build the schematic using spice model & setup input & output biasing options...

2. Simulate the circuit

3. export the s-parameters from output files section...

If you have problems send me the spice model with biasing values..I will send you s-parameters..



Post subject: Posted: Sun Oct 23, 2005 6:48 am


Joined: Fri Sep 02, 2005 7:25 pm
Posts: 34
Location: Hampshire UK
The guest is right in that in principle once you have a SPICE model, you can contrive the s-parameters, provided the SPICE model is good enough. That is, you end up with something that agrees with measured s-parameters. Working from s-parameter end has huge value in designing matching arrangements for best noise or IIP3, at the same time keeping an eye on stability. Then you can get back to the non-linear simulations / bias / and layout effects.

This is OK, but having a "one-click" approach to "export" implies having a tool like Microwave Office. This cannot can be taken for granted. Its a bit of a journey to set up a series of simulated s-parameter measurements using contrived SPICE circuits, and then take the leap of faith that they agree with a measured device.

Do they really? So what of the data .s2p files we get? Are they churned out by a manufacturer who had a SPICE model, and then made a simulator do "export"? I think they measure s-parameters first!
For passive networks it might be OK, but I would be cautious of s-parameters derived in this way for any semiconductor device, coupler, magnetic core device, etc.

Posted  11/12/2012
A Disruptive Web Presence

Custom Search
Over 10,000 pages indexed! (none duped or pirated)

Read About RF Cafe
Webmaster: Kirt Blattenberger

RF Cafe Software

RF Cascade Workbook
RF Cascade Workbook is a very extensive system cascaded component Excel workbook that includes the standard Gain, NF, IP2, IP3, Psat calculations, input & output VSWR, noise BW, min/max tolerance, DC power cauculations, graphing of all RF parameters, and has a graphical block diagram tool. An extensive User's Guide is also included. - Only $35.
RF system analysis including
frequency conversion & filters

RF & EE Symbols Word
RF Stencils for Visio

Product & Service Directory
Personally Selected Manufacturers
RF Cafe T-Shirts & Mugs

RF Cafe Software

Calculator Workbook
RF Workbench
Smith Chart™ for Visio
Smith Chart™ for Excel