RF Electronics Symbols, Stencils for Office, Visio by RF Cafe
Berkeley Nucleonics Academy RF Boot Camp - RF Cafe
 

About RF Cafe

Kirt Blattenberger - RF Cafe Webmaster

Copyright: 1996 - 2024
Webmaster:
    Kirt Blattenberger,

    BSEE - KB3UON

RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while tying up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived...

All trademarks, copyrights, patents, and other rights of ownership to images and text used on the RF Cafe website are hereby acknowledged.

My Hobby Website:

AirplanesAndRockets.com

Electronics World articles Popular Electronics articles QST articles Radio & TV News articles Radio-Craft articles Radio-Electronics articles Short Wave Craft articles Wireless World articles Google Search of RF Cafe website Sitemap Electronics Equations Mathematics Equations Equations physics Manufacturers & distributors Engineer Jobs LinkedIn Crosswords Engineering Humor Kirt's Cogitations RF Engineering Quizzes Notable Quotes App Notes Calculators Education Engineering magazine articles Engineering software Engineering smorgasbord RF Cafe Archives RF Cascade Workbook 2018 RF Symbols for Visio - Word Advertising RF Cafe Homepage Thank you for visiting RF Cafe!
Anatech Electronics

S-parameter for a FET - RF Cafe Forums

RF Cafe Forums closed its virtual doors in 2012 mainly due to other social media platforms dominating public commenting venues. RF Cafe Forums began sometime around August of 2003 and was quite well-attended for many years. By 2010, Facebook and Twitter were overwhelmingly dominating online personal interaction, and RF Cafe Forums activity dropped off precipitously. If the folks at phpBB would release a version with integrated sign-in from the major social media platforms, I would resurrect the RF Cafe Forums, but until then it is probably not worth the effort. Regardless, there are still lots of great posts in the archive that ware worth looking at.

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

-- Amateur Radio
-- Anecdotes, Gripes & Humor
-- Antennas
-- CAE, CAD, & Software
-- Circuits & Components
-- Employment & Interviews
-- Miscellany
-- Swap Shop
-- Systems
-- Test & Measurement
-- Webmaster

Guest
Post subject: S-parameter for a FET Posted: Wed Aug 10, 2005 2:37 pm
I've a quick question; let's say i'm looking at a smith chart, how would i know if it's a standard FET's response. How does a standard FET look like on smith chart? How about MESFET above 5 GHz? Thanks


Top

Jeanalmira
Post subject: Posted: Tue Aug 30, 2005 1:42 am

General


Joined: Tue Mar 15, 2005 11:43 pm
Posts: 65
Location: Singapore
Hi :

I'm not too sure what do you mean by standard FET?

The S-parameters of device on smith chart depends on its impedance.
e.g. S11 relates to input impedance, while S22 relates to output impedance.

Different type FET has different S-parameters, even same FET has different S-parameters under different bias points.

But generally, the S-parameters for both input and output will be inside smith chart; |S11| <1 and |S22|<1, that will give you most of the cases, potentially unstable conditions, although, maybe there could be unconditionally stable also....

I hope it helps.

Regards,
Jean


Top

Guest
Post subject: Posted: Tue Aug 30, 2005 2:04 pm
I think you might want to take a look at the small signal model of a fet from a electronic circuit book.

Basically you see the series inductances, and series and parallel capacitance parasitics in front of the gate source resistance, and on the drain the dynamic resistance of the fet.

The electrical length to the reference plane might shift all this a bit also.



Posted  11/12/2012
TotalTemp Technologies (Thermal Platforms) - RF Cafe
PCB Directory (Assembly)
Amplifier Solutions Corporation (ASC) - RF Cafe
 

Please Support RF Cafe by purchasing my  ridiculously low−priced products, all of which I created.

These Are Available for Free