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 Calculators Education Engineering Magazine Articles Engineering software RF Cafe Archives RF Cascade Workbook 2018 RF Symbols for Visio - Word Advertising RF Cafe Forums Magazine Sponsor RF Cafe RF Electronics Symbols for Visio RF Electronics Symbols for Office Word RF Electronics Stencils for Visio Sponsor Links Saturday Evening Post NEETS EW Radar Handbook Microwave Museum About RF Cafe Aegis Power Systems Anritsu Alliance Test Equipment Amplifier Solutions Anatech Electronics Axiom Test Equipment Berkeley Nucleonics Bittele Centric RF Conduct RF Copper Mountain Technologies Empower RF everything RF Exodus Advanced Communications Innovative Power Products ISOTEC KR Filters Lotus Systems PCB Directory Rigol RF Superstore San Francisco Circuits Reactel RFCT TotalTemp Technologies Triad RF Systems Windfreak Technologies Withwave LadyBug Technologies Wireless Telecom Group Sponsorship Rates RF Cafe Software Resources Vintage Magazines Thank you for visiting RF Cafe!
Axiom Test Equipment - RF Cafe

Input impedance - RF Cafe Forums

RF Cafe Forums closed its virtual doors in 2010 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. 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.

NOTICE: The original RF Cafe Forum is available again for reading, and the new RF Cafe Blog is an active board.

-- Amateur Radio

-- Anecdotes, Gripes, & Humor

-- Antennas

-- CAE, CAD, & Software

-- Circuits & Components

-- Employment & Interviews

-- Miscellany

-- Swap Shop

-- Systems

-- Test & Measurement

-- Webmaster

Measures
 Post subject: Input impedance
Posted: Mon Mar 01, 2010 11:35 am 
 
Captain

Joined: Tue Dec 15, 2009 10:22 am

Posts: 10

How can I obtain the input impedance of my circuit from the measured S-parameters?

Is the expression Zin=Zo*(1+S11)/(1-S11) a general expression, or it is only valid in the cases in which GammaL is zero? I don't obtain the input impedance using this expression.

Is GammaL zero occurs only when the load impedance is equal to the impedance of the network? Or does it occur whenever the load impedance is equal to the reference impedance?

Does anybody know which is the expression than ADS uses to obtain the Zin from the S11 parameter? I know this expression works perfectly, but I would like to obtain Zin by myself from the measured S-parameters, not using ADS (I cannot use touchstone files).

Thank you very much


 
   
 
alperuslu
 Post subject: Re: Input impedance
Posted: Fri Mar 05, 2010 7:34 pm 
 
Lieutenant

Joined: Fri Mar 05, 2010 9:02 am

Posts: 2

They are general expressions

 
   
 
PeterMartin
 Post subject: Re: Input impedance
Posted: Wed Apr 14, 2010 2:08 am 
 
Lieutenant

Joined: Sun Apr 04, 2010 7:13 pm

Posts: 2

The spread sheet program "matching network calculator" which is available for free on this page:

http://www.rfshop.co.uk/blog/downloads

can do what you need.

For example, it will convert the reflection coefficient

Mag =0.35 Angle = 78 degs , in a 50 ohm system, into an impedance of :

Z=44.91+j35.04 ohms

Does that sound like the right answer?

Incidentally, the program uses the same equation you mention. Maybe your problem was in the manipulation of complex numbers?

Posted  11/12/2012

Innovative Power Products Couplers
RF Electronics Shapes, Stencils for Office, Visio by RF Cafe
Innovative Power Products Passive RF Products - RF Cafe
Exodus Advanced Communications Best in Class RF Amplifier SSPAs
RF Superstore (RF Components) - RF Cafe

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

These Are Available for Free

 

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