Electronics World Cover,TOC,and list of posted Popular Electronics articles QST Radio & TV News Radio-Craft Radio-Electronics Short Wave Craft Wireless World About RF Cafe RF Cafe Homepage RF Cafe in Morse Code Google Search of RF Cafe website Sitemap Electronics Equations Mathematics Equations Equations physics Manufacturers & distributors Engineer Jobs Twitter LinkedIn Crosswords Engineering Humor Kirt's Cogitations Engineering Event Calendar RF Engineering Quizzes AN/MPN-14 Radar 5CCG Notable Quotes App Notes Calculators Education Magazines Software,T-Shirts,Coffee Mugs Articles - submitted by RF Cafe visitors Simulators Technical Writings RF Cafe Archives Test Notes Wireless System Designer RF Stencils for Visio Shapes for Word Search RF Cafe Sitemap Advertising Facebook RF Cafe Forums Thank you for visiting RF Cafe!

Open Shunt Stub Phase - RF Cafe Forums

The original RF Cafe Forums were shut down in late 2012 due to maintenance issues. Original posts:

Amateur Radio | Antennas | Circuits & Components | Systems | Test & Measurement


guest
Post subject: open shunt stub phase Posted: Thu Jan 12, 2006 4:26 am
Hi i asked earlier about quarter-wave form Tlines and you guys helped out a lot. i've another question to ask: i used ideal transmission line models and it told me that I need 23 deg. electrical length for a line series tranmission line and i plotted the mag. and phase of s21 and saw yes the phase is 23 deg (in fact it was -23 deg, why is that?).

however, my main question is this: the model also told me that i need 47 deg. of electrical length for an open shunt stub for something. i then plotted its mag. and phase of s21 but saw that the phase was only 24 deg at the given frequency? why is that? i don't know the concept clearly to know why the phase was 24 deg.--something to do with open stub??. there is nothing special i am doing here. i just took completely ideal models in a CAD program and put two 50 ohms terminations and simulated them. your answer will be much appreciated. how wold be shunt short-circuited stub different? thanks


Top

guest
Post subject: Posted: Thu Jan 12, 2006 7:08 am
one more question: one can have open circuit single shunt stub but it said that when doing layout it is a good idea to have balanced shunt stubs, meaning half the length on either side of a series line, like a + sign. i calculated exactly how to convert one shunt stub to balanced stub...my question is when one simulates this should you get exactly the same response, what i am getting is that the phase are same but the magnitude are opposite. in the single shunt open stub i have phase starting from 1 (or 0 dB) and decreasing a bit throughout he frequency sweep but for balanced shunt open stub it start from 0 magnitude and approaches like .6 through its frequency sweep!! doesn't make sense. please provide explanation. my layout is i think ok, its like a + with both sides open and then placed ports on the sides where the signal enters and exits


Top

Rod
Post subject: Posted: Thu Jan 12, 2006 2:09 pm
the phase are same but the magnitude are opposite

Is that what you meant to say? I am almost ready to answer all of your questions and more! After 3 more cups of coffee.


Top

guest
Post subject: Posted: Fri Jan 13, 2006 5:35 am
yeah....that's what i meant but i think i figure out the problem but would still like to know your feedback and the answer to the first one. thanks


Top

Honza
Post subject: 23 or 24Posted: Wed Jan 18, 2006 2:47 am

Captain

Joined: Tue Dec 13, 2005 2:42 am
Posts: 5
Location: Czech Rep.
I think that this misunderstanding comes from the model/software you used.
1) Why -23 and not +23deg? ..I guess that the SW calculates the phase as decreasing quantity with increasing distance from the port on which the fictive signal generator is applied.
2) Why 24 deg and not 23 deg? (I HOPE I understood your question well - that after adding a shunt line the phase of s21 changed from 23 to 24 deg.) It is sure that some added line MUST change phase relationships in the system - if the added line has some significant length in comparison with the rest of the network. ...You can see this fact if you use Smith chart. Try to put some serial line with parallel line and see what will happen with the phase

Honza.




Posted  11/12/2012

RF Cafe Software

   Wireless System Designer - RF Cafe
Wireless System Designer

RF & EE Symbols Word
RF Stencils for Visio
Calculator Workbook
RF Workbench
Smith Chartâ„¢ for Visio
Smith Chartâ„¢ for Excel

About RF Cafe

Kirt Blattenberger - RF Cafe WebmasterCopyright
1996 - 2022
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 Internet was still largely an unknown entity at the time and not much was available in the form of WYSIWYG ...

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

Try Using SEARCH
to Find What You Need. 
There are 1,000s of Pages Indexed on RF Cafe !

height-line