# Insertion Loss? - RF Cafe Forums

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

Qacer
 Post subject: Insertion loss? Posted: Tue Feb 06, 2007 10:18 pm
 Captain

Joined: Sat Apr 23, 2005 2:09 pm
Posts: 19
Location: Tampa, FL
Hi

Is cable loss the same as insertion loss?

If I were to test a cable under a calibrated network analyzer setup, would I be able to figure out the cable loss using the S-params?

I'm thinking that insertion loss is just S12 - S11, but I don't know much anyway.

Thanks!

Jeanalmira
 Post subject: Posted: Wed Feb 07, 2007 3:47 am
 General

Joined: Tue Mar 15, 2005 11:43 pm
Posts: 67
Location: Singapore
Hi :

The insertion loss is basically the loss as the ratio of Pout and Pin. Or, well known as transmission coefficient.
So insertion loss = |S21| and since the cable is passive device, so |S12|=|S21| . If the cable is low-loss, the |S21|=|S12| must be somehow equal or close to zero dB.

In addition, S11 refers to reflection coefficient, which means how much the input power that is reflected. Again as cable is passive device, so |S11| = |S22|. at low-loss cable, the |S11| = |S22| must show low values, preferable <-20dB.

I hope it helps.

Regards,
Jean

Qacer
 Post subject: Posted: Sat Feb 10, 2007 4:54 am
 Captain

Joined: Sat Apr 23, 2005 2:09 pm
Posts: 19
Location: Tampa, FL
Thanks, Jean!

Posted  11/12/2012

RF Cafe Software

Wireless System Designer

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

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 !