Thank you for visiting RF Cafe! 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 RF Cafe Homepage Thank you for visiting RF Cafe!

Noise Figure Increase - 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


shireesha
 Post subject: Noise figure increase
Posted: Wed Dec 09, 2009 6:40 am 
 
Captain

Joined: Wed Jun 04, 2008 3:23 am
Posts: 11
Hello,
I am trying to design a 30 dB Low noise amplifier at 9.5 GHz using the FHX13X super low noise HEMT from fujitsu as the first stage. I am able to meet all the specs but I have encountered a weird phenomenon. During the noise figure measurement for a certain percentage of modules the noise figure starts low (around the designed spec of 1.2 dB) and goes on to slowly increase with time to 2.5 dB. For every measurement cycle (of the noise figure analayzer) it seems to increase 0.02 dB. What are the possible reasons for this?

Thanks.


 
   
 
maxwell
 Post subject: Re: Noise figure increase
Posted: Fri Dec 18, 2009 12:13 pm 
 
Captain
 

Joined: Mon Sep 01, 2003 6:59 pm
Posts: 13
Location: Boston
Are these packaged LNA, or open substrate? The increasing NF over time suggests either a charge accumulating (possibly bias capacitance), or a temperature realted issue. Both could be caused by poor solder joints. Have you already ruled out these two possibilities?






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