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!
Boonton RF Power Measurement

What capacitor to use to filter out 10GHz signal - 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


Post subject: What capacitor to use to filter out 10GHz signal Posted: Mon Dec 11, 2006 3:20 pm


Joined: Mon Dec 11, 2006 3:17 pm

Posts: 2

I have a 10GHz signal riding on all my DC inputs. I am thinking of using a low pass RC filter. But what kind of capacitor to use? Ceramic MLCC?



Post subject: 10 GHz bypassPosted: Wed Dec 13, 2006 12:44 am


Joined: Wed Feb 22, 2006 3:51 pm

Posts: 104


You say that you have "have a 10GHz signal riding on all my DC inputs".

A classic approach is to bypass the DC inputs, and use a resistor, inductor, or lossy ferrite to isolate the DC from the RF.

However, I'd like to caution you that one possible problem with an RC lowpass is the quality of the ground. At 10 GHz (wavelength about 3 cm), it doesn't take much distance to be an appreciable fraction of a wavelength. So, while a small MLC SMT capacitor would probably work, proper functioning would really almost more depend on the available ground path. As a rule of thumb, you should reach a ground plane within 1/10 of a wavelength, or 3mm. (And preferably less!)

Physical layout is increasingly critical as the frequency goes up.

Good Luck!




Post subject: Posted: Thu Jan 18, 2007 2:57 pm


Joined: Thu Jan 11, 2007 12:59 pm

Posts: 4

Just wanted to mention that 10GHz easily can get outside an ordinary T-filter often used in digital circuits, as mentioned earlier the dimensions of the filters are often larger than 3mm. In a project some years ago I found feedthrough capacitors specified to 10GHz, think it was Murata but there are probably plenty of them out there - just be sure that they really are specified at least to the frequency you use or have problems with!





Post subject: Posted: Thu Jan 18, 2007 5:52 pm


Joined: Thu Sep 25, 2003 1:19 am

Posts: 50

Location: texarcana

Check out Vishay. They have some pretty ok mos caps. I use them up to 10GHz.

Posted  11/12/2012

Windfreak Technologies SynthHD PRO - RF Cafe
Amplifier Solutions Corporation (ASC) - RF Cafe
withwave microwave devices - RF Cafe
Exodus Advanced Communications Best in Class RF Amplifier SSPAs
everythingRF RF & Microwave Parts Database - 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


    Kirt Blattenberger,


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: