Windfreak Technologies Frequency Synthesizers - RF Cafe
LadyBug Technologies LB5944A RF Power Sensor - RF Cafe

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:

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 App Notes Calculators Education Engineering magazine articles Engineering software Engineering smorgasbord RF Cafe Archives RF Cascade Workbook 2018 RF Symbols for Visio - Word Advertising RF Cafe Homepage Thank you for visiting RF Cafe!
Innovative Power Products Couplers

Shielding and grounding - RF Cafe Forums

RF Cafe Forums closed its virtual doors in 2012 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. If the folks at phpBB would release a version with integrated sign-in from the major social media platforms, I would resurrect the RF Cafe Forums, but until then it is probably not worth the effort. 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.

-- Amateur Radio
-- Anecdotes, Gripes & Humor
-- Antennas
-- CAE, CAD, & Software
-- Circuits & Components
-- Employment & Interviews
-- Miscellany
-- Swap Shop
-- Systems
-- Test & Measurement
-- Webmaster

Post subject: Shielding and grounding Posted: Mon Sep 29, 2008 12:20 pm


Joined: Mon Sep 29, 2008 11:50 am
Posts: 1
Being new to RF design from a digital background, my first design at a new company has me a little troubled. The RF engineers want to ground the shield around the RF cavities to the ground referenced by the RF traces (analog ground). The shield is then physically connected to the chassis for thermal dissipation. From a signal quality perspective, this creates a ground loop with the ground tied at multiple points to the chassis.

The thermal dissipation is required, as this unit will generate lots of heat. The RF engineers were not happy when I wanted to isolate chassis ground from analog ground since it would compromise the Faraday cage (the analog and chassis ground would be connected at the output of the power supply -- standard "star" system layout). They seem perfectly happy with the grounding situation, which contradicts common practice.

This cannot be the first time that an issue like this has arisen. How is shielding and grounding typically handled in RF design? How should the design be handled if the shield is also being used as a thermal path to the chassis? Are there electrically isolated (but thermally shorted) shields that can be constructed or COTS? Thanks in advance for relaying your experiences.



Post subject: Posted: Thu Oct 02, 2008 3:24 pm

Site Admin

Joined: Mon Jun 27, 2005 2:02 pm
Posts: 373
Location: Germany
Hello Jay,

You think in digital concept, which is not true for RF.

In RF the ground is VERY important and crucial for the good operation of the circuit.

A good design practice is to ground any plane which does not contain RF signal (As wide as possible) and a complete uniterrupted GND layer underneath the RF signals. The GND planes on the top layer should be connected to the GND layer with as many vias as possible.

The shielded cans which you describe should also be connected to GND planes and GND layer through vias. The cans are a good mean to dissipate the heat. There are also shielded cans with holes on the cover to better dissipate the heat generated inside the can.

If you want to separate digital GND from RF GND, it is a good idea to form 2 different planes for both grounds (Either on the same layer or in different layers) and to connect them near the power supply. If there are high current flowing, you can do the connecton in several locations on the board by using 0-ohm resistors or coils.

Posted  11/12/2012
high frequency PCB of PCBONLINE
RF Electronics Shapes, Stencils for Office, Visio by RF Cafe
LOTUS Communications Systems Modular RF Component Building Blocks - RF Cafe

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

These Are Available for Free