best metal for shield

[Anjali]

hi
Can neone help me in selecting the best metal that can be used to make a shield to avoid radiation from the board.

Anjali

[randychase]

In the past I have used a stamped copper or brass, nickle plated. This allows the tabs to be soldered. If you are not soldering it down, you can use many materials such as machined out aluminum, stamped steel.

[Anjali]

hi
thanks for ur help...
Can u tell me if a sheild made of stamped copper or brass, nickle plated will be able to absorb radiation in the frequency range of 100-300 MHz?

[MisterE]

It doesn't take a special metal to shield well so long as there is a good connection to ground, and your enclosure is essentially "air tight". Any gaps, seems, or even corrosion at joinning peices will allow RF to escape. The higher the frequency the smaller the required gap...

Back when I used to run preliminary scans for RF emissions I once discovered that a long powder coated face plate was not conducting with the part of the chassis that was ground lugged. The result was the long straight metal edge was acting as an antenna making the device focus it's normally not failing emissions.

What I've learned over the years (about enclosures anyhow) is that you want to use CRS with a clear zinc finish (RoHS compliant, conductive, corrosion resistant, looks nice)

There are MANY layout tweaks that can reduce radiated emissions too but that can be an art.