RF absorbing sheet materials? (5GHz)

[berkeman]

Has anybody used thin RF absorbing sheets or tiles to attenuate RF radiation off of PCB assemblies? I've seen it used many years ago, and I have a 5GHz application that I'd like to try an absorbing sheet on. The PCBA is a few cm on a side, and the sheet or sheets would be applied directly on the side(s)...

 

[berkeman]

This is one of the sheets that I've requested samples of to try out...

http://www.wavexorb.com/products/product_details.php?PN=SN075-081&lang=en

 

[davenn]

Also the sheets / pieces of black foam that is used for anti-static protection of IC's is brilliant for that use

I have even used wedge shaped sections in the end of waveguides on 5 and 10 GHz as a dummy load

Dave

 

[berkeman]

Also the sheets / pieces of black foam that is used for anti-static protection of IC's is brilliant for that use

I have even used wedge shaped sections in the end of waveguides on 5 and 10 GHz as a dummy load

Dave

Huh! I didn't think of that. I have anechoic chamber time scheduled for the end of this week, and will try anti-static foam as an option. That would be WAY cheaper than the commercial sheets. Thanks brother!

 

[davenn]

no probs ... when I looked at that link you gave I wasn't really sure if it was for the same / similar sort of stuff or not ?

 

[berkeman]

It looks like they can tune their sheets for particular frequencies. I'm not sure how they do it, but that's a nice feature. I want low loss in the 2.4GHz-2.5GHz band for 802.15.4 comm, but good loss around the 5GHz second harmonic band where we are having regulatory issues (for out-of-band harmonic energy).

 

[Tolklein]

I second the black foam, it's what our systems use, no idea what it is exactly, but I'll see what I can find out, I know they operate in the 850MHz to 1GHz range.