how much a metal sheet can reduce Electromagnetic noise?

Hello board, I want to reduce electromagnetic noise in my PCBs. Ideally I should enclose them in a faraday cage but I can't because the PCBs have some thermal sensetive elements like JFETs and JFET input OpAmps and for retaining precision I need good thermal ventilation over this PCB but I thought maybe a conductive metal sheet like copper or aluminum between my sensitive board and noise source helps. I barely recall somewhere I read that even an aparture of wrong size in a faraday cage can destroy usefulness of faraday cage let alone having five sides of this cage completely open. so can someone answer me if placing a metal sheet between noise source and my sensitive board can help and what would be extent of usefulness of this sheet. I will be very grateful if someone can direct me to a reference on this issue.
Thanks a lot.

You might consider contacting Laird Technologies about various shielding techniques. There are others to chose from as well.

w*w.lairdtech.com


There are numerous facets to the problem and slots in the wrong place can compromise your effort to shield.

You might want to consider a screen with numerous small holes or a shield that is also a heat sink or pipe.

You might also consider burying sensitive circuits in your PCB for better shielding.

Good Luck.