I am working on a PCB that is very crowded, and has high gain amplifiers working between 300kHz and 500kHz
Typically I would use Mu metal or similar for shielding at this frequency, but obviously nobody makes Mu metal PCBs. So I have a choice of solid or hatched pours. External shields are not an option.
I don't have any controlled impedance tracks.
My only worry is the high frequency AC magnetic fields. We use copper mesh shielding in our RF cages, which works rather better than I expected. I suspect this is due to the shorted turns.
I asked a couple of shielding companies, but they don't characterize their meshes for this sort of application.
Can someone point me to data that would indicate whether solid or meshed copper pours would perform better in this situation?
Best Answer
Solid would perform better, all other things being equal, but perhaps not significantly better.
Since the 'holes' in your mesh will be a tiny fraction of a wavelength, the mesh should behave similarly to a thinner (higher resistivity) solid copper layer when measured from a relatively large distance away compared to the 'holes'.
The 'shorted turns' you mention are just eddy currents which will occur in either case.