Mitigation of radiated EMI from SD Card slot?
Mitigation of radiated EMI from SD Card slot?
(OP)
Anyone have suggestions for physical design of slot that have proven successful in reducing EMI? Assuming that a small grounded door is not an option.
We have experimented with slotted metal fascia plates and with metallized plastic fascia plates that recess the SD Card into a throat. Neither proved hugely successful.
Anything that was tried and worked to mitigate emissions would be helpful.
Thanks, NigelT
We have experimented with slotted metal fascia plates and with metallized plastic fascia plates that recess the SD Card into a throat. Neither proved hugely successful.
Anything that was tried and worked to mitigate emissions would be helpful.
Thanks, NigelT
"You will master any feeling of inadequacy you may be having"
....from my fortune cookie @ the buffet!
RE: Mitigation of radiated EMI from SD Card slot?
Yeah, I know it's not easy.
As for mods associated only with the SD slot, all I can think of is a metal box extending inward from the fascia, surrounding the card for much of its length, possibly flanged and bonded to the fascia.
A simple slot in a flat metal faceplate constitutes a 'slot antenna', basically a dipole of approximately the slot length, and should be a pretty good radiator. I don't know offhand it there's a way to degrade a slot antenna; maybe a different shape?
Mike Halloran
Pembroke Pines, FL, USA
RE: Mitigation of radiated EMI from SD Card slot?
I haven't proven out this idea, simply because the metal door would have been my first suggestion (or a metal flap that can snap down in front of the slot when not in use).
RE: Mitigation of radiated EMI from SD Card slot?
I will check out the metal SD Cards though they look a little like St Steel appliances - "dressed up". They have, I think a plastic frame exposed around the edge but it's hard to see in pictures. And, of course we can't control what brand of card our customers may use.
When we tried the plastic fascia plate with metallized internal paint we actually found the emissions were boosted locally at the card opening. Also several card brands are themselves significant emitters.
"You will master any feeling of inadequacy you may be having"
....from my fortune cookie @ the buffet!
RE: Mitigation of radiated EMI from SD Card slot?
TTFN

FAQ731-376: Eng-Tips.com Forum Policies
Need help writing a question or understanding a reply? forum1529: Translation Assistance for Engineers
RE: Mitigation of radiated EMI from SD Card slot?
It's called a slot antenna.
They can be very effective. ... as you now know.
IRStuff's idea is most likely to be effective, since you have already excluded a door as a solution.
Mike Halloran
Pembroke Pines, FL, USA