Electronics > Beginners

cable shield to PCB?

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Zeyneb:
Hi there,

Maybe this topic is already discussed but I haven't been able to find it here.

Considering a round multiple conductor cable with a shield. Either aluminum foil or that mesh of tiny non-insulated wires. What is a professional way to connect the shield specifically to a PCB? That PCB I'm going to design myself, so the options are open. The signal wires I know how to deal with.

I like the design of shielded modular connectors like RJ-45/ethernet. Where you fold the shield back and then crimp a C shape conductor around it.

Would there be some crimp terminals for this? The cable I have specifically has an OD of 5mm. For the PCB connection I'd prefer to have it as low-profile as possible.

Thanks in advance for your suggestions!

radiolistener:
the shielding is not easy task. If you want cable with a good shielding, then it should use at least two isolated shield layers and RF chokes.

It all depends on the frequency and interference type. The most complicated interference type is a near region magnetic field.


The professional way to connect the shield to a PCB is to keep wave impedance between shield and central wire constant across connection and equals to the cable impedance. It allows to eliminate reflections, radiation and sensitivity to interference and can be done with using special geometry and dielectric with specific electromagnetic properties. If it's really important, you can use EM simulation software to design proper geometry for frequency and bandwidth of your needs.

I recommend you to use existing standard connectors, because they already designed for specific impedance used in coax cables. For example if your RF power is less than 100W and you want a cheap and compact solution, you can use SMA connectors. For higher power you can use N connectors.

Zeyneb:
Ok, but I meant in a more practical sense. What terminals can you buy to make that connection in the first place?

radiolistener:

--- Quote from: Zeyneb on May 04, 2024, 04:34:58 pm ---Ok, but I meant in a more practical sense. What terminals can you buy to make that connection in the first place?

--- End quote ---

it depends on your needs. I like SMA connectors, because they are compact. But they have their cons, like small power limit and a smaller number of connection cycles. N type can handle more power and more reliable, but it is more massive. BNC is more easy to connect, but it is less reliable.

So all connectors have their pros and cons and you're needs to select it according to your requirements.

mag_therm:
Search " Shielded Back Shell with metal pcb receptacle"   .... Is that  the style ?

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