What is Shielding in PCB?
Shielding in PCBs is when you use conductive or magnetic materials to protect electronic components from electromagnetic interference (EMI) that comes from outside. EMI can mess up how the circuit works, which can cause data problems, signal problems, or even make the device stop working. Shielding helps stop or change the electromagnetic waves so the circuit keeps working the way it should.
What is the most common metal being used as an RF shield?
- Electric Field Shielding: This involves blocking electric fields with conductive materials that are grounded. It is effective in preventing the coupling of electric charges from external sources to the circuit components.
- Magnetic Field Shielding: For magnetic fields, materials with high magnetic permeability are used to absorb and redirect the magnetic lines of flux, thus protecting the circuit.
- Electromagnetic Shielding: This type combines both electric and magnetic shielding techniques to protect against electromagnetic radiation. It typically uses materials that can block or attenuate electromagnetic waves.
What are the common materials used for PCB shielding?
Different materials are used for PCB shielding depending on the specific requirements of the application. Here’s a table summarizing some common materials and their properties:
| Material | Properties | Applications |
|---|---|---|
| Copper | High conductivity, malleable | General-purpose EMI shielding |
| Aluminum | Lightweight, cost-effective | Consumer electronics |
| Nickel Silver | Corrosion-resistant, solderable | RF shielding cans |
| Mu-metal | High magnetic permeability | Magnetic shielding |
| Soft Iron | Easily magnetized, cost-effective | Magnetic shielding, power electronics |
How does shielding reduce electromagnetic interference (EMI)?
Shielding is what you do to reduce EMI. You either reflect or absorb electromagnetic waves. Conductive materials reflect the energy, while materials with high magnetic permeability absorb magnetic energy. You want to shield your components from EMI, but you also want to prevent your device from emitting electromagnetic radiation that could interfere with other devices.
What is the most common metal being used as an RF shield?
Nickel silver is generally considered the best material for RF shielding because it has excellent conductive properties and is resistant to oxidation. It is widely used in RF shielding cans, which are commonly used in telecommunications and high-frequency applications.
