Do RFI and EMI Start with a Circuit

Both RFI and EMI cause problems for electronic devices everywhere. Natural and human-made sources cause the problem. Considering the growing prevalence of RFI and EMI in the modern world, engineers must actively avoid issues caused by interference. An engineer’s best solution for dealing with these problems includes EMI and RFI shielding

Any circuitry or systems run the risk of generating EMI, which often have differing levels of susceptibility. Some of the biggest cause of EMI includes smart devices, cellular towers, and house-hold appliances. Wireless computer networks and satellites orbiting earth also generate RFI and EMI. The above devices have in common that most of them include microprocessors, microcontrollers, electromechanical relays, switching power supplies, and transmitters.

Designers seem to be fighting an endless battle against radio and electromagnetic interference. This problem is not escapable because EMI occurs in the circuit and becomes apparent in the power supply, inputs, outputs, and ground. The problem is made worse as noise moves through either capacitive, direct, or inductive conducted couplings. This creates a closed-loop that forms between the ground plan and tracers. The loop also creates inductance in the current path that causes multiple AC signals to share the same path. The loop is considered an RFI or EMI antenna.

EMI Shielding

EMI and RFI shielding are important parts of the design of electronics. Without active blocking of harmful EMI and RFI, electronic devices cease to function properly. In some cases, this can be annoying, but in the case of medical equipment, it could mean the difference between life and death

• Material Options for RFI Shielding: Three Popular Metals
  Not all EMI shields are built the same, which means that shields need to be custom constructed depending on the application and design of an electronic device.
• Using EMI Shielding to Reduce Unwanted Noise
• Three Common EMI Shielding Materials