Emission (electromagnetic radiation) from an electrical device is inevitable and this radiation is a major interference in the performance of the source object as well as devices that are close to it. Hence, electromagnetic compatibility (EMC) becomes a major factor to control the unintentional generation, propagation, and reception of electromagnetic energy. This electromagnetic noise is produced due to rapid changes in current and voltage, and this is spread through a coupling mechanism. However, this coupling effect can be attenuated at the start or the end of the path through a good EMC design. A small change can reduce both emissions and susceptibility of electromagnetic radiation.
Grounding and Shielding
This method either reduces the emission or diverts the EMI from surrounding devices via an alternative, low-impedance path. Here are some of the EMC design techniques that can be used:
-Grounding is one technique that can minimize the RF effect.Shielded cables can be used to minimize the effect.
-Usually, signal wires are grounded on one or both ends. These are surrounded by an outer conductive layer.
–A conductive metal housing can act as an interference shield. It has sections and RF gaskets that are used at the sections to stop any leakage.
There are even designs to suppress emission and that can be done through one of the following ways:
-Avoiding integration of unnecessary switching operations
-Separation of noisy circuit
-Using the spread spectrum method
-Designing with lower signal level to reduce emission
In order to reduce susceptibility, the following design changes can be done:
-Reduce noise level by designing for operation at higher signal levels
-Fuses, trip switches and circuit breakers
Besides the above-mentioned techniques, you can also avoid antenna structures or incorporate RF chokes and/or RC elements to address emission issues.