EMI

What Is EMI?

EMI (Electromagnetic interference), also known as radio-frequency interference (RFI), refers to the disruption of electronic devices and systems caused by external electromagnetic fields (EMFs). These undesirable electromagnetic disturbances can degrade electronics performance, malfunction, or cause complete system failures.

Key Causes of EMI

EMI can be caused by a variety of natural and man-made sources:

• Electrical Equipment: Devices such as motors, transformers, and power supplies can emit electromagnetic fields that interfere with electronic and networking systems.

• Wireless Devices: Devices operating on similar frequency ranges, such as wireless routers, cordless phones, and Bluetooth devices, can cause radiated EMI.

• Poor Grounding: Improper grounding can lead to differences in potential that create noise, resulting in EMI.

• Environmental Factors: Natural phenomena like lightning can also produce EMI, although this occurrence is more sporadic.

For data centers specifically, internal equipment often generates the most EMI, although external sources like nearby electrical railway tracks, airports, or telecommunications towers can also pose risks.

What Are the Effects of EMI?

The impact of EMI on electronic systems can be profound, particularly in environments like data centers:

• Hardware Degradation: Uncontrolled electromagnetic fields can cause voltage spikes in cables, leading to electrical noise and degradation of hardware such as servers and storage devices.

• Network Issues: EMI can cause remote receivers to miss data packets, requiring retransmissions and creating network congestion.

• Critical Failures: Low-frequency EMI can severely impair the functionality of hardware, potentially erasing data on storage devices like hard disks and solid-state drives (SSDs).

Types of EMI

EMI can propagate through different pathways, each having unique characteristics and mitigation strategies:

Classification by EMI Sources

EMI can be categorized based on its origin, which includes man-made EMI and natural EMI.

Classification by Propagation Pathways

EMI can also be classified based on how it propagates, which includes conducted EMI, adiated EMI, and coupled EMI.