An EMI (Electromagnetic Interference) gasket functions by preserving the continuity of electrical current across discontinuities or gaps in a shielding enclosure. This continuity is essential for effective shielding against external and internal electromagnetic interference sources, which can compromise an electronic device’s performance.
Example of EMI Gasket Functionality: Electromagnetic Leakage Prevention
There are two primary paths through which electromagnetic leakage can occur:
- Direct Leakage Through the Gasket Material:If the gasket’s conductivity is lower than the shield’s, electromagnetic energy can directly penetrate the gasket material.
- Leakage at the Gasket-Shield Interface:Leakage can also occur at the interface between the gasket and the shield, especially if air gaps are present.
To counteract these leakage paths, the EMI gasket is designed to extend the shield’s material properties across its gaps, thereby minimizing electromagnetic interference.
When Should EMI Gaskets Be Used?
Several conditions necessitate the need for EMI gaskets for basic functionality. Understanding when to employ these tools ensures the safe and optimal function of electronics. Below, we highlight when EMI gaskets cannot be ignored.
- Prevent Electromagnetic Interference:EMI gaskets are critical in environments where the integrity of electronic communication or operation is paramount, whether to protect sensitive electronic equipment from external EMI sources or to contain EMI within a device to prevent interference with other devices.
- Seal Against Environmental Factors:These gaskets provide EMI shielding and are used in scenarios where an environmental seal is required to protect against factors such as dust, moisture, or other contaminants. This dual-purpose capability is particularly valuable in reducing costs and assembly time.
- Custom Shielding Applications:In instances where off-the-shelf EMI shielding solutions are inadequate, custom-designed gaskets to fit specific profiles, sizes, and configurations are needed. This is crucial in specialized industrial, military, medical, or consumer electronics applications where standard solutions do not meet the unique shielding requirements.
- High-Performance Requirements:In situations demanding shielding effectiveness of > 85dB attenuation from 20 MHz to 10 GHz and electrical resistance of < 0.05 Ohms/Sq, indicating a need for high-performance shielding against a broad range of frequencies and effective grounding or electrical continuity.
- Variable Temperature Environments:EMI gaskets are essential in environments experiencing wide temperature ranges, specifically between -40 °F (-40 °C) and 158 °F (70 °C), as indicated by the service temperature specifications. This ensures the gasket’s performance remains consistent across different operating conditions.
- Applications Requiring Specific Mechanical Properties:Where the mechanical properties such as compression deflection and compression set within specified temperature ranges are critical for ensuring the gasket maintains its integrity and effectiveness over time under various mechanical stresses and environmental conditions.
These conditions and applications underline the versatility and necessity of EMI gaskets in providing effective electromagnetic shielding while meeting specific environmental, mechanical, and custom design requirements across various industries and applications.
Partner with JEMIC for custom EMI Solutions
Dealing with EMI is becoming more difficult with time because of the rapid increase in technology and the shrinking of many electronic devices. Knowing how to shield electronics adequately should be left to the professionals: us. We are problem solvers and designers who can help you overcome obstacles in your next production run. Give our talented team a call today.