EMVSchirmung

EMV-Schirmung refers to methods and structures used to prevent electromagnetic interference (EMI) by enclosing devices or pathways with conductive or magnetic shields. The aim is to reduce both emitted and received interference to meet electromagnetic compatibility (EMV) requirements.

Shielding effectiveness (SE) is the key performance metric and is typically expressed in decibels. SE depends on material properties such as conductivity and magnetic permeability, on the thickness of the shield, on frequency, and on the quality of seams, joints, and terminations. Openings, gaps, and improper grounding can significantly degrade shielding. Shielding works through a combination of reflection, absorption, and, at higher frequencies, diffraction of electromagnetic energy.

Common shielding structures include conductive enclosures (such as metal housings or Faraday cages), shielded cables with braided or foil conductors, EMI gaskets, shielded connectors, and ferrite cores or beads on cables. Materials range from aluminum and stainless steel to copper, as well as high-permeability alloys for magnetic shielding. For low-frequency magnetic fields, magnetic materials are often used; at higher frequencies, conductive layers are typically more effective, and multi-layer or composite constructions can provide broadband protection.

Design considerations emphasize maintaining a continuous conductive path to ground, minimizing seams and apertures, and using proper EMI gaskets and seals. It is important to control penetrations with filtered feedthroughs, shielded cables, and properly rated connectors. Real-world shielding is validated through chamber measurements and standards-based testing. Common references include IEC 61000-4-x and CISPR 16, which guide measurement setups, while EMI filters and shielding strategies are selected to balance performance with thermal and mechanical constraints.

Applications span consumer electronics, automotive and aerospace systems, medical devices, and industrial equipment, where controlling emissions and susceptibility is essential for functionality and safety.