What happens to electromagnetic waves when they penetrate an EMI shield?

When electromagnetic waves penetrate an EMI (Electromagnetic Interference) shield, they undergo a process that generally leads to their weakening. An EMI shield is typically designed to prevent electromagnetic interference by blocking, reflecting, or absorbing these waves.

As the waves encounter the shield, some of their energy is absorbed by the material, which converts the energy into heat and reduces the intensity of the waves that can penetrate through. Additionally, the shield may also reflect some part of the waves, but the key aspect is that the penetration results in a net loss of intensity, leading to a diminishment in strength.

This weakening is crucial in applications involving sensitive electronic equipment where protecting against external electromagnetic interference is necessary for maintaining functionality and performance. The design of the shield, including its materials and thickness, dictates the level of attenuation experienced by the waves.