Any device used to block an RFI signal between its source and a receiver is an electromagnetic interference (EMI) shield.

The measure of this ability to attenuate RFI is Shielding Effectiveness, SE, which is expressed in decibels, dB, the ratio of field strength on one side of the shield to the other side. The figure above shows the relationship between shielding effectiveness (in dB), the amount of attenuation, and attenuation percentage.

Engineering assistance is always available. We will be pleased to help with applications, cross-referencing or complete insertion loss calculations when a custom suppressor is required.