EMC Intra-Cavity

EMC simulation result example

One of the most common tasks in EMC is to understand how one installed device that is emitting EM energy will affect the operation of other devices on the platform.

The first step is usually to create a large table that lists all the sensitive devices on the platform. For the column, the known emitter frequencies and intensities for all the devices are listed. On the rows, the known victim frequencies and intensities that will cause each device to malfunction are listed. Next, for each emitter/victim pair, the EMC team can quickly assess if there are potential issues.

However, just because one source device is emitting at a certain frequency and intensity does not necessarily mean that it will upset another victim device that is sensitive to that same frequency and intensity. In many cases, the two devices are installed at different locations on the platform. By the time EM energy reaches the victim, it may be attenuated to a level that will not cause a problem.

The best way to determine how the emission level has been reduced near the victim is to determine the transfer function from the emitter source location to the victim location. This can be determined by either testing or simulation.

Testing can be an expensive proposition. Further, testing may be impossible if the platform is still being developed and does not exist for testing yet.

Therefore, it is important to have validated simulation tools that can accurately predict the transfer function from the emitter locations to the victim locations.

Cody Weber, Senior Scientist of EMA has done such validation to show that simulation and testing can have a good correlation. The simulation used EMA3D version 4.0. EMA3D is a finite-difference time domain solution of Maxwell’s Equations. One example plot of the E-fields in the enclosure is shown in the figure above.

The full report is given below:


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