EMC Box - CST2013 MWS Examples

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General Description

This example shows the EMC (electromagnetic compatibility) calculation of a metal box with a slot and a coaxial feed. The electric field outside the metal box in a distance of 3 meters is of interest in this example.

Structure Generation

The structure is generated using basic bricks and cylinders. It consists of a metal housing filled with air. On top of the housing a coaxial feed is mounted off-center.

The inner conductor of this coax line is connected to a thin cylindrical wire which is terminated by a 47 Ohm resistor (lumped element) at the ground of the box. A slot in the metal housing is modeled by a brick of vacuum material.

Mesh Setup

The local mesh properties of the slot in the housing are changed to guarantee at least 3 mesh lines at the slot. Due to the thin elements of the structure, the lines per wavelength settings of the global mesh properties are set to 13.

Solver Setup

A waveguide port at the coaxial feed is defined as excitation source. The boundary conditions were set to open (add space) in all directions except the upper y-direction (Ymax). In this direction the boundary conditions were set to open, since the presence of the coaxial feed already guarantees some extra space in this direction.

Additional surrounding space was added in the upper y-direction manually in order to make the input port internal with respect to the computational domain and to mininize the port's effect on the farfield computation. This extra space can be specified in the "Background Properties" dialog.

Multiple farfield monitors over the given frequency range are defined using the macro Home: Macros Solver Monitors and Probes Broadband Field Monitors.

Post Processing

The scattering parameters are calculated automatically during the simulation and can be accessed in the folder 1D Results. The farfields at the different frequencies can be accessed in the Farfields folder.

Using the macro Home: Macros Results EMC Calculate Broadband EMC-norm allows the calculation of the electric field at a distance of three meters and ten meters over a broadband frequency range.

Note:

For more information about macros and the corresponding built-in macro language please refer to the VBA overview page.