Power Splitter simulation with CST

Workflow Example Microstrip Power Splitter

Purpose: Optimize the structure such that the reflection is minimal at 6 GHz.

CST MWS - Standard Workflow 

 Choose a project template.

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 Create your model. 

parameters + geometry + materials

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 Define ports.

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 Set the frequency range.

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Specify boundary and symmetry conditions.

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 Define monitors.

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 Check the mesh.

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 Run the simulation.

Microstrip Power Splitter 11.308

5.2 0.635

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Units: mm, GHz

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Frequency Range: 0-8 GHz

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Substrate: 11.308 mm x 5.2 mm x 0.635 mm, permittivity εr=9

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Height of Metallization: 0.017 mm

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Chamfer Edge Width: 0.8 mm

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Electric Boundaries

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E-field, H-field, and Power Monitors at 6 GHz

New Project Template At the beginning, choose “File”

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“New” to create a new project.

For an existing project you may choose “File”

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“Select Template”.

The project templates customize the default settings for particular types of applications.

Units & Background Material Units

Background Material

Those settings have been set correctly by the project template.

Microstrip Power Splitter Construction (I)

Define a brick and define a new material “substrate”.

Microstrip Power Splitter Construction (II)

Pick the midpoint of the top edge.

Align the WCS with the picked point.

Microstrip Power Splitter Construction (III) Define the profile of the microstrip line.

Enter the polygon points.

Please note that a text (ASCII) file containing the polygon data can be directly loaded into CST MWS.

Microstrip Power Splitter Construction (IV)

Preview of the metallization

Final metallization

Microstrip Power Splitter Construction (V)

Pick the short edge.

Chamfer the edge (chamfer width: 0.8 mm).

Microstrip Power Splitter Construction (VI)

Select the metallization in the tree view.

Mirror and copy the metallization.

Microstrip Power Splitter Construction (VII) Pick the small faces of the metallization.

Pick faces.

Define a variable “move” and set move=1. Offset the picked faces using the parameter "move".

Port Definition (I)

Pick the points at the upper corner of the metallization. Then, pick the midpoint of the lower edge of the substrate.

Port Definition (II)

Define port 1.

Port Definition (III)

Pick face of the metallization.

Port Definition (IV)

Similarly define port 3.

Define port 2.

Set Frequency Range

Set the frequency range.

Boundary Conditions Check boundary conditions.

Those settings have been set correctly by the project template.

3D Field Monitors Add field monitors for E-field, H-field, and power flow at 6 GHz.

Mesh View (I) Please keep the default mesh settings.

Mesh for x-y-plane (press )

Global Mesh Properties

Mesh View (II)

Mesh for x-z-plane (press

)

Mesh for y-z-plane (press

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Set S-Parameter Symmetries Use S-parameter symmetry to reduce the simulation time.

Select symmetrical S-parameters and click on “Set Symmetry”.

Start the Simulation Time Domain Solver

Analyze 1D Results

Please note that the minimum of S11 is currently at approx. 7.8 GHz.

Analyze 2D/3D Results

Port Information: •

Mode type

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Line impedance

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Propagation constant

E-Field & H-Field at 6 GHz

The plots can be obtained using the “clamp to range” option.

Surface Currents & Power Flow at 6 GHz