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High-performance EM simulation software
Technological leadership since 1992
Complete Technology for 3D EM
260 employees
Worldwide support network
CST – COMPUTER SIMULATION TECHNOLOGY | www.cst.com
Getting Started / Tutorials
The introductory books are a good
starting point to learn the workflow of the
CST STUDIO SUITE® products.
All books are available as PDF documents
in the "Documentation" subfolder of your
CST installation.
CST – COMPUTER SIMULATION TECHNOLOGY | www.cst.com
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Tutorials
Step-by-Step tutorials are available for CST MICROWAVE STUDIO®
and CST EM STUDIO®.
CST – COMPUTER SIMULATION TECHNOLOGY | www.cst.com
Examples Overview
Many pre-calculated examples are available.
Antenna Calculation Examples
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Online Help
Online help documents can be accessed in the "Help" section. It contains:
- Highlights and New Features
- Tutorials and Examples
- Complete Documentation of all Features, Dialogs, VBA Language, etc.
CST – COMPUTER SIMULATION TECHNOLOGY | www.cst.com
Online Help
In almost all dialogs there is a link to the online help documents
which provides you with extensive help for all settings.
Linked page of the online help
Transient solver main dialog
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Online Help
You can find detailed explanations for many warnings and error
messages in the online help.
Just click on the link in the message window.
CST – COMPUTER SIMULATION TECHNOLOGY | www.cst.com
Quick Start Guide
File  Options Preferences  Open Quick Start Guide
The Quick Start Guide
helps new users to make
all settings necessary to
run a simulation model.
Most of the settings are
applied automatically by
the project templates.
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Cylindrical Horn Antenna (8 – 12 GHz)
units: inch
waveguide: 1.0 in x 0.5 in x 0.5 in
aperture radius: 1.0 in, length: 0.25 in
shell thickness: 0.01 in (outside)
monitors: E-field, H-field & far field at 10 GHz
CST – COMPUTER SIMULATION TECHNOLOGY | www.cst.com
New Projects - Project Templates
Project templates are the preferred way to customize CST STUDIO
SUITE® automatically for a certain type of application.
Your already defined project
templates are listed in the
section "Project Templates".
If you haven't defined a project template for your
application click on "Create a new project" to create
one.
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New Project Template - Horn
 At the beginning, choose "Create Project" to create a new
project.
 This starts the configuration wizard in order to help you to
choose the appropriate module, main project settings and result
recorders for the particular application.
 We choose
Microwave & RF
Antennas
Waveguide (Horn, Cone, etc.)
The recommended solvers for the selected workflow
are T, I and F. We choose the Time Domain solver.
 Change the dimensions to inch.
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New Project Template - Horn
Apply Frequency settings and set 3D field monitors.
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New Project Template – Summary Horn
 Finally, verify your settings for the template and save it.
 Save the file as ‘Horn_antenna.cst’.
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Common User Interface
Ribbon Bar
Primary
Window
Navigation
Tree
Parameter List
Message
Window
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Primitives
Cylinder
Torus
Cone
Sphere
Rotation
Brick
Elliptical
Cylinder
Extrusion
Hints:
 Press the tab-key to
enter a point
numerically.
 Press backspace to
delete a previously
picked point.
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View Options
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"Rectangle zoom"
allows to zoom in a rectangular domain.
Change the view by dragging the mouse while pressing the left button and a key.
 ctrl - rotation
 shift – in-plane rotation
 ctrl+shift – panning
Some other useful options are:
 spacebar – reset view structure
 shift+spacebar – zoom into selected shape
 mouse wheel – dynamic zoom to mouse pointer.
Default views are available in a drop down menu.
Top view
Perspective
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Views can be saved and restored.
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Picks - Basic
Pick a point, an edge or a face in the structure.
Coordinates of picked point are shown in 3D view.
Picked Point
Edge length is shown in 3D view.
or
S
Pick corner point,
edge or face (s)
Picked Edge
Picked Face
Hints:
 Press "s" to activate all pick
tools.
 To pick a point by given
coordinates, press "p" and
the tab-key.
 Picking an element twice
unselects it.
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Coordinate System
 The working coordinate system (WCS) allows the use of context
dependent coordinates.
 Use
to switch on/off the WCS.
 Use
to rotate and move the WCS.
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Coordinate System
 Alternatively, use
move the WCS.
and the left mouse button to rotate and
Translation. Drag the axis
of the principal coordinate.
Rotation. Drag the ring segment
around the principal axis.
 Multiple transforms can be performed by clicking "Apply" (or
pressing “Return”) between the single steps.
CST – COMPUTER SIMULATION TECHNOLOGY | www.cst.com
Coordinate System
The WCS can be aligned, e.g., with a point, an edge, or a face.
Align the WCS
with a point
Align the WCS
with an edge
Align the WCS
with a face
Press "w" to align the WCS with the currently selected object.
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Boolean
Boolean operations can be applied to two or more shapes to create
more complex structures.
Sphere
Brick
Intersect
Brick * Sphere
Add
Brick + Sphere
Subtract
Brick - Sphere
Boolean insert
Sphere / Brick
Brick / Sphere
CST – COMPUTER SIMULATION TECHNOLOGY | www.cst.com
Horn Antenna – Construction (I)
Define a brick (1.0 x 0.5
x 0.5 in) made of PEC.
Define a cylinder (outer radius: 1.0
in, height: 0.25 in) made of PEC.
Pick face.
Align the WCS with the
face.
Move the WCS by 2.0 in.
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Horn Antenna – Construction (II)
Pick two opposite faces.
Perform a loft.
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Horn Antenna – Construction (III)
Perform a
Boolean add.
Select multiple objects
(ctrl or shift + left mouse button).
Shell solid: 0.01 in
(outside).
Pick two outer faces.
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Definition of Ports
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Available Port Types
Ports for S-Parameter Computation
Discrete Ports
Waveguide Ports
(Lumped Elements)
(2D Eigenmodes)
Input: Knowledge of TEM Mode and
line impedance is required.
Output: Voltage and current
Discrete ports can be used for TEMlike modes (cutoff frequency = 0),
not for higher order modes.
Input: Area for eigenmode solution
Output: Pattern of E- and H-field,
line impedance,
propagation constant
Waveguide ports provide a better
match to the mode pattern as well as
higher accuracy for the S-parameters.
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Discrete Ports
Current Port
S-Parameter Port
Voltage Port
Current source with internal
resistance. Realizes input
power of 1W (peak).
Wires
Stripline
Microstrip
Coplanar waveguide
CST – COMPUTER SIMULATION TECHNOLOGY | www.cst.com
Discrete Edge Port Definition
Pick two points,
or
pick one point and a face,
or enter coordinates directly (not recommended).
Select port type
and impedance.
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Discrete Face Port Definition
Pick two edges
or
one edge and a face.
Select port type
and impedance.
CST – COMPUTER SIMULATION TECHNOLOGY | www.cst.com
Port Definition – Closed Structures
Typically, waveguide ports are defined based on a geometric object. Use the
pick tools to select a unique port plane.
The port size is equal to the smallest rectangular area which includes all picked objects.
CST – COMPUTER SIMULATION TECHNOLOGY | www.cst.com
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Port Definition – Open Structures
1. Pick face.
2. Enter port menu.
3. Adjust additional
port space using k
and h.
The extension factor k varies
in a range of 5 – 10, typically –
depending on the ratio w/h, εr
and the frequency.
CST – COMPUTER SIMULATION TECHNOLOGY | www.cst.com
Horn Antenna Port Definition
Pick point
inside corner.
Define a waveguide port.
Pick edge.
Define the port on the internal profile.
CST – COMPUTER SIMULATION TECHNOLOGY | www.cst.com
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Boundary Conditions and Symmetry Planes
EM boundaries are
defined by the chosen
antenna template.
Image theorem can be
applied using symmetry
planes to reduce the
overall size of the
calculation domain,
thus speeding-up the
simulation.
CST – COMPUTER SIMULATION TECHNOLOGY | www.cst.com
Meshing Overview
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How to Get a Good Mesh?
1. Use Project Templates
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For several classes of applications (e.g. antennas, PCB boards,
etc.) there are some common properties for a "good" mesh.
Project templates apply some basic settings for the particular area
of application, including global mesh settings.
2. Use Automatic Default Settings
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Make use of automatic settings to let the software choose the
most appropriate algorithm (e.g. order of curved elements).
3. Use Adaptive Mesh Refinement
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Typically the most efficient way to get a refined mesh is using the
automatic mesh refinement which refines the initial mesh
wherever needed according to solver error estimators.
CST – COMPUTER SIMULATION TECHNOLOGY | www.cst.com
Mesh Generation - A Typical Workflow
Automatic
Refinement
Mesh
Groups
no
yes
Project
Template
This adjusts the global mesh
properties to values which we
found to be a good starting point
for a certain area of application.
Global Mesh
Settings
Optimize the global mesh settings
for the geometry of your model.
Perform
Simulation
Results
Automation
Start the solver and perform a
convergence study (e.g. using
adaptive mesh refinement).
Simulations and mesh studies
provide insight about the
dependency of the results on the
mesh settings.
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Mesh View
Mesh lines in one
mesh plane are shown
in the 3D view.
View mesh.
Mesh controls are
displayed in the mesh
view.
Information about mesh plane.
The total number of mesh cells is
also displayed in the status bar.
Corner
Correction
Snap lines
CST – COMPUTER SIMULATION TECHNOLOGY | www.cst.com
Global Settings (I)
Absolute and frequency
dependent settings to
determine the largest
mesh step.
Settings to limit the
size of the smallest
mesh step.
CST – COMPUTER SIMULATION TECHNOLOGY | www.cst.com
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Global Settings (II)
“Cells per wavelength" is based on
the upper limit of the frequency
range.
Thus, increasing the upper frequency
limit usually leads to a finer mesh.
“Cells per max model box edge" is
based on the dimensions of the
computational domain.
The maximum cell size is calculated
by dividing the largest edge of the
model bounding box by this number.
CST – COMPUTER SIMULATION TECHNOLOGY | www.cst.com
Global Settings (III)
Maximum mesh cell size:
Refinement in an area filled by the structure is possible in global
mesh settings (previously only via local mesh properties).
The structure bounding box defines refinement area.
CST – COMPUTER SIMULATION TECHNOLOGY | www.cst.com
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Global Settings (IV)
Minimum mesh cell size:
Absolute or relative values are possible.
Fraction of maximum cell
Absolute value
CST – COMPUTER SIMULATION TECHNOLOGY | www.cst.com
Mesh Groups
 Local mesh settings can be applied to single
objects by defining a mesh group and assigning the
object to the specific group, e.g. per drag&drop.
 The maximum mesh step width can be defined for
each coordinate direction in a mesh group.
 Pre-defined groups are available for
 "Excluding from Simulation" and
 "Excluding from Bounding Box".
Solid1 is
ignored in the
simulation but
considered for
the mesh.
Only the sphere is
considered for
bounding box creation.
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Online Help – PBA and TST
PBA
TST
Whenever a mesh cell cuts more than two metallic material boundaries, the cell
is filled with PEC material (staircase cell). Often such cells do not influence the
simulation result much, but if they introduce shortcuts this might be critical.
CST – COMPUTER SIMULATION TECHNOLOGY | www.cst.com
Mesh View
Mesh properties
TST at work!
Global mesh settings are defined by the chosen antenna template.
CST – COMPUTER SIMULATION TECHNOLOGY | www.cst.com
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Transient Solver: Start Simulation
The accuracy defines the
steady-state monitor.
The simulation is finished
when the electromagnetic
energy in the computational
domain falls below this level.
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Analyze 1D Results
Port signals
Power\Excitation [1]
S-parameters
Energy
Specific extra 1D Results
are directly calculated
due to the chosen
project template.
CST – COMPUTER SIMULATION TECHNOLOGY | www.cst.com
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Analyze 2D/3D Results
Port information:
 cut-off frequency
 line impedance
 propagation constant
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Electric Field at 10 GHz
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Farfield at 10 GHz
Different Plot type can be chosen from the Farfield Plot ribbon.
The Linear Directional polarization is plotted in 3D using the
Ludwig 3 coordinate system. The orientation of the E field vector
and the propagation directions are indicated in the plot.
CST – COMPUTER SIMULATION TECHNOLOGY | www.cst.com
Polar Plot for Farfield at 10 GHz
The Polar plot is obtained for E and H plane by selecting different
Cut Angles.
Phi=0
Phi=90
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Comparing Polar plots
The polar plots can be compared for different cut planes by
copying them as 1D results using Farfield Plot properties.
CST – COMPUTER SIMULATION TECHNOLOGY | www.cst.com
Tips & Tricks for an Accurate Farfield
Tip 1: Choose sufficient accuracy.
The accuracy level in the T-solver should be -40 dB.
For larger frequency bands (e.g. 0-3 GHz) or bad radiation it is
better to use -60 dB so that the E- and H-fields on the bounding
box do not suffer from FFT/DFT truncation errors.
CST – COMPUTER SIMULATION TECHNOLOGY | www.cst.com
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Tips & Tricks for an Accurate Farfield
Tip 2: Set appropriate boundary conditions.
The ”open (add space)“ boundary condition ensures λ/4
space at the center frequency. For lower frequencies (bigger λ)
the space needs to be increased accordingly.
CST – COMPUTER SIMULATION TECHNOLOGY | www.cst.com
Tips & Tricks for an Accurate Farfield
Tip 3: Check the energy balance.
At 4.5 GHz the farfield may be inaccurate.
Farfield values become inaccurate, if S-parameter balance ≈1
(no power is radiated). In this case directivity and gain are
calculated from dividing ≈0/0, which is numerically critical.
A good measure for total radiated power is: (1 - balance).
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Parameterization (I)
2*r1
Change outer radius
value to variable r1.
CST – COMPUTER SIMULATION TECHNOLOGY | www.cst.com
Parameterization (II)
Outer diameter 2*r1
Select solid, then
right-click and
select Properties.
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Result Processing Templates (Shift+P)
Farfield and Antenna Properties
Define gain(theta) at phi=0.
Postprocessing templates provide a convenient way to
calculate derived quantities from simulation results.
Each template is evaluated for each solver run.
CST – COMPUTER SIMULATION TECHNOLOGY | www.cst.com
Result Processing Templates (Shift+P)
General 1D
Define max. of gain (theta)
Read the online help to learn more
about the postprocessing in CST MWS.
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Parameter Sweep - Settings
Define a new parameter sweep.
Sequence from 1 to 1.5 with 3 samples for
the parameter r1.
1
2
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Parameter Sweep - Settings
The 1D Results (e.g. S-Parameters) will be stored parametrically.
The Result Templates will be returned in the “Tables” folder.
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Parametric 1D Plot
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Parameter Sweep - Table Results
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