Getting Started with HFSS 3D Layout: Low Pass
Filter Release 2020 R1 January 2020
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Conventions Used in this Guide
Please take amoment to review how instructions and other useful
information are presented in this guide.
l Procedures are presented as numbered lists. A single bullet
indicates that the procedure has only one step.
l Bold type is used for the following: o Keyboard entries that
should be typed in their entirety exactly as shown. For example,
“copy file1” means the word copymust be typed, then a spacemust be
typed, and then file1must be typed.
o On-screen prompts andmessages, names of options and text boxes,
andmenu com- mands. Menu commands are often separated by carats.
For example, “click HFSS>Excitations>Assign>Wave
Port.”
o Labeled keys on the computer keyboard. For example, “PressEnter”
means to press the key labeledEnter.
l Italic type is used for the following: o Emphasis. o The titles
of publications. o Keyboard entries when a name or a variablemust
be typed in place of the words in ital- ics. For example, “copy
file name” the word copymust be typed, then a spacemust be typed,
and then name of the file must be typed.
l The plus sign (+) is used between keyboard keys to indicate that
you should press the keys at the same time. For example, “Press
Shift+F1” means to press the Shift key and the F1 key at the same
time.
Ribbons, menu bars, and short-cut menus are threemethods that can
be used to see what commands are available in the
application.
l Ribbons are the rectangular area on top of the application window
and contain multiple tabs. Each tab has relevant commands that are
organized, grouped, and labeled. An example of a typical user
interaction is as follows:
"On theDraw ribbon tab, click theBox primitive" means you can click
theBox icon on the Draw tab and execute theBox command to draw a
box.
l Themenu bar (located above the ribbon) is a group of themain
commands of an application arranged by category such File, Edit,
View, Project, etc. An example of a typical user inter- action is
as follows:
"On the Filemenu, click theOpen Examples command"means you can
click the Filemenu and then clickOpen Examples to launch the dialog
box.
l Another alternative is to use the short-cut menu that appears
when you click the right-mouse button. An example of a typical user
interaction is as follows:
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Getting Started with HFSS 3D Layout: Low Pass Filter
Getting Started with HFSS 3D Layout: Low Pass Filter
“Right-click and selectAssign Excitation> Wave Port” meanswhen
you click the right- mouse button with an object face selected, you
can execute the excitation commands from the short-cut menu (and
the corresponding sub-menus).
Getting Help: ANSYS Technical Support
For information about ANSYS Technical Support, go to the ANSYS
corporate Support website, https://www.ansys.com/Support. You can
also contact your ANSYS account manager in order to obtain this
information.
All ANSYS software files are ASCII text and can be sent
conveniently by e-mail. When reporting dif- ficulties, it is
extremely helpful to include very specific information about what
stepswere taken or what stages the simulation reached, including
software files as applicable. This allowsmore rapid and effective
debugging.
Help Menu
To access help from themenu bar, clickHelp and select from
themenu:
l HFSS Contents - click here to open the contents of the help. l
HFSS Search - click here to open the search function of the online
help.
Context-Sensitive Help
To access help from the user interface, do one of the
following:
l To open a help topic about a specificmenu command, pressShift+F1,
and then click the command or toolbar icon.
l To open a help topic about a specific dialog box, open the dialog
box, and then pressF1.
4
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1 - Introduction 1-1
HFSS 3D Layout in ANSYS Electronics Desktop 1-1
Set Up an HFSS 3D Layout Design 1-3
2 - Create the Model 2-1
Insert Layers 2-1
Draw theModel 2-6
Set Up a Planar EMAnalysis 3-1
Set Up Frequency Sweeps 3-3
Explore Disabling Sweeps and Setups 3-6
View theMesh 3-8
View SMatrix Data 4-1
Plot Return Loss 4-3
Revise p2 Excitation and Animate Current Results 4-6
Frequency Animated Far Field Plot 4-13
Getting Started with HFSS 3D Layout: Low Pass Filter
Contents-1
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Contents-2
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Getting Started with HFSS 3D Layout: Low Pass Filter
1 - Introduction This chapter contains the following topics:
l Sample Project – Low Pass Filter l HFSS 3D Layout in ANSYS
Electronics Desktop l Set up an HFSS 3D Layout Design
Sample Project – Low Pass Filter The figure below is a low pass
filter that you will create as an HFSS 3D Layout design and analyze
as a planar EM solution. Themodel consists of three layers, one
signal layer, a dielectric layer, and a ground layer. You will
define the layers, assign a custommaterial to the dielectric, draw
the model, define the ports, and set up the solution.
After solving themodel, you will review the S Matrix results and
plot the return loss and a Smith chart. You will also create a
current density overlay, a far field display, and animate both of
these results.
Figure 1-1: Low Pass Filter Model
HFSS 3D Layout in ANSYS Electronics Desktop HFSS 3D Layout offers
several design simulators for HFSS, Planar EM, SIwave, EMI, and
Nexxim.Within the scope of this guide, we will discuss
thePlanarEMSolution Setup only.
Getting Started with HFSS 3D Layout: Low Pass Filter
Introduction 1-1
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Getting Started with HFSS 3D Layout: Low Pass Filter
Figure 1-2: ANSYS Electronics Desktop – Analysis Setups for
HFSS 3D Layout Designs
EMDesign simulators are the ideal tools for projects that involve
full-wave or radiative effects for multilayered structures. For
example, you can draw the physical layout of a patch antenna or
amil- limeter-wave integrated circuit and then simulate the
electromagnetic properties to display the fol- lowing:
l Radiated electric fields l Basic electromagnetic field quantities
l Characteristic port impedances and propagation constants l Basic
far-field parameters for electromagnetic fields and antennas l
GeneralizedS-parameters, andS-parameters renormalized to specific
port impedances
For more information see the HFSS 3D Layout Simulator in themain
help.
Introduction 1-2
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Getting Started with HFSS 3D Layout: Low Pass Filter
The following sectionswill guide you through the physical design
and EManalysis of a low-pass fil- ter. As you work through this
sequence of HFSS 3D Layout topics, you will learn the
following:
l How to start ANSYS Electronics Desktop and explore the HFSS 3D
Layout tools l How to use the HFSS 3D Layout ribbon, menubar, and
shortcut menu l Terms and concepts essential to the simulation of
an HFSS 3D Layout design l How to add a custom-defined
dielectricmaterial to a design l How to create a report to display
simulation results
Set Up an HFSS 3D Layout Design Before inserting an HFSS 3D Layout
Design into your project, ensure that the ANSYS Electronics Desktop
options are set appropriately for this exercise.
Launch ANSYS Electronics Desktop (EDT):
1. Launch EDT using the desktop shortcut ( ) or
theWindowsStart menu.
There should be an empty project at the top of the Project Manager.
However, if you already had EDT open and closed a previousmodel,
you will have to create a new project (by com- pleting optional
step 2).
2. Optionally (if needed), on theDesktop ribbon tab, click New to
create a new project. 3. Right-clickProjectx at the top of the
Project manager and selectRename. Then, type
LowPassFilter as the new name and pressEnter.
Verify EDT General Options:
4. On theDesktop ribbon tab, click General Options. 5. In the tree
on the left side of theOptions dialog box, expand theGeneral group
and select
theDefault Options subgroup. 6. Ensure thatmm is selected from the
Length drop-downmenu to usemillimeters as the
default length unit. 7. From theOptions tree, select the Layout
Editor> Snapping subgroup. 8. Click Snapping tab, deselectSnap
to grid, and ensure that your selected optionsmatch the
following settings:
Introduction 1-3
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Getting Started with HFSS 3D Layout: Low Pass Filter
Figure 1-3: Layout Editor Snapping Options
9. From theOptions tree, select the Layout Editor> Display
subgroup. 10. In theGrid panel, enter 10 mm forMajor and 1 mm
forMinor, making sure that the unit
used for each ismillimeter (mm), the default setting.
Introduction 1-4
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Getting Started with HFSS 3D Layout: Low Pass Filter
Figure 1-4: Layout Editor Display Options
11. ClickOK to close theOptions dialog box.
Insert an HFSS 3D Layout Design into Your Project:
12. On theDesktop ribbon tab, choose HFSS 3D Layout from the HFSS
drop-down menu.
Alternatively, you can insert an HFSS 3D Layout using either of the
following two options:
l Using themenu bar, clickProject> Insert HFSS 3D Layout Design.
l Right-click the project name at the top of the Project Manager
and choose Insert> Insert HFSS 3D Lay-out Design from the
shortcut menu.
Introduction 1-5
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Getting Started with HFSS 3D Layout: Low Pass Filter
13. If theChoose Technology dialog box appears, clickNone.
Figure 1-5: Choose Technology Dialog Box
The Layout Editorwindow appears.
l All EM designsmust define a process topology (also called a
stackup). l Layout technology files provide a quick way to store
frequently used process topo- logies. For example, an engineer who
frequently uses a specific substrate can pre- specify the correct
materials and stackupswith a single click.
l In this example, you will not use a layout technology file but
will define the topology or stackupmanually.
14. Hide theMessageManager andProgresswindows if either is
currently displayed. l On theViewmenu, you can deselect the
check-boxes forMessage Manager and Progress.
l Alternatively, you can clickHide Messages andHide Progress along
the bottom of the programwindow.
Introduction 1-6
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Getting Started with HFSS 3D Layout: Low Pass Filter
2 - Create the Model The low pass filter model consists of a ground
layer, a dielectric layer, and a signal layer. You will only draw
objects on the signal layer, which you will name t1. In this
section, you will define the stackup layers (topology) of themodel,
draw the geometry of the filter, and assign the excitation
ports.
This chapter contains the following topics:
l Insert Layers l Draw theModel Geometry l Assign the Ports
Insert Layers 1. Access theEdit Layers dialog box by doing either
of the following:
l On the Layout ribbon tab, click Layout dialog. l From themenu
bar, select Layout> Layers.
2. Under Stackup, in theEdit Layers dialog box, deselect the
Laminate mode option. 3. Under Layer, click Insert below to begin
inserting an infinite ground layer, Then, in theAdd
Stackup Layer dialog box, do the following:
Note:
When adding the first layer to the table, the actions of Insert
above and Insert below are identical.
a. Enter g1 in theName text box. b. Choose signal from the Type
drop-downmenu.
Figure 2-1: Inserting Ground Layer (g1)
c. ClickOK to add the layer.
Notice that thematerial copper is automatically assigned to signal
layers.
Create theModel 2-1
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Getting Started with HFSS 3D Layout: Low Pass Filter
4. Tomake theNegative column visible, right-click any one of the
column header at the top of the layer table (such asMaterial, Type,
orName) and select theNegative option, which is off by
default:
Figure 2-2: Showing the Negative Column
5. Set the new g1 layer to be negative by selecting the check-box
in theNegative column.
Note:
Activating this option tells the program that this is a ground
plane layer. Any object you draw on a negative layer becomes a
cutout in the ground layer (conductor removed). However, you will
not be drawing any objects on the g1 layer for this model.
6. Deselect theRough option for this layer if it is currently
selected.
Note:
If theRough option is selected, the surface roughness of the
conductors is taken into account when approximating the impedance
of the signal traces. However, sur- face roughness is ignored for
ground layers. Deselecting this option prevents a warning to that
effect from being encountered when validating themodel and solu-
tion setup.
Create theModel 2-2
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Getting Started with HFSS 3D Layout: Low Pass Filter
7. Insert and define a dielectric layer as follows: a. Right-click
the g1 layer and select Insert dielectric above from the short-cut
menu.
Figure 2-3: Inserting the Dielectric Layer above Layer g1
b. In the new dielectric row that appears in the layers table,
click theName text box and change the name to d1.
c. In the Thickness text box, specify 1.6mm.
Notice that thematerial FR4_epoxy, which is a common printed
circuit boardmaterial, is automatically assigned to dielectric
layers. In the next step, you will change this specification to a
user-definedmaterial.
8. SelectEdit from theMaterials drop-downmenu in the d1 row.
Figure 2-4: Edit Material Command
In theSelect Definition dialog box that appears, do the
following:
a. ClickAdd Material.
TheEdit Materials dialog box appears.
b. In theMaterial Name text box, entermy_d1. c. In theRelative
Permittivity text box, enter 2.2.
Create theModel 2-3
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Getting Started with HFSS 3D Layout: Low Pass Filter
d. Leave all other settings unchanged and clickOK to close theEdit
Material dialog box. e. ClickOK to close theSelect Definition
dialog box.
9. Insert a trace (signal) layer as follows: a. Right-click the
dielectric (d1) layer and choose Insert signal above. b. In theName
column of the new signal row, type t1. c. Select theRough option
for this layer.
10. Ensure that theSolver option is deselected for all layers. You
will not be overriding any of the default solver options.
11. ChooseSelect all from the drop-downmenu in the Layer section at
the bottom-left corner of theEdit Layers dialog box to
simultaneously select all three rows in the table.
Note:
Even if Select all is already showing in this drop-downmenu, choose
it again to actually select all the layers.
12. Ensure that the second checkbox in theAttributes section of the
dialog box is selected to ensure that all objects will be shaded,
as opposed to a wire frame view (outline only):
Figure 2-5: Enable Shading for Drawn Objects
Create theModel 2-4
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Getting Started with HFSS 3D Layout: Low Pass Filter
13. Verify that theEdit Layers dialog boxmatches the following
figure:
Figure 2-6: Edit Layers Dialog Box
Note:
If you did not create the stackup in the correct order, rearrange
the layers by click- ing and dragging the selection handles in the
leftmost column. Drag layer t1 to the top of the list, d1 to
themiddle, and g1 to the bottom.
14. ClickApply and Close to apply the layer definitions and close
theEdit Layers dialog box.
Create theModel 2-5
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Getting Started with HFSS 3D Layout: Low Pass Filter
Draw the Model 1. On the Layout ribbon tab, select t1 from
theActive Layer drop-downmenu:
Figure 2-7: Setting t1 as the Active Layer
2. Draw a rectangle: a. Do either of the following:
l On the Layout ribbon tab, click Draw rectangle. l Using themenu
bar, clickDraw> Primitive> Rectangle.
b. Then in the Layoutwindow, click, move themouse, and click again
to draw a rectangle of any location and size.
c. In the dockedPropertieswindow, ensure that 2Pt Description is
selected, type 0,0 for thePt A value, type 20, 4.6 for thePt B
value, and pressEnter.
Alternative Method of creating the rectangle (using the coordinate
text boxes to specify the precise location and size of the
rectangle while drawing it):
a. After initiating theDraw rectangle command, double-click in theX
coordinate text box on theStatus Bar (located at the bottom of the
ANSYS Electronics Desktop screen) and enter 0.
b. PressTab to move to theY coordinate text box, enter 0 here too,
and pressEnter.
Note:
The Tab key switches between text boxes, while pressingEnter
commits the data to the design. Also note that the first corner of
the rectangle has been placed at the center of the grid per the 0,
0 values for theX andY coordin- ates.
Create theModel 2-6
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Getting Started with HFSS 3D Layout: Low Pass Filter
Figure 2-8: Coordinates of First Corner of Rectangle
c. Complete the rectangle by entering the values of 20 forDelta X
and 4.6 forDelta Y. Then, pressEnter.
Warning:
Be careful not to move themouse while inputting values in the
coordinate text boxes, or the valueswill revert to the cursor
location.
3. Fit the drawing to the Layoutwindow by doing one of the
following: l PressCtrl+D.
l On the Layout ribbon tab, click Fit All. l Using themenu bar,
clickView> Fit Drawing.
4. On the Layout ribbon tab, click Draw rectangle, then define the
second rectangle as fol- lows:
a. Click the lower-right corner of the first rectangle to snap the
first corner of the second rectangle to that point. The cursor
changes to a square shape when the snap point is found.
b. Double-click theDelta X text box and type 2.1. c. Tab to
theDelta Y text box, type -10.5, and pressEnter.
5. On the Layout ribbon tab, click Draw rectangle, then define the
third rectangle as fol- lows:
a. In the coordinate text boxes, type 21.05 for X, 0 for Y, and
pressEnter. b. In the coordinate text boxes, type 21.7 forDelta X,
0.7 forDelta Y, and pressEnter.
6. On the Layout ribbon tab, select Zoom Area from the Zoom
drop-downmenu. Then, click and drag themouse to define a zoom area
that tightly encloses only the right edge of the first rectangle,
the top edge of the second one, and the left edge of the third one.
The display should resemble the following figure:
Create theModel 2-7
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Getting Started with HFSS 3D Layout: Low Pass Filter
Figure 2-9: Zooming into Polygon Area
7. On the Layout ribbon tab, click Draw polygon, then define the
polygon as follows: a. Click the upper-right corner of the first
rectangle. If you let themouse hover briefly
over the target point, the cursor becomes a square and jumps to the
snap point. (The coordinates in the status bar should display 20.0,
4.6.)
b. Click the upper-left corner of the third rectangle (when the
displayed coordinates are 21.05, 0.7).
c. Click the lower-left corner of the third rectangle (when the
displayed coordinates are 21.05, 0.0). Note that the cursor may
become a triangle in this case, since the snap- ping point
corresponds to themidpoint of the second rectangle's top edge
aswell as the end point of two of the third rectangle's
edges.
d. Double-click the lower-right corner of the first rectangle
((when the displayed coordin- ates are 20.0, 0.0).
8. PressCtrl+D to fit the drawing within the Layoutwindow and click
in the background area to clear the current selection.
At this point, your layout should look similar to the following
figure:
Create theModel 2-8
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Getting Started with HFSS 3D Layout: Low Pass Filter
Figure 2-10: Partially Completed Model Layout
9. Copy and paste a duplicate of all objects except for the third
rectangle drawn, as follows: a. PressCtrl+A to select all objects.
b. While holding downCtrl, click the third rectangle drawn to
deselect it. The first and
second rectangle and the polygon should now be selected. c.
PressCtrl+C to copy the selected objects to theWindows clipboard.
d. PressCtrl+V to paste a duplicate set of objects into the Layout
window. The location
of the pasted objects will move as youmove themouse, but do not
click yet. e. Click a point within the Layout window to drop the
objects anywhere that theywon't
overlap the original objects, but keep them selected
afterward:
Figure 2-11: Copy & Paste Operation
Create theModel 2-9
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Getting Started with HFSS 3D Layout: Low Pass Filter
10. On the Layout ribbon tab, click Flip> About Y (or, using
themenu bar, clickDraw> Flip Horizontal).
11. Click on one of the selected objects and drag them so that the
bottom left corner of the second polygon snaps to the bottom right
corner of the third rectangle:
Figure 2-12: Positioning the Mirrored Objects
The result is a set of objects that are symmetrical about the
vertical centerline of the assembly.
12. Clear the current selection and pressCtrl+D to fit themodel
within the Layout window. The model should look like the following
figure:
Figure 2-13: Model with Mirrored Objects Properly Positioned
13. On the Layout ribbon tab, click Draw rectangle, then define the
final rectangle as fol- lows:
a. In the coordinate text boxes, enter 29.3 for X, 0 for Y, and
pressEnter. b. In the coordinate text boxes, enter 5.3 forDelta X,
-10.5 forDelta Y, and pressEnter.
14. PressCtrl+A to select all objects in themodel.
Create theModel 2-10
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Getting Started with HFSS 3D Layout: Low Pass Filter
15. On the Layout ribbon tab, click Unite.
The rectangles and polygons are united into a single object, and
your layout should look sim- ilar to the following figure:
Figure 2-14: United Model Geometry
Note:
It is not mandatory to unite the individual shapes.Where they
exactlymeet each other, the solver will treat them as a contiguous
object. However, uniting them pro- duces a simpler model and
eliminates the possibility of accidentally dragging one shape out
of its proper position.
16. Click the united object to select it. Then, in the
dockedPropertieswindow, change theName to Filter and
pressEnter.
17. Click Save, which is located on all ribbon tabs.
Assign the Ports 1. CreatePort1:
a. PressE to begin theSelect Edgesmode.
l Alternatively, on the Layout ribbon, choose Select Edges from the
selec- tionmode drop-downmenu (immediately below the Layers dialog
command):
Create theModel 2-11
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Getting Started with HFSS 3D Layout: Low Pass Filter
Figure 2-15: Choosing Selection Mode Via the Layout Ribbon
Tab
l Or, from themenu bar, clickEdit> Select Edges. b. Click the
left edge of the first (leftmost) rectangle to select it.
Figure 2-16: Selecting Edge for Port 1
c. On the Layout ribbon tab, click Create edge port.
Note that Port1 appears in the layout editor and is also listed in
the Project Manager under Excitations.
Alternativemethods of adding a port. After selecting the
edge:
l In the Project Manager, right-clickExcitations and chooseAdd
Port. l Using themenu bar, clickDraw> Port> Create. l Or,
right-click in the Layout window and choosePort> Create from the
short- cut menu.
Create theModel 2-12
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Getting Started with HFSS 3D Layout: Low Pass Filter
2. CreatePort 2: a. Click the right edge of the rightmost rectangle
to select it.
Figure 2-17: Selecting Edge for Port 2
b. On the Layout ribbon tab, click Create edge port. 3. RenamePort
1:
a. In the Project Manager, under Excitations, right-clickPort1 and
chooseRename. b. Type p1 and pressEnter.
4. RenamePort 2 (this time you will use an alternativemethod): a.
In the Project Manager, under Excitations, clickPort2 to select it.
b. In the dockedPropertieswindow, change thePort value (row 1,
column 2) to p2 and
pressEnter.
Create theModel 2-13
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Getting Started with HFSS 3D Layout: Low Pass Filter
3 - Set Up Solution and Analyze This chapter contains the following
topics:
l Set Up a Planar EMAnalysis l Set Up Frequency Sweeps l Explore
Disabling Sweeps and Setups l View theMesh l Explore DynamicMesh
Updates l Run the Analysis
Set Up a Planar EM Analysis Each set of solution parameters to be
solved by ANSYS Electronics Desktop is listed as a setup
underAnalysis in the Project Manager. To add a new solution setup
to this project using basic, ini- tial meshing tools, do the
following:
1. On theSimulation ribbon tab, click PlanarEM (Add Planar
EMSolution Setup).
Alternatively, complete this action in one of the following two
ways:
l Right-clickAnalysis in the Project Manager and clickAdd Planar EM
Solution Setupfrom the shortcut menu.
l Using themenu bar, selectHFSS 3D Layout> Solution Setup>
Add Planar EM Solution Setup.
2. When thePlanarEMSetup dialog box appears, select Fixed Mesh,
underMesh Selection in theGeneral tab.
Set Up Solution and Analyze 3-1
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Getting Started with HFSS 3D Layout: Low Pass Filter
3. Enter 5GHz in theSolution Frequency text box.
Figure 3-1: PlanarEM Setup Dialog Box
4. ClickOK to accept the setup.
The Planar EMSetup dialog box closes and theEdit Frequency Sweep
dialog box appears. You will define the frequency sweep in the next
topic.
Note:
For more information on setting up an HFSS simulation, seeAdd HFSS
Solution Setup in the product Help.
Set Up Solution and Analyze 3-2
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Set Up Frequency Sweeps To set up sweeps, you can choose to add
either an interpolating sweep or a discrete sweep. You will define
both types of sweeps. The procedural steps for setting up each
sweep type are described below:
Add an Interpolating Sweep:
1. An interpolating sweep can be added in any of the following
ways: l The sweep appears automatically after you create a solution
setup. l Select the analysis setup in the Project Manager (in this
case,PlanarEMSetup 1).
Then, on theSimulation ribbon tab, click Sweep (Set Up Frequency
Sweeps). l Select the analysis setup in the Project Manager. Then,
using themenu bar, click HFSS 3D Layout> Solution Setup> Add
Frequency Sweep.
l In the Project Manager, expand theAnalysis folder,
right-clickPlanar EM Setup 1, and clickAdd Frequency Sweep from the
shortcut menu.
Any one of these actions opens theEdit Frequency Sweep dialog box
associated with a Planar EM solution setup.
In the case of this exercise, theEdit Frequency Sweep dialog box
should already be open as a result of completing the addition of a
Planar EM solution setup in the previous topic.
2. Select Interpolating from theSweep Type drop-downmenu. 3. Select
Linear Count from theDistribution pull-downmenu. 4. Enter the
following sweep parameters:
l Start = 1.5 GHz l Stop = 5GHz l Points = 201.
TheEdit Frequency Sweep dialog box should now look like the
following figure:
Set Up Solution and Analyze 3-3
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Figure 3-2: Edit Frequency Sweep Dialog Box – Interpolating
Sweep
Set Up Solution and Analyze 3-4
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5. ClickPreview to display theSweep Pointswindow:
Figure 3-3: Sweep PointsWindow – Interpolating Sweep
6. Close theSweep Pointswindow. 7. ClickOK to add the interpolating
sweep and close theEdit Frequency Sweep dialog box.
Add a Discrete sweep:
8. In the Project Manager (under Analysis), right-clickPlanar EM
Setup 1, and clickAdd Fre- quency Sweep
9. ChooseDiscretefrom theSweep Type drop-downmenu. 10. Select
Linear Count in the pull-downmenu of theDistribution column. 11.
Enter the sweep parameters:
l Start = 1.6GHz l Stop = 2.6GHz l Count = 11.
Set Up Solution and Analyze 3-5
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12. Click thePreview button to display the Sweepwindow:
Figure 3-4: Sweep PointsWindow – Discrete Sweep
13. Close theSweep Pointswindow. 14. SelectGenerate surface
current, underOptions in theEdit Frequency Sweep dialog box.
Note:
For discrete sweeps, optionally generating surface currents enables
you to view currents and calculate far field effects at multiple
frequencies in later post-pre- cessing steps. For interpolating
sweeps you can optionally save surface current data for only the
last adaptive pass of the solution frequency. For fixedmesh ana-
lyses, you cannot save surface current data.
15. ClickOK to add the discrete sweep and close theEdit Frequency
Sweep dialog box.
Explore Disabling Sweeps and Setups ANSYS Electronics Desktop lets
you to disable/enable sweep and setup definitions
independently.
Disable or Enable a Sweep Definition:
Set Up Solution and Analyze 3-6
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To enable/disable a frequency sweep definition, right-click the
sweep in the Project Manager and chooseEnable Sweep Analysis
orDisable Sweep Analysis, whichever option is present:
Figure 3-5: Disable Sweep Analysis Option
Note:
You can also disable a sweep by double-clicking it in the Project
Manager (or right-click- ing and selectingProperties from the
shortcut menu) to open theEdit Frequency Sweep dialog box. In the
upper-right corner of this dialog box, deselect theEnabled option
and clickOK to apply the change. (To reactivate the sweep, simply
re-open theEdit Fre- quency Sweep dialog box, select theEnabled
option, and clickOK.)
Disable or Enable a Setup Definition: To enable/disable a setup
definition, right click the setup in the Project Manager and choose
Enable Setup Analysis orDisable Setup Analysis, whichever option is
available:
Set Up Solution and Analyze 3-7
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Figure 3-6: Disable Setup
Note:
You can also disable an analysis setup by double-clicking it in the
Project Manager (or right-clicking and selectingProperties from the
shortcut menu) to open thePlanarEM Setup dialog box. Below theSetup
Name text box, deselect theEnabled option and click OK to apply the
change. (To reactivate the setup, simply re-open thePlanarEMSetup
dia- log box, select theEnabled option, and clickOK.)
When you disable an analysis setup, any sweep associated with it
has no effect, even though the sweep is still enabled.
View the Mesh You can view the layout of the design within the
Layoutwindow in a number of planar or 3D views. If you've closed
the Layoutwindow or opened other windows in front of it, such as a
2D report plot, you can quickly return to the Layoutwindow as
follows:
l From themenu bar, clickHFSS 3D Layout> Layout Editor. This
commandwill reopen the window if it has been closed or bring it to
the front if it's already open.
l Or, when the Layoutwindow is still open but hidden by other
windows, select it from theWin- dowmenu to bring it to the
front.
In the Layoutwindow, you can view themesh in either of two
ways:
Set Up Solution and Analyze 3-8
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l In the Project Manager, click to select the setup (such
asPlanarEMSetup 1). Then, from the menu bar, clickHFSS 3D
Layout> Solution Setup> Pre-Process Geometry>
Display.
l In the Project Manager, right-click the setup and
selectPre-Process Geometry> Display from the shortcut
menu.
Either of the preceding two options displays a 3D mesh on themodel
in the Layout window. The mesh display honors layer visibility;
that is, themesh will not be displayed on a layer that is not vis-
ible. If there are self-intersectingmesh edges, these are
highlighted in bold yellow.
To hide themesh, repeat the command from either access point and
toggle off theDisplay option. However, for now, leave themesh
visible and proceed to the next topic. You can hide themesh
later.
Explore Dynamic Mesh Updates In the previous topic, you learned how
to display themesh. The Layout editor allows you to change the
shape of the objects you've drawn by select them and then clicking
and dragging grips on the edges (such asmidpoint and endpoint
grips). This feature enables you to freelymove, stretch, com-
press, or skew object shapes. Additionally, you can add or remove
objects from themodel. By default, themesh is not dynamically
updated when you change the geometry in any of these ways.
Therefore, after adding, deleting, or altering any geometry, you
would have to refresh the displayed meshmanually using one of the
follow methods:
l In the Project Manager, right-click the analysis setup (such
asPlanarEMSetup 1) and choosePre-Process Geometry> Refresh from
the shortcut menu.
l Select the analysis setup in the Project Manager. Then, from
themenu bar, clickHFSS 3D Layout> Solution Setup> Pre-Process
Geometry> Refresh.
Important:
The consolidation of surfaces into a conformal mesh is skipped for
dynamic and tolerant meshing, including for light weight
geometries. This can lead to overlapping surfaces in SBR+
simulations. The user should carefully avoid overlapping surfaces
or objects as SBR+ can produce unexpected results.
Dynamic Updates: By enabling theDynamic Updates feature, themesh
will automatically refresh whenever you alter the geometry in
anyway. You can enable this feature in either of two ways:
l In the Project Manager, right-click the analysis setup (such
asPlanarEMSetup 1) and choosePre-Process Geometry> Dynamic
Updates from the shortcut menu.
l Select the analysis setup in the Project Manager. Then, from
themenu bar, clickHFSS 3D Layout> Solution Setup> Pre-Process
Geometry> Dynamic Updates.
Either of these actions toggles the state of theDynamic Updates
option. That is, the feature is enabled if currently disabled, and
the feature is disabled if currently enabled.
Set Up Solution and Analyze 3-9
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Feel free to experiment by displaying themesh, enablingDynamic
Updates, and then adding new geometry or distorting existing
geometry to see themesh refresh itself. Afterward, use the Undo
command, which is available onmultiple ribbon tabs, to revert to
the correct model configuration. Be careful not to undo tomany
operations, or your sweeps, analysis setup, or port definitionswill
be undone. If you do go too far, click Redo to restore the
desiredmodeling and setup steps.
Important:
It is a good idea to save themodel first and avoid saving it during
the experiment. In this way, you can close the alteredmodel
(without saving it) and reopen the saved version if
necessary.
When finished, deactivate thePre-Process Geometry> Display
option to hide themesh.
Run the Analysis 1. To sequentially run all analysis setups and
associated frequency sweeps that exist in the
design, take one of the following actions:
l On theSimulation ribbon tab, click Analyze. l From themenu bar,
clickHFSS 3D Layout> Analyze. l In the Project Manager,
right-clickAnalysis and chooseAnalyze from the shortcut menu.
Alternatively, you can run a single sweep: In theAnalysis branch of
the Project Manager, right-click the appropriate sweep and
chooseAnalyze from the shortcut menu.
Set Up Solution and Analyze 3-10
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Figure 3-7: Analyzing a Single Sweep
2. ClickShow Progress in the status bar at the bottom of the
programwindow to display the solution progress (if the window is
not already displayed).
3. Check the status while the analysis is running.
The following additional actions are possible:
l While the simulation is running, you canPause orAbort it through
the shortcut menu that appears when you right-clicking in
theProgresswindow.
l TheClean Stop command completes the computation of the current
frequency point before stopping the analysis.
l To alter the priority of a particular simulation, right-click
theProgresswindow, click Change Priority, and then select the
appropriate setting (Highest, Above Normal, Normal, Below Normal,
or Lowest Priority).
Figure 3-8: Changing the Priority of the Analysis Solution
Note:
Altering the priority of a solution can be useful when you
aremultitasking on the computer. It can help to free up resources
from a computationally intens- ive application so that other
programs perform adequately. Conversely, it can prevent less
important programs from excessively slowing down the more intensive
application.
Set Up Solution and Analyze 3-11
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4 - Evaluate the Results (Post-Pro- cessing)
Use the post-processing capabilities of ANSYS Electronics Desktop
to display the results of a sim- ulation. You can also use the
export features to save the analysis data (and an equivalent
circuit) in various industry-standard file formats.
The topics for this section include:
l View SMatrix Data l Plot Return Loss l Plot a User DefinedGraph l
Revise p2 Excitation and Animate Current Results l Frequency
Animated Far Field Plot
View S Matrix Data You can review the scatter matrix (S Matrix)
data at all sweep frequencies or at a selected fre- quency as the
solution progresses. You can also review Y and ZMatrix data
andmore. Here, you will look at the S Matrix data for all
frequencies in Sweep 1, as follows:
1. In the Project Manager, right-clickSweep1, and selectResults>
Matrix data.
TheSolutions dialog box appears.
2. Ensure that only theS Matrix option is selected under theProfile
tab.
Evaluate the Results (Post-Processing) 4-1
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3. Select theDisplay All Freqs. option. Your results should be
similar to the following figure:
Figure 4-1: Solutions Dialog Box – Sweep 1 S Matrix Data
4. Select the Format tab and then choose the desired data format
from the drop-downmenu (for example,Magnitude/Phase(deg),
dB/Phase(deg), Real, or Imaginary).
5. Select theExport tab and clickExport Matrix Data.
TheExport Network Data Solution dialog box appears.
a. Select the preferred file format (Save as type) – for example,
Touchstone(*.sNp) or Neutral Model Format (*.nmf).
b. Optionally, customize the File name, if desired. c. The default
save location is the same folder where themodel resides. However,
you
can navigate to an alternative folder is desired. d. ClickSave or
clickCancel to abort the operation.
Evaluate the Results (Post-Processing) 4-2
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6. To export the circuit as an equivalent SPICE model,
clickEquivalent Circuit Export.
Note:
SPICEmodels require solution data at DC (0Hz) conditions, so a
warningmes- sage is encountered for this sweep.
a. Select the desired location, format, and other equivalent
circuit options. b. ClickOK to save the exportedmodel orCancel to
abort the operation.
7. To see run time data pertaining to the analysis, click
theProfile tab. 8. Close theSolutions dialog box.
Plot Return Loss To create a report:
1. First, open theReport dialog box by using one of the following
threemethods:
l On theResults ribbon tab, click Standard Report> 2D. l Using
themenu bar, clickHFSS 3D Layout> Results> Create Standard
Report> Rectangular Plot.
l In theProject Manager, right-clickResults and chooseCreate
Standard Report> Rectangular Plot from the shortcut menu.
TheReport dialog box openswith the Trace tab selected.
2. Plot the return loss: a. From theSolution drop-downmenu,
selectPlanar EM Setup 1 : Sweep 1. b. In theCategory, Quantity, and
Function lists, selectS Parameters, S(p1, p1) and
dB, respectively. c. ClickNew Report and then clickClose.
Evaluate the Results (Post-Processing) 4-3
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Figure 4-2: S-Parameter Plot, dB(S(p1,p1)) - Return Loss
For additional details about formatting the plot (for example,
labeling the axes and changing the trace color) see theGenerating
Reports and Postprocessing section of the help.
Plot a Smith Chart Next, you will display a Smith chart for S(p1,
p1). The Smith chart is a convenient means of sim- ultaneously
displayingmultiple parameters (such as impedance, reflection
coefficients, scattering parameters, constant gain contours,
andmore). It is a useful graphical aid for electronics engineers
working in the radio frequency disciplines. The chart was invented
by Phillip H. Smith
1. On theSimulation ribbon tab, click Standard Report> Smith
Chart.
TheReportdialog box openswith the Trace tab selected.
Evaluate the Results (Post-Processing) 4-4
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Note:
Aswith the previous plot (Return Loss), this chart and other plot
commands can also be accessed from other locations (HFSS 3D
Layoutmenu andProject Man- ager: Results shortcut menu).
2. From theSolution drop-downmenu, selectPlanar EM Setup 1 : Sweep
1. 3. In theCategory, Quantity, and Function lists, selectS
Parameters, S(p1, p1), and
<none>, respectively. 4. ClickNew Report andClose.
The Smith Chart appears:
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Figure 4-3: Smith Chart
Revise p2 Excitation and Animate Current Results Before creating an
overlay of the current results and animating it, you will alter the
edge port defin- ition for port p2. The default configuration
applies an identical 1 volt magnitude excitation at 0 degrees phase
angle to both of the ports that you added (p1 and p2). You will now
set the p2 excit- ation to 0 volts, essentiallymaking p1 the input
of the low pass filter and p2 the output for the pur- pose of the
overlay.
To revise the p2 excitation:
1. In the Project Manager, under Excitations, double-clickp2.
TheEdge Port Definition dialog box appears:
2. InPost Processing Settings section, enter 0V and 0deg,
respectively, for theMagnitude andPhase values.
Evaluate the Results (Post-Processing) 4-6
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Figure 4-4: Edge Port Definition Dialog Box – Port p2
The following controls are also available:
Port Definition settings:
l PortName specifies the port being defined l Terminal Name
controls the name of the terminal l Reference specifies the
reference used by the port l Calibration Zo equivalent to the Full
Port Impedance of the port and expressed in Ohms
Planar EM settings:
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l Type of port l Ignore Reference allows you to chooseUse Port
Solver l Use Port Solver should be selected if you want the
characteristic impedance and propagation constant for the port to
be calculated. The gap source is automatically cal- ibrated for
greater accuracy.
l Use Default should be selected if, instead of the Port Solver,
you want the default set- ting to be used (expressed in
Ohms).
HFSS section:
Post Processing settings:
l Magnitude expressed in Volts (V) l Phase expressed in degrees l
Post Process Port allows you to specify theRenormalize Impedance
andDeembed Distance settings
l Renormalize Impedance expressed in ohms l Deembed Distance
expressed inmm l Deembed Gap Port Inductance specifies that the
inductance of the port is cal- culated and cached as part of the
solution data for subsequent use. During post pro- cessing a list
of the ports to deembed is used to calibrate the network
data.
Note:
For more information, seeDeembedding in the help.
3. When all settings are as desired, clickOK to close the dialog
box.
Note:
Alternatively, the followingmethod is convenient for multi-port
designs. You can right-clickExcitations in the Project Manager and
selectPort Excitations from the shortcut menu. ThePort Excitations
dialog box appears, in which you can modifymultiple port
excitations.
Evaluate the Results (Post-Processing) 4-8
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Figure 4-5: Edit Port Excitations Dialog Box
Note:
Renormalization is ignored if it is set to zero, but de-embedding
is still honored. The following warningmessage is produced for all
ports with a zero post-processing renormalization impedance:
Zero impedance on port '<arg1>' is ignored; renormalization
will by skipped for this port.
Display and Animate the Currents:
4. In the Project Manager, right-clickField Overlaysand selectPlot
PEM Fields> Mag_Sru- faceJ.
TheCreate Field Plot dialog box appears.
Note:
The only Solution available for selection isPlanar EM
Setup1:Sweep2, since only the discrete sweep type has the option to
output currents.
5. In the Intrinsic Variables section, select 2.1GHz from the F
(frequency) pull-downmenu. This is the frequency that most closely
corresponds to the point of minimum return loss on the S Parameter
plot.
Evaluate the Results (Post-Processing) 4-9
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6. Accept the remaining options and clickDone.
TheSelect Geometry dialog box appears, where you specify on which
layers you wish to overlay the current results.
7. Select the t1 layer and clickOK.
The current overlay should resemble the following figure:
Figure 4-6: Surface Current Overlay @ 2.1 GHz – t1 Layer
8. In the Layoutwindow, double-click within the current overlay
legend to access the J Surf plot settings.
9. In theColor map tab, choose Temperature from theSpectrum
drop-downmenu:
Evaluate the Results (Post-Processing) 4-10
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Figure 4-7: J Surf Plot Settings – Color map Tab
10. Select theScale tab andmake the following changes: a. Specify
21 forNum. Divisions b. Select the Log option to produce a
logarithmic scale. c. SelectUse Limits. d. ForMin, specify 0.05. e.
ForMax, specify 26.
Figure 4-8: J Surf Plot Settings – Scale Tab
11. In the Project Manager, under Field Overlays> J Surf,
right-clickMag_SurfJ1 and click Animate.
TheCreate Animation Setup dialog box appears.
Evaluate the Results (Post-Processing) 4-11
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12. Specify the following animation settings: a. Ensure that Single
Variable andPhase are selected from theSwept Variable(s)
pull-downmenus. b. In theStart, Stop, andSteps text boxes, enter
0deg, 360deg, and 37, respectively.
These settingswill result in an animation with 10 degree phase
increments.
Figure 4-9: Setup Animation Dialog Box
13. ClickOK. A control panel opens, and the animation begins:
Figure 4-10: Animation Dialog Box
14. You can use the animation controls to pause, restart, reverse,
or change the speed of the animation.
Evaluate the Results (Post-Processing) 4-12
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15. In the Layoutwindow, use the various tools to Zoom, Rotate, or
Pan the animation.
The resulting animation should resemble the one shown below:
Figure 4-11: Resulting Current Animation
16. In theAnimation dialog box, clickClosewhen finished.
Frequency Animated Far Field Plot Far fields are not usually of
interest when designing a filter, but the procedure is shown here
for ref- erence. Current outputs are required as the basis of far
field computations. So that the currents are saved, and the
currents and fields results are available for you to plot, one of
the following two con- ditionsmust bemet:
l Run a discrete sweep with theGenerate surface current option
selected in theSweep setup. In this case, you can specifymultiple
discrete frequency points and will have the cur- rents and fields
available for all specified frequencies. Aswith the current
animation, you can define the frequency at which you view the far
field results. Additionally, you can animate far field results
based on the available frequencies. That is, the video time line
progresses from one frequency to the next (as opposed to
progressing through the range of phase angles as the basis of the
animation).
l Run an adaptivemesh or advanced adaptivemesh analysis with
theSave currents for last adaptive pass option enabled in
theAnalysis setup. In this case, the current and field results are
only available for the last adaptive pass of the specified solution
frequency.
In order to plot far field results, you have to define an Infinite
Sphere far field setup underRadiation in the Project Manager.
Evaluate the Results (Post-Processing) 4-13
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Define an Infinite Sphere and Plot the Far Field Results:
1. In the Project Manager, right-clickRadiation and choose Insert
Far Field Setup> Infinite Sphere.
The Infinite Sphere Setup dialog box appears:
.
Figure 4-12: Infinite Sphere Setup Dialog Box
2. Accept the default setup and clickOK to add the far field
setup.
3. On the Results ribbon tab, click Far Fields Report> 3D
Polar.
TheReportwindow appears. Notice that the Solution andGeometry
parameters are already set with the only available choices that
provide far field results:PlanarEMSetup 1 : Sweep 2 and Infinite
Sphere 1, respectively. Also, theCategory, Quantity, and Function
settings have defaulted to Far Field, Etotal, and <none>,
respectively, which are the desired settings for this report.
4. Select the Families tab and then click the elipsis button
( ) in theEdit column of the Families table.
Evaluate the Results (Post-Processing) 4-14
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5. In the pop-up dialog box that appears, select the frequency,
2.1GHz, which corresponds most closely to the point of minimum
return loss:
Figure 4-13: Choosing the Frequency for the Far Field Plot
6. ClickNew Report and then clickClose.
Note:
You can also access this command in the following alternative
ways:
l Right-clickResults in the Project Manager and chooseCreate Far
Fields Report> 3D Polar Plot from the shortcut menu.
l Using themenu bar, clickHFSS 3D Layout> Results> Create Far
Fields Report> 3D Polar Plot.
The Far Field Plot 1window appears, and the far field pattern is
displayed. Rotate, zoom, and/or pan for a good view point of
themodel:
Evaluate the Results (Post-Processing) 4-15
ANSYSElectromagnetics Suite 2020 R1 - © ANSYS, Inc. All rights
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affiliates.
Getting Started with HFSS 3D Layout: Low Pass Filter
Figure 4-14: Far Field Plot (Etotal)
Overlay the Far Field Pattern on the Model Geometry: To better see
how the far field pattern relates to the low pass filter geometry,
overlay the pattern on themodel in the Layout window, as
follows:
7. UnderResults in theProject Manager, right-clickFar Field Plot 1
and selectOverlay Vis- ibility.
8. Adjust themodel viewpoint as desired. Themodel layout and
overlay should resemble the fol- lowing figure:
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reserved. - Contains proprietary and confidential
information of ANSYS, Inc. and its subsidiaries and
affiliates.
Getting Started with HFSS 3D Layout: Low Pass Filter
Figure 4-15: Far Field Pattern Overlay
Note:
The plot legend and the color contours applied to the trace layer
of themodel still correspond to the surface current plot created
earlier. Optionally, to avoid con- fusion, you could
right-clickMag_SurfaceJ1, under Field Overlays> J Surf in the
Project Manager, and deselectPlot Visibility in the shortcut menu.
This action hides the J Surf color contour and the associated
legend.
Frequency Animate the Far Field Plot:
9. Use theWindowmenu to select the Far Field Plot 1window, bringing
it to the foreground. 10. Right-click in the Far Field Plot 1window
and chooseView> Animate.
TheCreate Animation Setup dialog box appears:
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ANSYSElectromagnetics Suite 2020 R1 - © ANSYS, Inc. All rights
reserved. - Contains proprietary and confidential
information of ANSYS, Inc. and its subsidiaries and
affiliates.
Getting Started with HFSS 3D Layout: Low Pass Filter
11. Ensure that the settings in the dialog boxmatch the following
figure and then clickOK.
Figure 4-16: Setup Far Field Animation with Frequency as Sweep
Variable
The Animation control panel appears and the far field plot
animation begins to play:
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ANSYSElectromagnetics Suite 2020 R1 - © ANSYS, Inc. All rights
reserved. - Contains proprietary and confidential
information of ANSYS, Inc. and its subsidiaries and
affiliates.
Getting Started with HFSS 3D Layout: Low Pass Filter
Figure 4-17: Far Field Plot 1 Animation
12. Use the animation controls to pause, restart, reverse, or
change the speed of the animation. 13. In theAnimation dialog box,
clickClosewhen finished.
14. Save the project and exit ANSYS Electronics Desktop.
Congratulations, you've completed theHFSS 3D Layout: Low Pass
Filter exercise.
Evaluate the Results (Post-Processing) 4-19
ANSYSElectromagnetics Suite 2020 R1 - © ANSYS, Inc. All rights
reserved. - Contains proprietary and confidential
information of ANSYS, Inc. and its subsidiaries and
affiliates.
Table of Contents
HFSS 3D Layout in ANSYS Electronics Desktop
Set Up an HFSS 3D Layout Design
2 - Create the Model
Set Up Frequency Sweeps
View the Mesh
View S Matrix Data
Frequency Animated Far Field Plot