Introduction to ANSYS HFSS for Antenna Design

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Chapter 1.1: IntroductionIntroduction to ANSYS HFSS

14. 0 Release

Introduction to ANSYS HFSS for Antenna Design

Chapter 2: Dipole Example

ANSYS, Inc. Proprietary© 2009 ANSYS, Inc. All rights reserved.

February 23, 2009Inventory #002593

© 2012 ANSYS, Inc.2-2 Release 14.0February 1, 2012

• High Frequency Structure Simulator– Full-wave 3D electromagnetic field solver– Industry leading EM simulation tool

• Simulation driven product development• Shorten design cycle• First-pass design success

– Finite element method with adaptive mesh refinement• Provides an Automatic, Accurate and Efficient solution• Removes requirement for manual meshing expertise

HFSS: Powerful Electromagnetic Simulation

Automatic Adaptive Meshing




HFSS: Wide Variety of Antenna Applications

Military Platform IntegrationPhased Arrays

Integrated Mobile Devices Commercial Platform IntegrationBiomedical




• Finite Element Method• HFSS• Efficiently handles complex material and geometries• Volume based mesh and field solutions• Fields are explicitly solved throughout entire volume• Frequency and Transient solutions

• Integral Equations• HFSS‐IE• Efficient solution technique for open radiation and

scattering• Currents solved only on surface mesh• Efficiency is achieved when structure is primarily

metal

• Physical Optics new in v14

• HFSS‐IE• High frequency approximation• Ideal for electrically large, smooth objects• Currents are approximated in illuminated regions and set to zero

in shadow regions• 1st order interactions

Hybrid Solutions

HFSS: Simulation Technologies




• Ansoft Desktop– Advanced ACIS based Modeling– True Parametric Technology – Dynamic Editing

• Advanced boundary conditions– Perfectly matched layers– Floquet ports and Periodic linked boundaries– Layered and Screening impedance boundaries

• Advanced solver technology– Automatic, adaptive conformal mesh generation– Iterative and Direct matrix solver– Higher-order and mixed basis functions– ALPS fast and interpolating frequency sweeps– 3D Finite element and Integral Equation Techniques

as well as Hybrid FEM-IE solutions– Domain Decomposition Methods for very large

problems and arrays– Analytical derivatives for fast design sensitivity

analysis

• Complex materials– Frequency-dependent, anisotropic, non-linear

• Output quantities– Active S-parameters– Antenna trace characteristics (Beamwidth, SLLs)– Near fields and far fields– Field plots throughout geometry

• Design automation– Parametric modeling – Parametric sweeps– Optimizations– Sensitivity and statistical analysis– Distributed solve for high-performance computing

HFSS: Advanced Features for Antenna Design

Screening impedance

-25.00-20.00-15.00-10.00-5.000.005.00

90

60

300

-30

-60

-90

-120

-150-180

150

120

m1

m2

m3

m4

Curve Info lSidelobeY lSidelobeX xdb10Beamwidth(3)dB(DirTheta)

Setup1 : LastAdaptive -5.62 -74.00 61.58

Name Theta Ang Magm1 -74.00 -74.00 -5.62m2 14.00 14.00 6.51m3 50.00 50.00 3.57m4 -10.00 -10.00 3.79

6 7 8 9 10 11 12 13 14Frequency [GHz]

-40

-35

-30

-25

-20

-15

-10

-5

0

Activ

e R

etur

n Lo

ss (d

B)

Ansoft Corporation arrayActive Return Loss

Curve InfodB(ActiveS(P1:1))

Setup1 : Sweep1dB(ActiveS(P2:1))

Setup1 : Sweep1




• Antenna Design Kit– Library of 50+

antennas– Custom antennas– Synthesis feature

HFSS: Advanced Features for Antenna Design

• Dynamic link– Bi-directional link between

circuit solver and HFSS– Incorporates antenna feed

circuits for complete system simulation

Source Design

Target Design

• Data Link– HFSS design can be

used as excitation in a separate HFSS design

– Enables efficient simulation of large and complex geometries

0

Port1 1

2

3

A

V

V

Antenna Input

0 HFSS Model

Ansoft Designe

r




HFSS - Solution Process

Design

Solution Type

Boundaries

ExcitationsMesh

OperationsAnalysis

Solution SetupFrequency Sweep

Creating GeometryGeometry/Materials

Results2D Reports

Fields

MeshRefinement Solve

Update

Converged

Analyze

Finished

Solve Loop

NO

YES

Automatic solution process generates accurate, efficient

solution

Initial Project Setup

Model Setup

Solution Setup

Viewing Results




• Automatic Adaptive Meshing– Finite element method with adaptive mesh

refinement– Provides an Automatic, Accurate and Efficient

solution– Removes requirement for manual meshing expertise

• Meshing Algorithm– Meshing algorithm adaptively refines mesh

throughout geometry– Iteratively adding mesh elements in areas where a

finer mesh is needed to accurately represent field behavior

• Resulting in an accurate and efficient mesh

HFSS - Adaptive Meshing

Convergence Vs. Adaptive Pass

Mesh at each adaptive pass




Voltage

Current0

λ/2

λ/4 λ/4Surrounding air box

Metal Wire

Excitation

Ideal Half Wave Dipole

Far Field Radiation Pattern

Return Loss

Finite element analysis of real half wave dipole antenna using HFSS

HFSS Model of Half Wave Dipole AntennaResonant at 1 GHz

Half Wave Dipole Example




• Launching Ansoft HFSS– To access Ansoft HFSS, click the Microsoft Start button, select Programs, and select the Ansoft, HFSS 14 program

group. Click HFSS 14

• Setting Tool Options– Note: In order to follow the steps outlined in this example, verify that the following tool options are set : – Select the menu item Tools > Options > HFSS Options

• Click the General tab– Use Wizards for data input when creating new boundaries: Checked– Duplicate boundaries/mesh operations with geometry: Checked

• Click the OK button– Select the menu item Tools > Options > Modeler Options.

• Click the Operation tab– Automatically cover closed polylines: Checked– Select last command on object select: Checked– Expand history tree on object select: Checked

• Click the Drawing tab– Edit property of new primitives: Checked

• Click the OK button

Getting Started




• Opening a New Project– If a new project and new design are not already opened, then:

• In HFSS Desktop, click the On the Standard toolbar, or select the menu item File > New.

• From the Project menu, select Insert HFSS Design.

• Set Solution Type– Select the menu item

HFSS > Solution Type• Choose Driven Terminal• Click the OK button

HFSS – Initial Project Setup

AnalysisSolution Setup

Frequency Sweep


Results2D Reports

Fields

Model Setup

Solution Setup

Viewing Results

Design

Solution Type





• Set Solution Type– This section describes how to set the Solution Type. The Solution Type defines the type of results, how the excitations

are defined, and the convergence. The following Solution Types are available:• Driven Modal - calculates the modal-based S-parameters. The S-matrix solutions will be expressed in terms of

the incident and reflected powers of waveguide modes.• Driven Terminal - calculates the terminal-based S-parameters of multi-conductor transmission line ports. The S-

matrix solutions will be expressed in terms of terminal voltages and currents.• Eigenmode – calculate the eigenmodes, or resonances, of a structure. The Eigenmode solver finds the resonant

frequencies of the structure and the fields at those resonant frequencies. • Transient – For calculating problems in the time domain. Applications include simulations with pulsed excitations,

field visualization employing short duration excitation, and time domain reflectometry (TDR).

• Adaptive Mesh Convergence Criteria– Driven Modal – Delta S for single or multi-mode (modal) S-Parameters. – Driven Terminal – Delta S for the single-ended terminal (nodal) S-Parameters. – Eigenmode - Delta F– Transient - Delta S

Solution Type




Ansoft HFSS Desktop

Menu bar

Progress Window

Property Window

Message Manager

ProjectManager

with projecttree

Status bar

3D ModelerWindow

Toolbars

Coordinate Entry Fields




• Ansoft Desktop – Project Manager– Multiple Designs per Project– Multiple Projects per Desktop– Integrated Optimetrics Setup

• Requires License for Analysis

Project Manager Window

Project

Design

Design Results

Design Setup

Design Automation•Parametric

•Optimization•Sensitivity•Statistical

Project Manager Window




HFSS – Model Setup

Design

Solution Type


Frequency Sweep

Results2D Reports

Fields


Solution Setup

Viewing Results

Boundaries

Excitations


Model Setup

Surrounding air box

Metal Wire

Excitation

•Metal Wire – 2 perfectly conducting cylinders with a length of approximately λ/2•Surrounding Air Box – Air volume surrounding antenna element to allow radiation of fields, radiating boundary condition will be applied to outer surface to act as infinite free space•Excitation – Lumped port excitation applied to a rectangle drawn between each arm of dipole to provide an RF excitation to antenna element




• Ansoft 3D Modeler

3D Modeler3D Modeler Window

Graphicsarea Model object3D Modeler

design tree Right Click -Context menu

EdgeVertex

Face




• 3D Modeler Design Tree– The 3D modeler design tree attached to the 3D modeler window displays objects and object history– This tree allows easy navigation to any point in the model history for reference or change to be made

Modeler Tree

Grouped by Material

Material

Object

Object Command History




• Object Properties– All objects have two type of properties that can be viewed. These are Attributes and Commands. Attributes are

properties of the object such as name, material type, color and transparency. Attributes are always accessed by selecting the top level object in the 3D modeler design tree. Properties listed underneath the top level object name are Commands. Commands contain properties of an operation like the size and position of a box.

3D Modeler – Object Properties

Right Click > Properties

Attributes

Commands




3D Modeler – Create a Primitive

• The Coordinate Entry fields allow equations to be entered for position values. – Examples: 2*5, 2+6+8, 2*cos(10*(pi/180)).– Variables are not allowed in the Coordinate Entry Field

• Note: Trig functions are in radians

Point 2

Point 3

Point 1

Grid Plane

Base Rectangle

Point 1

Point 2

Point 3

Coordinate Entry Fields




• Set Model Units– Select the menu item Modeler > Units

• Select Units: cm• Click the OK button

• Set Grid Plane– Select the menu item Modeler > Grid Plane > XY– With this selection, the cylinder will be drawn along the Z-

axis using the current working coordinate system

• Create Dipole Arm– Select the menu item Draw > Cylinder– Using the coordinate entry fields in the lower right hand

corner of HFSS window, enter the center position• X: 0.0, Y: 0.0, Z: 0.1125, Press the Enter key

– Using the coordinate entry fields, enter the radius of the cylinder

• dX: 0.225, dY: 0.0, dZ: 0.0, Press the Enter key– Using the coordinate entry fields, enter the height of the

cylinder• dX: 0.0, dY: 0.0 dZ: 6.6, Press the Enter key

– The properties window will now automatically be displayed showing the Command and Attribute tabs

Create Arm of Dipole Antenna




• Command Tab– The command tab shows dimensions of cylinder drawn, values can be modified from this window at any time as well as

variables added to easily parameterize geometry

• Attributes Tab– Select the Attribute tab from the Properties window.

• For the Value of Name type: Arm_1• For the Value of Material, select the drop down material selection menu by clicking on the current material name

(“vacuum”)– To assign a new material select Edit and browse the material library for “perfect conductor” and select OK

• Select OK on Properties to complete the material assignment

Modifying Properties of Dipole Arm

Material LibraryProperties Window




– Context Menu

– Shortcuts• Since changing the view is a frequently used operation, some useful shortcut keys exist. Press the appropriate

keys and drag the mouse with the left button pressed:– Fit All Ctrl + D– Rotate ALT + Drag or Click Center Mouse Button (click wheel) + Drag

• In addition, there are 9 pre-defined view angles that can be selected by holding the ALT key and double clicking on the locations shown on the next page.

– Pan Shift + Drag– Dynamic Zoom ALT + Shift + Drag or Mouse Wheel

Pan

Rotate AroundModel Center

Dynamic Zoom

Zoom In/Out

Top

Bottom

Right

Predefined View Angles

Left

Rotate AroundCurrent Axis

Rotate AroundScreen Center

Fit All

Fit Selected

Changing the View




Create Second Arm of Dipole Antenna

• View All– Select the menu item View > Fit All > Active View. Or press the

CTRL+D key

• Duplicate the object Arm_1– Select the object Arm_1 that is to be duplicated

• Menu item Edit > Select > By Name…– Choose Arm_1 from Select Object window and press OK– This will highlight the object graphically

– With object Arm_1 selected go to menu item Edit > Duplicate > Around Axis

• Enter Axis X, Angle 180 deg, Total Number 2, press OK

• Press OK to close property window– To fit the view:

• Select the menu item View > Fit All > Active View, Or press the CTRL+D key




Create Air Box

Air Box

Approx. /8

• Create Air box– Select the menu item Draw > Box– Using the coordinate entry fields, enter the Position

• X: -3.75, Y: -3.75, Z: -10.5 Press the Enter key– Using the coordinate entry fields, enter the opposite corner of the base rectangle

• dX: 7.5, dY: 7.5, dZ: 21, Press the Enter key– Select the Attribute tab from the Properties window.

• For the Value of Name type: Air_box• For the Value of Material, select “vacuum” • Click the OK button

– To fit the view:• Select the menu item View > Fit All > Active View, Or press the CTRL+D key




• Set Grid Plane– Select the menu item Modeler > Grid Plane > YZ– With this selection, we will be able to draw a rectangle in the YZ plane

• Create Rectangle– This rectangle will be used later to assign a lumped port excitation– Select the menu item Draw > Rectangle– Using the coordinate entry fields, enter the first corner of rectangle

• X: 0.0, Y: -0.225, Z: -0.1125, Press the Enter key– Using the coordinate entry fields, enter the opposite corner of rectangle

• dX: 0, dY: 0.45, dZ: 0.225, Press the Enter key– The properties window will now automatically be displayed showing the

Command and Attribute tabs• Select the Attribute tab from the Properties window.

– For the Value of Name type: Port_1– Note: No material properties can be assigned to this

object because it a 2D sheet object and only boundary conditions and excitations can be assigned

• Select OK to close properties window

Create Geometry for Port Assignment




• Select the faces of the Air object – Select the menu item Edit > Select > By Name

• Select the objects named: Air_box• Click the OK button

– Select the menu item Edit > Select > All Object Faces

• Add Perfectly Matched Layer (PML)– Select the menu item HFSS > Boundaries > PML Setup Wizard

• PML Setup Wizard: Cover Objects.– Uniform Layer Thickness: 10cm (Approx. /3)– Click the Next button

• PML Setup Wizard: Material Properties.– Minimum Frequency: 1GHz– Minimum Radiating Distance: 3.75cm– Click the Next button

• PML Setup Wizard: Summary– Click the Finish button

Assigning Boundary Conditions




• PML Setup Wizard helps create objects with appropriate material properties

• Input– Uniform Layer Thickness

• Thickness of PML Object Created (recommended > λ/3)– Minimum Frequency

• Minimum frequency that PML will be absorbing– Minimum Radiating Distance

• Distance from radiating object to PML Object

PML Setup

1

2

PML ObjectMinimum Radiating Distance

Uniform Layer Thickness

Air Box

PML Corner Object

Radiating Element




• Assign Excitation– Select the menu item Edit > Select > By Name

• Select the objects named: Port_1• Click the OK button

– Note: You can also select the object from the Model Tree– Select the menu item HFSS > Excitations > Assign > Lumped Port

• Port Name: 1• Conductor: Arm_1_1• Use as Reference: Checked• Highlight Selected conductors: Checked• Click the OK button

– Expand the Excitations in Project Manager• Click on 1. • This will highlight the port that was just assigned

Assigning Port




HFSS – Solution Process

Design

Solution Type


Results2D Reports

Fields


Model Setup

Viewing Results


Frequency Sweep

Analyze

Solution Setup




• Creating an Analysis Setup– Select the menu item HFSS > Analysis Setup > Add Solution Setup

• Click the General tab:– Solution Frequency: 1 GHz– Maximum Number of Passes: 6


Add Solution Setup

Add Solution Setup




• Adding a Frequency Sweep– Select the menu item HFSS > Analysis Setup > Add Frequency Sweep

• Select Solution Setup: Setup1 • Click the OK button

– Edit Sweep Window:• Sweep Type: Interpolating• Frequency Setup Type: Linear Step

– Start: 0.8 GHz– Stop: 1.2 GHz– Step: 0.01 GHz


• HFSS – Frequency Sweep – Discrete – Solves using adaptive mesh at every frequency

• Matrix Data and Fields at every frequency in sweep– Fast - ALPS

• Matrix Data and Fields at every frequency in sweep– Interpolating – Adaptively determines discrete solve

points using the adaptive mesh• Matrix Data at every frequency in sweeps• Fields at last adaptive solution

Add Frequency Sweep

Add Sweep




• Save Project– Select the menu item File > Save As

• Filename: dipole• Click the Save button

• Model Validation– Select the menu item HFSS > Validation Check

• Click the Close button– Note: To view any errors or warning messages, use the Message Manager.

• Analyze– Select the menu item HFSS > Analyze All

Analyze

Validate Analyze All




HFSS – Solution Process

Design

Solution Type


Frequency Sweep



Model Setup

Solution Setup

Results2D Reports

Fields

Viewing Results




• Create Reports– Select the menu item HFSS > Results > Create Terminal Solution Data Report> Rectangular Plot

• Solution: Setup1: Sweep• Domain: Sweep

– Category: Terminal S Parameter– Quantity: St(Port_1_T1, Port_1_T1)– Function: dB– Click New Report button

• Click Close button

Post Processing – Create S-Parameter Report




• Create a Radiation Setup– Select the menu item HFSS > Radiation > Insert Far Field Setup >

Infinite Sphere– Name: ff_2d– Phi: (Start: 0, Stop: 90, Step Size: 90)– Theta: (Start: -180, Stop: 180, Step Size: 2)

• Click the OK button– Note: A radiation setup is required in order to create far-field reports,

this can be done before or after the simulation has been run. The choice of Phi and Theta angles here will result in only cuts in the principal plane.

• Create 2D Radiation Plot– Select the menu item HFSS > Results > Create Far Fields Report>

Radiation Pattern– New Report Window:

• Solution: Setup1: Last Adaptive• Geometry: ff_2d

– Category: Gain– Quantity: GainTotal– Function: dB– Click New Report button


Post Processing – 2D Radiation Plot




• Create a Radiation Setup– Select the menu item HFSS > Radiation > Insert Far Field Setup > Infinite

Sphere– Name: ff_3d– Phi: (Start: 0, Stop: 360, Step Size: 5)– Theta: (Start: 0, Stop: 180, Step Size: 5)

• Click the OK button– Note: We didn’t need to create 2 separate radiation setups, instead we could

have used a single 3D pattern setup and create 2D and 3D plots from the same setup by selecting the correct phi and theta angles to be swept in the report creation window.

• Create 3D Polar Plot– Select the menu item HFSS > Results > Create Far Fields Report> 3D Polar

Plot– New Report Window:

• Solution: Setup1: Last Adaptive• Geometry: ff_3d Note: Make sure to select the correct radiation

setup– Category: Gain– Quantity: GainTotal– Function: dB– Click New Report button


Post Processing – 2D Radiation Plot




• Return to 3D modeler – To return to the 3D modeler window, double click on the design name

• Create Field Overlay– From the 3D Model tree, expand the Planes – From the tree, select the Global YZ – Select the menu item HFSS > Fields > Plot Fields > E > Mag_E

• Solution: Setup1 : LastAdaptive• Quantity: Mag_E• Click the Done button

– Select the menu item HFSS > Fields > Modify Plot Attributes• Select Plot Folder Window, Click the OK button• E-Field Window:

– Click the Scale tab• Scale: Log

– If real time mode is not checked, click the Apply button.• Click the Close button

– To Animate the field plot:• Select the menu item HFSS > Fields> Animate

– Click the OK button

Post Processing – Field Overlay




• Turn of previous field overlay– Select the menu item: View > Visibility > Active View Visibility– Select tab: FieldsReporter uncheck visibility of all plots

• Create Radiation Pattern Overlay– Right click on the 3D modeler window to display context menu– From the context menu select: Plot Fields >Radiation Field…

• Select Visible for the 3D Polar Plot that was created in the previous slide• Set the Scale: 0.1 and select Apply• Select: Close

Post Processing – Radiation Pattern Overlay

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Introduction to ANSYS HFSS for Antenna Design

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