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Welcome to the2002 Ansoft HFSS/Ensemble

Users’ Workshop

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An Introduction To HFSS OptimetricsTM

OptimetricsTM can take control of your model to achieve performance improvements over initial designs

Lawrence UnterbergerMatt CommensHF Applications EngineersAnsoft Corporation

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Agenda

w HFSS Overview

w What is OptimetricsTM

w Optimetrics Flow

w Example Results

w Optimization of a Patch Antenna

w Conclusion

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What Is HFSS

w HFSS (High Frequency Structure Simulator) is a high-performance full-wave electromagnetic (EM) field simulator for arbitrary 3D volumetric passive device modeling. It integrates simulation, visualization, solid modeling, and automation in an easy-to-use environment where solutions to your 3D EM problems are quickly and accurately obtained. HFSS employs the Finite Element Method (FEM), adaptive meshing, and brilliant graphics to give you unparalleled performance and insight to all of your 3D EM problems. Ansoft HFSS can be used to calculate parameters such as S-Parameters, Resonant Frequency, and Fields.

Leadframe

Uniform Transmission

lines

Via hole With Solder

Microstrip Meander line

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w Package Modeling – BGA, QFP, Flip-Chip

w PCB Board Modeling – Power/Ground planes, Mesh Grid Grounds, Backplanes

w Silicon/GaSa - Spiral Inductors, Transformers

w EMC/EMI – Shield Enclosures, Coupling, Near- or Far-Field Radiation

w Antennas/Mobile Communications – Patches, Dipoles, Horns, Conformal Cell Phone Antennas, Quadrafilar Helix, Specific Absorption Rate (SAR), Infinite Arrays, Radar Cross Section (RCS), Frequency Selective Surfaces (FSS)

w Connectors – Coax, Transitions

w Waveguide – Filters, Resonators, Transitions, Couplers

w Filters – Cavity Filters, Microstrip, Dielectric

Coax bendHorn Antenna

Wire Bonding

3D Antenna Pattern

Typical Modeled Devices

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What HFSS Gives You

w Rapid Virtual Prototyping w Arbitrary 3D Structuresw Multiple Ports/Multiple Modesw All microwave materials supported

w Calculatesw S, Y, Z parameters w SPICE Sub-Circuitsw Modes-to-Nodesw Differential Pairsw EigenModesw Electromagnetic fields

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DistributedModel

RLCG Matrix

TPAPCB/MCM SpiceLink

LumpedModel

S-Parameters& Fields

AnsoftLinks

SPICE Sub-Circuit

PSpice

PhysicalModel Serenade

HFSS Ensemble

Full-WaveSpice

Circuit/System

OptimetricsTM

optional

Quasi-Static Full-Wave

HSpice Maxwell Spice PN Spice

APDAllegroEncoreZuken

Series IVDesign Lab

Analog ArtistEDIF

Integration

How OptimetricsTM Falls Into The Ansoft Solution FlowIGES, STEP, GDSII,

ACIS, DXF

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What Is OptimetricsTM

“Optimization is a process of finding a better or more suitabledesign instance among the possible design variations”

w Optimetrics includes a Parametric and Optimization Analysis Modulew Compatible with all Ansoft 3D productsw Allows full Parametric and Optimization Analysis of models using multiple variables

w Think of it as being able to solve many model iterations at once rather than having to press the solve button many times

• Optimetrics provides an intuitive interface on top of the advanced macro language built into HFSS that lets you:

w Define model parameters which will varyw Setup a data table to specifically control iterations and/orw Identify performance specs to optimize

w Optimetrics also allows advanced users to tap directly into the powerful macro language for even greater customization

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What Can OptimetricsTM Do For Me

• Optimetrics functions as a design manager for HFSS...w Parameterize at all modeling stages

w Geometry (size, shape, orientation, quantity…)w Materials (lossless, complex, anisotropic…)w Boundaries (impedance/conductance boundaries, linked boundary scan angles,

symmetry or mode cases…)w Solution Setup

w Optimization can be performed toward an extensive array of cost functions and goalsw Circuit Parametersw Antenna Patternsw Emissionsw Derived Field Quantitiesw ...if you can post-process it, it can be used as a cost function!!

• …that allows for centralized control of design iterations in one common interface.

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Ansoft OptimetricsTM: Executive Commands Interface

Setup HFSS Project(geometry, materials, boundaries)

HFSS Project Solution Setup

Identify Output Results of Interest(S-parameters, field calculations, etc.)

Edit/Create Optimization Variables(e.g. create Cost functions from Output Results)

Setup Parametric/Optimization/Sensitivity Analysis

Run Parametrics/Optimetrics

Review/Plot Optimization Results

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Ansoft OptimetricsTM: Nominal Project

w Takes you directly to HFSSw Create a model as you normally would

or input existing modelw All actions are automatically recordedw Appropriate options for Driven and

Eigenmode Solution

w Material or boundary values to be varied entered via HFSS “Function” interface

w On-board editor for geometric variable creation

w Regardless of the number of variables to be parameterized, you only have to create the input model ONCE.

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Ansoft OptimetricsTM: Setup Solution Options

w Links directly to nominal problem’s solution setup

w Defines how the “Solution Setup” for each models iteration during the parametric or optimization analysis process shall be solved

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Ansoft OptimetricsTM: Setup Output Parameters

w Links to nominal project’s HFSS post-processors

w Use to define the output results from each model setup you are interested in comparing

w Circuit parameters directly obtainable

w Field parameters obtained by recording your post-processing steps as a macro

w Existing macros can simply be copied for frequently-used criteria

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Filter Cost Function: Norm TypesFilter Cost Function: Norm Types

w In case if one selects “L1 Norm”, is readily providing the value associated with this sub-goal.

w For “Euclidean Norm Squared” is assigned to the sub-goal.

w And finally, if “Maximum Norm” is selected, the associated value is simply defined by .

∫high

low

f

f

ferr )(

∫high

low

f

f

ferr )(2

{ })(,

max ferr

higflowff

∈

<−

=otherwise

rqfqfrferr

0)()(

)(Above

Close

Below

)()()( frfqferr −=

>−

=otherwise

rqfrfqferr

0)()(

)(

Definition for err(f)Relation

w The relation between the quantity and the reference curve defines a frequency dependent error function err(f).

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Ansoft OptimetricsTM: Edit Functions

w Automatically includes all variables/functions defined during nominal project setup and output parameters setup.

w Use to define functional relationships between input model variables

w e.g. aspect ratios

w Use to define additional functions (including cost functions) related to output parameters

w e.g. transmitted or reflected power w.r.t. S-parameter results

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Ansoft OptimetricsTM: Setup Analysis

w Access either parametric analysis or optimization analysis dialogs

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Ansoft OptimetricsTM: Parametric Setup

w Identify parametric setupsw Add variables (defined during

nominal setup) to tablew Setup variable sweep ranges

and number of stepsw Create table of parametric

combinations

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Ansoft OptimetricsTM: Optimization Setup

w Identify optimization parameters and ranges

w Select variables from those created in nominal problem and function lists

w Define range and step size of allowable values for each variable

w If desired, apply constraints between related variables.

w Define cost function and acceptable cost as optimization goal

w Define allowable number of Iterations

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Optimizers: Quasi Newton & Pattern SearchOptimizers: Quasi Newton & Pattern Search

w Quasi Newtonw The Quasi-Newton search is a “downhill” search, just like the steepest descent method. The difference

between the steepest descent method and this algorithm is that Quasi Newton utilizes some approximate second order derivatives when finding promising search directions. This is done in order to avoid the slow convergence rate of the steepest descent search due to zigzag search path. It initiates the search from a point in the design space, and iteratively tries to find better design points.

w Pattern Searchw This pattern is defined on a grid, and the grid is refined or coarsened according to the success rate of the

search. Like the quasi-Newton algorithm, this search is also iterative. First the pattern is evaluated (meaning that the cost function is calculated for each pattern point). Then decision is made about the next move. In case there is a better solution in the pattern, this is set to be the next iterate. If no better solution is found, then the grid is refined, and the algorithm starts over, hoping that ultimately there will be a better point found next time.

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Minimum Step & Maximum Step Variable ControlMinimum Step & Maximum Step Variable Control

w Maximum Step settings for Quasi Newton:w This parameter limits the “radius” of the line search. One should define Maximum Step for all the optimization

variables. These parameters define an ellipsoid around the origin of coordinate system of the design space. Accordingly, a search step along the search direction is greater than the maximum in that direction if, the step-vector’s end point is outside the ellipsoid. In case the line search predicts a step greater than the maximum allowed step in the search direction, the step is truncated, and the line search exited whatever is appropriate.

w Minimum Step settings for Quasi Newton:w This set of optimization parameters defines an ellipsoid similar to the above described one. When the step in

the search gets less than the minimum required in the given search direction, the search algorithm is stopped. So, this is really a stopping criteria for the search.

w Maximum Step settings for Pattern searchw In a previous section we have discussed the Pattern search algorithm. As described, the algorithm uses a

regular grid. The initial spacing of the grid is defined by Maximum Step parameters for each optimization variable.

w Minimum Step settings for Pattern searchw As in the case of the quasi-Newton search, this parameter triggers stopping of the search. The Pattern

search algorithm naturally refines the grid as the iterate closes to the optimum. When the grid gets refined so that the grid spacing becomes smaller than the Minimum Step settings, the algorithm stops searching any further.

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Ansoft OptimetricsTM: Add/Remove Output Columns

w Add columns for any entry in the function List

w Tabular contents are updated automatically as each setup is completed

w Table columns can be edited before or after solutions are complete

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Ansoft OptimetricsTM: Run… Analysis

w Run begins solutionw “Parametrics...” runs only parametric setups in table

w No optimization variables need be definedw “Optimization...” runs parametric steps (if present)

and optimization enginew Parametric setups aid in slope definition for

optimization stepsw “Recompute Output Parameters” will re-derive

outputs if requested parameters change after setups are run

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Air-filled Box

Substrate

Microstrip Filter

Symmetry Plane

Port 1

Port 2

Example 1: Parametric StudyMicrostrip lowpass filter

S21 data automaticallyextracted to study how changes in permittivityaffect filter response

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w Design variablesw Radius d1 of Via 1w Radius d2 of Via 2w Length l1 of Resonator 1w Length l2 of Resonator 2

Example 2: OptimetricsTM

Microstrip bandpass filter

l1 l1l2

d1

d1d2 d2

w

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Example 3: OptimetricsTM

PIFA: Capacitive load width (Wcap) vs. plate separation (dcap)

hpifa

x

lcf

lpifa

dcf

Wcap

dcap

Design Curve IVWcap = 0.3mm dcap = 3.0mm

Increasing Load Capacitance

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Example 4: OptimetricsTM

Master/Slave scan angle control

Port1

Master

Slave

Port1 Port2

Port3Port4

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Example 5: OptimetricsTM

Sensitivity analysis

Goalsw Characterize Design Point: Slope, Curvaturew Interpolate Response for Specific Tolerance Value

tol tol tol tol

Worst Case

Best Case

Design 1 Design 2

Design Variable

Cos

t

Design Variable

Cos

t

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Optimetrics ExampleOptimetrics Example

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CP Patch Antenna CP Patch Antenna -- OptimetricsOptimetrics

Patch AntennaThis patch antenna example is intended to show, using Ansoft’s Optimetrics with HFSS, how to create, simulate, and optimize the right-hand circular polarization (RHCP) response of a patch antenna in the 2.4 GHz ISM band (Bluetooth, 802.11b, etc.).

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Patch Antenna: Getting StartedPatch Antenna: Getting Started

w Ansoft Design Environmentw The following features of the Ansoft Optimetrics Design Environment are used to create this passive device model

w Analysis: Optimizationw Parametric geometryw User defined project variablesw Database export

w The following features of the Ansoft HFSS Design Environment are used to create this passive device model

w 3D Solid Modelingw Primitives: box, rectangle, cylinder, circlew Boolean: subtract, duplicate around axis

w Materialsw Create user defined material

w Boundary/Sourcesw Ports: Lumped gap port

w Fields Post-Processingw Compute radiated far-fields

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Select the menu item Lines/RectangleFirst point: X= -45.0, Y= -45.0Size: X= 90.0, Y= 90.0Name: groundplaneSelect the menu item View/Fit All/All Views

Launching Ansoft OptimetricsStart the Maxwell Control PanelClick Project.

Create and open a New Ansoft Optimetrics 2 Project named: opt_patch_antenna

Creating the Nominal ProjectFrom the Optimetrics Executive Commands, click the Nominal Project button and select Create.

The nominal project dialog will appear. Enter the Nominal Project Name: nom_patch_antennaSelect Product: Ansoft High Frequency Structure Simulator 8Click OK.

Click the Draw button and the 3D Solid Modeler window will appear. If prompted to set the units, choose: mm orSelect the menu item: Options/Units

Select the Units of: mm

Select the menu item Solids/BoxBox base vertex: X= -22.5, Y= -22.5, Z= 0.0Size: X= 45.0, Y= 45.0, Z= 5.0Name: substrate

Patch Antenna: Getting Started

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Select the menu item Lines/RectangleFirst point: X = -16.0, Y = -16.0, Z = 5.0Size: X = 32.0, Y= 32.0Name: patch

Patch Antenna: Solid Model Construction

Select the menu item Solids/CylinderBase center: X= 0.0, Y= 8.0, Z= 0.0Cylinder axis: zR: 0.5, H: 5.0Num segments: 12Name: feed

Select the menu item Solids/BoxBox base vertex: X= -80.0, Y= -80.0, Z= -35.0Size: X= 160.0, Y= 160.0, Z= 75Name: airSelect the menu item View/Fit All/All Views

The basic geometry is now complete. But we have a few more things to do in the Draw module.

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Create a hole in the “groundplane” for the port.Edit/Select: select the object “port”Edit/Copy then Edit/PasteSolids/Subtract

Select “groundplane”. Click OKSelect “port1”. Click OK

Patch Antenna: Solid Model ConstructionPatch Antenna: Solid Model Construction

Create a hole in the port to accommodate the feed.Edit/Select: select the object “feed”Edit/Copy then Edit/PasteSolids/Subtract

Select “port”. Click OKSelect “feed1”. Click OK

Select the menu item Lines/CircleCircle center: X = 0.0, Y = 8.0, Z = 0.0Circle axis: zR: 1.5Num segments: 12Name: port

Next create the port. This will be a 1mm wide annular ring around the base of the “feed”. Later this will be defined as a 50 ohm, lumped gap port. Consider it a virtual, 50 ohm coax feed.

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Patch Antenna: Solid Model ConstructionPatch Antenna: Solid Model Construction

For a RHCP response, chamfer opposing corners of the “patch”. This is done by creating triangles of the appropriate size and location and subtracting them from the “patch”.

Select the menu item Lines/Polyline.Edit/create: “chamCut1”First point: X = 0.0, Y = 0.0, Z= 0.0Second point: X = 6.0, Y = 0.0, Z= 0.0Third point: X = 0.0, Y = 6.0, Z= 0.0Click Close. Click Done.

Move the object “chamCut1” to the corner of “patch”.Edit/Select: select object “chamCut1”. Click OK.Arrange/Move

Enter vector: X = -16.0, Y = -16.0, Z = 5.0Click Enter.

Copy “chamCut”1 into the opposing corner.Edit/Select: select object “chamCut1”. Click OKEdit/Duplicate/Around Axis

Axis: zAngle: 180Total number: 2Click Enter.

Subtract “chamCut1” and “chamCut2” from “patch”Solids/Subtract

Select “patch”. Click OK.Multiple select “chamCut1” and “chamCut2”. Click OK.

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Patch Antenna: Editing MacroPatch Antenna: Editing Macro

Now edit the command history. This is an automatically recorded modeler macro that has the same name as the HFSS project, “nom_patch_antenna.mac”, and is the macro that Optimetrics will use. Here variables will be assigned to parameters of the 3D model.

Select the menu item Edit/Command History.

Shown in the Ansoft Macro Editoris the process of assigning variables to the parameters for the rectangle “groundplane”. The following variables will be assigned:

Independent variables for Optimetrics: PatchSize, ChamSizeOther independent variables: SubHeight, GplaneSize, SubSize, FeedLocationDependent variable: gplaneStart, patchStart, subStart.

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Patch Antenna: Editing Macro, Variable Patch Antenna: Editing Macro, Variable AssignmentAssignment

groundplane: Highlight the line: Rectangle [-45, -45, 0] 2 90 90 "groundplane" 1. Enter the following variable names in the right-hand fields:

Starting point: X = gplaneStart, Y = gplaneStart, Z = 0.0Size: X = GplaneSize, Y = GplaneSizeClick Accept.Click Yes twice when prompted.(*Note that the lines have been re-numbered)

substrate: Highlight the line: Box [-22.5, -22.5, 0] 45 45 5 "substrate". Enter the following variable names in the right-hand fields:

Base vertex: X = subStart, Y = subStart, Z = 0.0Size: X = SubSize, Y = SubSize, Z = SubHeightClick Accept.Click Yes thrice when prompted.

patch: Highlight the line: Rectangle [-16, -16, 5] 2 32 32 "patch" 1. Enter the following variable names in the right-hand fields:

Starting point: X = patchStart, Y = patchStart, Z = SubHeightSize: X = PatchSize, Y = PatchSizeClick Accept.Click Yes twice when prompted.

*Note: The lines are re-numbered whenever a new variable or function is defined. These lines are added at the beginning of the macro and are not visible in the Assign parameter mode. To view the additional lines, select the menu item View/Edit mode. Select menu items View/Assign parameter mode to leave this view. See appendix for a copy of the full Command History macro with variable assignments.

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Patch Antenna: Editing Macro, Variable Patch Antenna: Editing Macro, Variable Assignment, cont.Assignment, cont.

feed: Highlight the line: Cyl [0, 8, 0] 2 0.5 5 "feed" 12 [0.5, 8, 5]. Enter the following variable names in the right-hand fields:

Center point of cylinder base: X = 0.0, Y = FeedLocation, Z = 0.0Height: SubHeightClick Accept.Click Yes when prompted.

port: Highlight the line: Circle [0, 8, 0] 2 1.5 "port" 1 12 [1.5, 8, 0]. Enter the following variable names in the right-hand fields:

Center point: X = 0, Y = FeedLocation, Z = 0.0Click Accept.

chamCut1: Highlight the line: AddVert [6, 0, 0]. Enter the following variable names in the right-hand fields:Vertex: X = ChamSize, Y = 0.0, Z = 0.0Click Accept.Click Yes when prompted.

chamCut1: Highlight the line: AddVert [0, 6, 0]. Enter the following variable names in the right-hand fields:Vertex: X = 0.0, Y = ChamSize, Z = 0.0Click Accept.

Move chamCut1: Highlight the line: Move <-16, -16, 5>. Enter the following variable names in the right-hand fields:

Vector: X = patchStart, Y = patchStart, Z = SubHeightClick Accept.

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Patch Antenna: Editing Macro, Edit ParametersPatch Antenna: Editing Macro, Edit Parameters

From the Ansoft Macro Editor go to Edit/All Parameters.Here we assign the relationship between the independent and dependent variables.

Change the expressions for the three dependent variables, gplaneStart, patchStart, subStart. This is done by highlighting the variable and then entering the appropriate expression in the Expression field. Click Update after entering the expression.

Note that the independent variables start with upper case letters and the dependent with lower case. Following this convention will make the independent variables show up at the top of this list.

The other independent variables are there in case we want to make additional variation to the model. e.g. How does the peak gain change as a function of the substrate height (SubHeight).

Click Done. In the Macro Editor select the menu item File/Apply changes. Exit the Macro Editor and then exit the Draw module. Click Yes when prompted to save changes.

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Patch Antenna: Material Manager

Assigning Material PropertiesFrom the Executive Commands, click the Setup Materialsbutton and the Material Manager window will appear.

Assign the materials as shown.

Note we have created a local material definition, “Rogers4003”To assign a local material, under the Material pull down select, Add.Type Rogers4003 in the name window.Assign the Rel. Permittivity and Elec. Loss Tan as shown.Click Enter.

Click Exit. Click Yes when prompted to save.

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Patch Antenna: Boundary/SourcesPatch Antenna: Boundary/Sources

Creating Boundaries/SourcesFrom the Executive Commands, click the Setup Boundary/Sources button and the Boundary/Source Managerwindow will appear.

BoundariesVerify that there are no face/boundary selections

Select the menu item Edit/Deselect All if it is not grayed out.

Select the menu item Edit/Select/By Name.Selection Type: FaceFaces: Using the control key, multiple select the faces of “groundplane” (Face27) and ”patch” (Face29).Click Done.Choose Boundary.Select Finite conductivity.Accept default value for conductivity.Name: conductorsClick Assign.

Select the menu item Edit/Select/By NameSelection Type: FaceFaces: Select all the faces of “air” (Face21-26).Click Done.Choose Boundary.Select Radiation.Name: radBoundaryClick Assign.

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Patch Antenna: Boundary/Sources, cont.Patch Antenna: Boundary/Sources, cont.

SourceSelect the menu item Edit/Select/By Name

Selection Type: FaceObjects: portFaces: Select the face of the port (Face28)Click Done.Choose Source.Select Port.Name: port1Type: Lumped Gap Port

Resistance: 50 ohmsReactance: 0 ohms

Check the Use Impedance Line and Use Calibration Line boxes.Under the impedance line Edit Line pull down select Set.

Impedance Start: X = 0.0, Y= 9.5, Z = 0.0Vector: X = 0, Y = -1.0, Z = 0

Under the calibration line Edit Line pull down select Copy Impedance.Select View Modes.Number of Modes: 1Click Assign.

Select the menu item File/Exit and click Yes when prompted to save.

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Patch Antenna: Setup SolutionPatch Antenna: Setup Solution

Setting Up the SolutionFrom the Executive Commands window, click the Setup Solution button and the Setup Solution dialog will appear.

Check both Single Frequency andAdaptive.

Single Frequency : 2.45 GHzRequested Passes : 10Tet. Refinement : 20Max Delta S : 0.001

From the Starting Mesh listSelect Initial.

For SolveChoose All, for a full 3D solution.

Click OK to accept the changes to the HFSS Solution Setup.

Performing the SolutionFrom the Executive Commands window, click Solve.

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Patch Antenna: 3D PostPatch Antenna: 3D Post--Process and Macro Process and Macro CreationCreationFields Post-Process and Macro Creation

From the Executive Commands, click the Post Process button and select Fields.

Select the menu item File/Macro/Start Recording.From the Input Macro Name file browser, select the default (postfld3.mac) by clicking the OK button.Select the menu item Radiation/Compute/Far Field.

In the Compute Far Field window accept the defaults and click OK.In the Plot Far Field window accept the defaults and click OK.Select the menu item File/Macro/Stop Recording. Click OK.

Select the menu item File/Macro/Edit Macro.Select the menu item View/Edit Mode.

Delete the last 13 lines of the macro (every line after “ComputeFarField”)Select the menu item Edit/Database Export Macro/Add.

In database cell (1,1) type AxialRatio.Click the . . . button next to database cell (1,2).

Select Value of field at the specific location. Click OKClick the Far Field button. Select Axial Ratio under the Quantity pulldown. Click OK. Click OK.

In the Ansoft Macro Editor Select the menu item File/Save. Exit the Macro Editor.

In the 3D Post-Processor select the menu items File/Macro Execute. Select the “postfld3.mac” macro. Click OK.

Exit the 3D Post-Processor.

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Patch Antenna: Wait! What just happened!Patch Antenna: Wait! What just happened!

Creation of the 3D Post-Processor Macro.Since our ultimate goal is to optimize the RHCP of the patch antenna we had to somehow send this information to Optimetrics. To let Optimetrics know how good the RHCP was, we elected to calculate the axial ratio of the radiation pattern directly above the patch antenna, phi = 0, theta = 0. The axial ratio represents how circular the polarization is with the ideal value being 1.

To calculate the axial ratio we needed the far field data. Thus the first step was to record a macro, called “postfld3.mac”, that executed the steps to calculate the far field data at the point of interest, phi = 0, theta = 0.

That macro included steps that we do not need. Mainly the commands associated with creating the 2D far field plots. Thus the last 13 lines in the macro were deleted.

Now that we had the far field data, we added a Database Export Macro that wrote the value of the axial ratio out to a file called “postfld3.udb”. Later on we will tell Optimetrics to look into this file to extract the value of the axial ratio for the patch antenna.

Note: It was not necessary to known the Ansoft Macro Language. The steps associated with writing the macro commands were automated. Of coarse it will not always be the case that every macro you wish to write can be written via automation. In these cases refer to the manual “Introduction to the Ansoft Macro Language”.

See the appendix for a copy of the Fields Post-Processor macro just created.

Now lets go back to the HFSS project.

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Patch Antenna:Patch Antenna:

Exit HFSSFrom the Executive Commands window, click Setup Solutions.

In the HFSS Setup Solution panel enter 10 into requested adaptive passes and select initial for the starting mesh. Click OK.

From the Executive Commands window, click Exit to return to Optimetrics.

Setting Up the Output ParameterFrom the Optimetrics Executive Commandswindow, click Setup Output Parameters and select Create Standard Outputs

Solution Type: Single FrequencyData Type: S MatrixType S11mag in the Parameter Name field. Click Add Circuit Parameter. Click OK.

This parameter assignment will let us monitor S11 at the solution frequency, 2.45 GHz.

From the Executive Commands window, click Setup Output Parameters and select Select Macros.

Select 3D Fields Post Processor from the Module pulldown. Highlight “postfld3d.mac” under “Available Macros”. Click Add->. Click OK.

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Patch Antenna: Edit FunctionsPatch Antenna: Edit Functions

Edit FunctionsFrom the Executive Commands window, click Edit Functions.

Using the Project Parameters dialog:Add a new variable: costValue: 10*log(AxialRatio). Click Add

Note: Defining the cost function in dBs means our cost function value will be zero (10*log(1)) at optimum.Click Done to return to the Executive Commands window.

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Patch Antenna: Setup Analysis, ParametricsPatch Antenna: Setup Analysis, Parametrics

Setting Up the Parametric SweepFrom the Executive Commands window, click Setup Analysis and select Parametrics.

In the Setup Variables “opt_patch_antenna” windowSelect menu item : Variables/Add.

Using the control key, multiple select the variables ChamSize and PatchSize. Click OK.

Select the menu item Data/Sweep.Highlight the variable ChamSize.

t_start: 5t_end: 7#samples: 3Click Accept.

Highlight the variable PatchSize.t_start: 31t_end: 33#samples: 3Click Accept. Click OK.

Select the menu item File/Exit. Click Yes when prompted to save changes.

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Patch Antenna: Setup Analysis, OptimetricsPatch Antenna: Setup Analysis, Optimetrics

Setting Up the Optimetrics AnalysisFrom the Executive Commands window, click Setup Analysis and select Optimization.

Using the Setup Optimization dialogOptimizer : Pattern Search OptimizerCost Function : costClick the Design Variables: Add button

Select Variable: ChamSizeMinimum: 4Maximum: 8Min. Step: 0Max. Step: 1Click OK

Click the Design Variables: Add buttonSelect Variable: PatchSizeMinimum: 30Maximum: 35Min. Step: 0Max. Step: 1Click OK

Acceptable Cost: 0Max Iterations: 100Save Fields: NoClick OK.

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Patch Antenna: Add Output ColumnsPatch Antenna: Add Output Columns

Add/Remove Output ColumnsFrom the Executive Commands window, click Add/Remove Output Columns.

Using the Add/Remove Output Columns dialog:Using the control key, multiple select all of the Available Entries, AxialRatio, S11mag, cost.Click Add-> to move the Available Entries to the Table Entries.Click OK.

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Patch Antenna: RunPatch Antenna: Run

Performing the SolutionIn the Executive Commands window, under the Run pulldown, select Optimization Analysis to start the solution.

Monitoring the SolutionThe first nine runs will consist of the parametric setup from earlier. This will give Optimetrics a global view of the cost function. After the parametric sweep is finished, Optimetrics begins to vary the design variables, “ChamSize” and “PatchSize” to reduce the cost function.

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Patch Antenna: RunPatch Antenna: Run

Monitoring the Solution, cont.After 46 Setups, Optimetrics finds values for “ChamSize” (5.32617) and “PatchSize” (30.375) that achieve a cost function value of 0.00397905 corresponding to an axial ratio of 1.00095. The run was aborted after 48 runs.

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ANSOFT CORPORATIONCorporate HeadquartersFour Station SquarePittsburgh, PA 15219-1119Tel: 412-261-3200Fax: 412-471-9427Internet: info@ansoft.comwww.ansoft.com

Lawrence Unterberger(lunterberger@ansoft.com)

805.581.0823

Matt Commens(mcommens@ansoft.com)

847.925.9066