Presentation - An Introduction to HFSS Optimetrics

1 

Welcome to the 

2002 Ansoft HFSS/Ensemble 

Users’ Workshop

2 

An Introduction To HFSS Optimetrics TM 

Lawrence Unterberger 

Matt Commens 

HF Applications Engineers 

Ansoft Corporation 

Optimetrics TM can take 

control of your model to 

achieve performance 

improvements over initial 

designs

3 

Agenda 

◗ HFSS Overview 

◗ What is Optimetrics TM 

◗ Optimetrics Flow 

◗ Example Results 

◗ Optimization of a Patch Antenna 

◗ Conclusion

4 

What Is HFSS 

◗ 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. 

Via hole 

With Solder 

Microstrip 

Meander line 

Leadframe 

Uniform 

Transmission 

lines

5 

Typical Modeled Devices 

◗ Package Modeling – BGA, QFP, Flip-Chip 

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

◗ Silicon/GaSa - Spiral Inductors, Transformers 

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

◗ 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) 

◗ Connectors – Coax, Transitions 

◗ Waveguide – Filters, Resonators, Transitions, Couplers 

◗ Filters – Cavity Filters, Microstrip, Dielectric 

Horn Antenna 

Coax bend 

3D Antenna Pattern 

Wire Bonding

6 

What HFSS Gives You 

◗ Rapid Virtual Prototyping 

◗ Arbitrary 3D Structures 

◗ Multiple Ports/Multiple Modes 

◗ All microwave materials supported 

◗ Calculates 

◗ S, Y, Z parameters 

◗ SPICE Sub-Circuits 

◗ Modes-to-Nodes 

◗ Differential Pairs 

◗ EigenModes 

◗ Electromagnetic fields

7 

How Optimetrics TM Falls Into The Ansoft Solution Flow 

APD 

Allegro 

Encore 

Zuken 

TPA 

PCB/MCM 

S-Parameters 

Quasi-Static RLCG Matrix 

Full-Wave 

& Fields 

Distributed 

Model 

Integration 

AnsoftLinks 

PSpice 

SpiceLink 

Lumped 

Model 

IGES, STEP, GDSII, 

ACIS, DXF 

Physical 

Model 

Optimetrics TM 

optional 

SPICE Sub-Circuit 

Circuit/System 

Serenade 

HFSS Ensemble 

Full-Wave 

Spice 

HSpice Maxwell Spice PN Spice 

Series IV 

Design Lab 

Analog Artist 

EDIF

8 

What Is Optimetrics TM 

“Optimization is a process of finding a better or more suitable 

design instance among the possible design variations” 

◗ Optimetrics includes a Parametric and Optimization Analysis Module 

◗ Compatible with all Ansoft 3D products 

◗ Allows full Parametric and Optimization Analysis of models using multiple variables 

◗ 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: 

◗ Define model parameters which will vary 

◗ Setup a data table to specifically control iterations and/or 

◗ Identify performance specs to optimize 

◗ Optimetrics also allows advanced users to tap directly into the powerful macro 

language for even greater customization

9 

What Can Optimetrics TM Do For Me 

• Optimetrics functions as a design manager for HFSS... 

◗ Parameterize at all modeling stages 

◗ Geometry (size, shape, orientation, quantity…) 

◗ Materials (lossless, complex, anisotropic…) 

◗ Boundaries (impedance/conductance boundaries, linked boundary scan angles, 

symmetry or mode cases…) 

◗ Solution Setup 

◗ Optimization can be performed toward an extensive array of cost functions and goals 

◗ Circuit Parameters 

◗ Antenna Patterns 

◗ Emissions 

◗ Derived Field Quantities 

◗ ...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.

10 

Ansoft Optimetrics TM : 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

11 

Ansoft Optimetrics TM : Nominal Project 

◗ Takes you directly to HFSS 

◗ Create a model as you normally would 

or input existing model 

◗ All actions are automatically recorded 

◗ Appropriate options for Driven and 

Eigenmode Solution 

◗ Material or boundary values to be 

varied entered via HFSS “Function” 

interface 

◗ On-board editor for geometric variable 

creation 

◗ Regardless of the number of variables to be 

parameterized, you only have to create the 

input model ONCE.

12 

Ansoft Optimetrics TM : Setup Solution Options 

◗ Links directly to nominal problem’s 

solution setup 

◗ Defines how the “Solution Setup” for 

each models iteration during the 

parametric or optimization analysis 

process shall be solved

13 

Ansoft Optimetrics TM : Setup Output Parameters 

◗ Links to nominal project’s HFSS postprocessors 

◗ Use to define the output results from 

each model setup you are interested in 

comparing 

◗ Circuit parameters directly 

obtainable 

◗ Field parameters obtained by 

recording your post-processing 

steps as a macro 

◗ Existing macros can simply be 

copied for frequently-used 

criteria

14 

Filter Cost Function: Norm Types 

◗ The relation between the quantity and the reference curve defines a frequency dependent error 

function err(f). 

Relation 

Below 

Close 

Above 

◗ In case if one selects “L1 Norm”, err ( f ) is readily providing the value associated with this sub-goal. 

f 

high 

∫ 

2 

◗ For “Euclidean Norm Squared” err ( f ) is assigned to the sub-goal. 

f 

low 

f 

f 

high 

∫ 

low 

Definition for err(f) 

⎧ q( 

f ) − r( 

f ) q > r 

err( 

f ) = ⎨ 

⎩ 0 otherwise 

err( f ) = q( 

f ) − r( 

f ) 

⎧ r( 

f ) − q( 

f ) q < r 

err( 

f ) = ⎨ 

⎩ 0 otherwise 

max f 

f∈⎡ 

f 

low 

, f ⎤ 

⎢⎣ hig⎥⎦ 

◗ And finally, if “Maximum Norm” is selected, the associated value is simply defined by { err( 

) } .

15 

Ansoft Optimetrics TM : Edit Functions 

◗ Automatically includes all 

variables/functions defined during 

nominal project setup and output 

parameters setup. 

◗ Use to define functional 

relationships between input model 

variables 

◗ e.g. aspect ratios 

◗ Use to define additional functions 

(including cost functions) related to 

output parameters 

◗ e.g. transmitted or reflected power 

w.r.t. S-parameter results

16 

Ansoft Optimetrics TM : Setup Analysis 

◗ Access either parametric analysis or 

optimization analysis dialogs

17 

Ansoft Optimetrics TM : Parametric Setup 

◗ Identify parametric setups 

◗ Add variables (defined during 

nominal setup) to table 

◗ Setup variable sweep ranges 

and number of steps 

◗ Create table of parametric 

combinations

18 

Ansoft Optimetrics TM : Optimization Setup 

◗ Identify optimization parameters and 

ranges 

◗ Select variables from those 

created in nominal problem 

and function lists 

◗ Define range and step size of 

allowable values for each 

variable 

◗ If desired, apply constraints 

between related variables. 

◗ Define cost function and 

acceptable cost as optimization 

goal 

◗ Define allowable number of 

Iterations

19 

Optimizers: Quasi Newton & Pattern Search 

◗ Quasi Newton 

◗ 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. 

◗ Pattern Search 

◗ 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.

20 

Minimum Step & Maximum Step Variable Control 

◗ Maximum Step settings for Quasi Newton: 

◗ 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. 

◗ Minimum Step settings for Quasi Newton: 

◗ 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. 

◗ Maximum Step settings for Pattern search 

◗ 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. 

◗ Minimum Step settings for Pattern search 

◗ 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.

21 

Ansoft Optimetrics TM : Add/Remove Output Columns 

◗ Add columns for any entry in the 

function List 

◗ Tabular contents are updated 

automatically as each setup is 

completed 

◗ Table columns can be edited 

before or after solutions are 

complete

22 

Ansoft Optimetrics TM : Run… Analysis 

◗ Run begins solution 

◗ “Parametrics...” runs only parametric setups in table 

◗ No optimization variables need be defined 

◗ “Optimization...” runs parametric steps (if present) 

and optimization engine 

◗ Parametric setups aid in slope definition for 

optimization steps 

◗ “Recompute Output Parameters” will re-derive 

outputs if requested parameters change after setups 

are run

23 

Example 1: Parametric Study 

Microstrip lowpass filter 

Substrate 

Air-filled Box 

Port 1 

Microstrip 

Filter 

Port 2 

Symmetry 

Plane 

S21 data automatically 

extracted to study how 

changes in permittivity 

affect filter response

24 

Example 2: Optimetrics TM 

Microstrip bandpass filter 

◗ Design variables 

◗ Radius d1 of Via 1 

◗ Radius d2 of Via 2 

◗ Length l1 of Resonator 1 

◗ Length l2 of Resonator 2 

w 

d 

1 

l1 l2 l1 

d2 d2 

d 

1

25 


PIFA: Capacitive load width (W cap ) vs. plate separation (d cap ) 

h pifa 

x 

l cf 

l pifa 

d cf 

W cap 

d cap 

Increasing Load 

Capacitance 

Design Curve IV 

W cap= 0.3mm 

d cap = 3.0mm

Port4 

Port1 

26 


Master/Slave scan angle control 

Port1 

Port3 

Port2 

Master 

Slave

27 


Sensitivity analysis 

Cost 

Goals 

Design 1 Design 2 

Worst 

Case 

tol tol Best 

tol tol 

Design Variable 

Case 

Cost 

◗ Characterize Design Point: Slope, Curvature 

◗ Interpolate Response for Specific Tolerance Value 

Design Variable

28 

Optimetrics Example

29 

CP Patch Antenna - Optimetrics 

Patch Antenna 

This 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.).

30 

Patch Antenna: Getting Started 

◗ Ansoft Design Environment 

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

◗ Analysis: Optimization 

◗ Parametric geometry 

◗ User defined project variables 

◗ Database export 

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

◗ 3D Solid Modeling 

◗ Primitives: box, rectangle, cylinder, circle 

◗ Boolean: subtract, duplicate around axis 

◗ Materials 

◗ Create user defined material 

◗ Boundary/Sources 

◗ Ports: Lumped gap port 

◗ Fields Post-Processing 

◗ Compute radiated far-fields

31 

Patch Antenna: Getting Started 

Launching Ansoft Optimetrics 

Start the Maxwell Control Panel 

Click Project. 

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

Creating the Nominal Project 

From 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_antenna 

Select Product: Ansoft High Frequency Structure Simulator 8 

Click OK. 

Click the Draw button and the 3D Solid Modeler window will appear. If prompted to set the units, choose: mm or 

Select the menu item: Options/Units 

Select the Units of: mm 

Select the menu item Lines/Rectangle 

First point: X= -45.0, Y= -45.0 

Size: X= 90.0, Y= 90.0 

Name: groundplane 

Select the menu item View/Fit All/All Views 

Select the menu item Solids/Box 

Box base vertex: X= -22.5, Y= -22.5, Z= 0.0 

Size: X= 45.0, Y= 45.0, Z= 5.0 

Name: substrate

32 

Patch Antenna: Solid Model Construction 

Select the menu item Lines/Rectangle 

First point: X = -16.0, Y = -16.0, Z = 5.0 

Size: X = 32.0, Y= 32.0 

Name: patch 

Select the menu item Solids/Cylinder 

Base center: X= 0.0, Y= 8.0, Z= 0.0 

Cylinder axis: z 

R: 0.5, H: 5.0 

Num segments: 12 

Name: feed 

Select the menu item Solids/Box 

Box base vertex: X= -80.0, Y= -80.0, Z= -35.0 

Size: X= 160.0, Y= 160.0, Z= 75 

Name: air 

Select 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.

33 


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. 

Select the menu item Lines/Circle 

Circle center: X = 0.0, Y = 8.0, Z = 0.0 

Circle axis: z 

R: 1.5 

Num segments: 12 

Name: port 

Create a hole in the “groundplane” for the port. 

Edit/Select: select the object “port” 

Edit/Copy then Edit/Paste 

Solids/Subtract 

Select “groundplane”. Click OK 

Select “port1”. Click OK 

Create a hole in the port to accommodate the feed. 

Edit/Select: select the object “feed” 

Edit/Copy then Edit/Paste 


Select “port”. Click OK 

Select “feed1”. Click OK

34 


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= 0.0 

Second point: X = 6.0, Y = 0.0, Z= 0.0 

Third point: X = 0.0, Y = 6.0, Z= 0.0 

Click 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 = 5.0 

Click Enter. 

Copy “chamCut”1 into the opposing corner. 

Edit/Select: select object “chamCut1”. Click OK 

Edit/Duplicate/Around Axis 

Axis: z 

Angle: 180 

Total number: 2 

Click Enter. 

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


Select “patch”. Click OK. 

Multiple select “chamCut1” and “chamCut2”. 

Click OK.

35 

Patch 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 Editor 

is the process of assigning 

variables to the parameters for the 

rectangle “groundplane”. The 

following variables will be assigned: 

Independent variables for 

Optimetrics: PatchSize, 

ChamSize 

Other independent 

variables: SubHeight, 

GplaneSize, SubSize, 

FeedLocation 

Dependent variable: 

gplaneStart, patchStart, 

subStart.

36 

Patch Antenna: Editing Macro, Variable 

Assignment 

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 = 0.0 

Size: X = GplaneSize, Y = GplaneSize 

Click 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 = 0.0 

Size: X = SubSize, Y = SubSize, Z = SubHeight 

Click 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 righthand 

fields: 

Starting point: X = patchStart, Y = patchStart, Z = SubHeight 

Size: X = PatchSize, Y = PatchSize 

Click 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.

37 

Patch Antenna: Editing Macro, Variable 

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 righthand 

fields: 

Center point of cylinder base: X = 0.0, Y = FeedLocation, Z = 0.0 

Height: SubHeight 

Click 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 = 0.0 

Click 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 = 0.0 

Click 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 = 0.0 

Click Accept. 

Move chamCut1: Highlight the line: Move . Enter the following variable names in the right-hand 

fields: 

Vector: X = patchStart, Y = patchStart, Z = SubHeight 

Click Accept.

38 

Patch 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.

39 

Patch Antenna: Material Manager 

Assigning Material Properties 

From the Executive Commands, click the Setup Materials 

button 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.

40 

Patch Antenna: Boundary/Sources 

Creating Boundaries/Sources 

From the Executive Commands, click the Setup Boundary/Sources button and the Boundary/Source Manager 

window will appear. 

Boundaries 

Verify 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: Face 

Faces: 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: conductors 

Click Assign. 

Select the menu item Edit/Select/By Name 


Faces: Select all the faces of “air” (Face21-26). 

Click Done. 

Choose Boundary. 

Select Radiation. 

Name: radBoundary 

Click Assign.

41 

Patch Antenna: Boundary/Sources, cont. 

Source 

Select the menu item Edit/Select/By Name 


Objects: port 

Faces: Select the face of the port (Face28) 

Click Done. 

Choose Source. 

Select Port. 

Name: port1 

Type: Lumped Gap Port 

Resistance: 50 ohms 

Reactance: 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 = 0.0 

Vector: X = 0, Y = -1.0, Z = 0 

Under the calibration line Edit Line pull down 

select Copy Impedance. 

Select View Modes. 

Number of Modes: 1 

Click Assign. 

Select the menu item File/Exit and click Yes when 

prompted to save.

42 

Patch Antenna: Setup Solution 

Setting Up the Solution 

From the Executive Commands window, 

click the Setup Solution button and the 

Setup Solution dialog will appear. 

Check both Single Frequency and 

Adaptive. 

Single Frequency : 2.45 GHz 

Requested Passes : 10 

Tet. Refinement : 20 

Max Delta S : 0.001 

From the Starting Mesh list 

Select Initial. 

For Solve 

Choose All, for a full 3D solution. 

Click OK to accept the changes to the 

HFSS Solution Setup. 

Performing the Solution 

From the Executive Commands window, 

click Solve.

43 

Patch Antenna: 3D Post-Process Post Process and Macro 

Creation 

Fields 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 OK 

Click 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.

44 

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.

45 

Patch Antenna: 

Exit HFSS 

From 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 Parameter 

From the Optimetrics Executive Commands 

window, click Setup Output Parameters and select 

Create Standard Outputs 

Solution Type: Single Frequency 

Data Type: S Matrix 

Type 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.

46 

Patch Antenna: Edit Functions 

Edit Functions 

From the Executive Commands window, click Edit Functions. 

Using the Project Parameters dialog: 

Add a new variable: cost 

Value: 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.

47 

Patch Antenna: Setup Analysis, Parametrics 

Setting Up the Parametric Sweep 

From the Executive Commands window, click Setup 

Analysis and select Parametrics. 

In the Setup Variables “opt_patch_antenna” window 

Select 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: 5 

t_end: 7 

#samples: 3 

Click Accept. 

Highlight the variable PatchSize. 

t_start: 31 

t_end: 33 

#samples: 3 

Click Accept. Click OK. 

Select the menu item File/Exit. Click Yes when 

prompted to save changes.

48 

Patch Antenna: Setup Analysis, Optimetrics 

Setting Up the Optimetrics Analysis 

From the Executive Commands window, click 

Setup Analysis and select Optimization. 

Using the Setup Optimization dialog 

Optimizer : Pattern Search Optimizer 

Cost Function : cost 

Click the Design Variables: Add button 

Select Variable: ChamSize 

Minimum: 4 

Maximum: 8 

Min. Step: 0 

Max. Step: 1 

Click OK 

Click the Design Variables: Add button 

Select Variable: PatchSize 

Minimum: 30 

Maximum: 35 

Min. Step: 0 

Max. Step: 1 

Click OK 

Acceptable Cost: 0 

Max Iterations: 100 

Save Fields: No 

Click OK.

49 

Patch Antenna: Add Output Columns 

Add/Remove Output Columns 

From 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.

50 

Patch Antenna: Run 

Performing the Solution 

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

Monitoring the Solution 

The 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.

51 

Patch 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.

52 

Lawrence Unterberger 

(lunterberger@ansoft.com) 

805.581.0823 

ANSOFT CORPORATION 

Corporate Headquarters 

Four Station Square 

Pittsburgh, PA 15219-1119 

Tel: 412-261-3200 

Fax: 412-471-9427 

Internet: info@ansoft.com 

www.ansoft.com 

Matt Commens 

(mcommens@ansoft.com) 

847.925.9066

Presentation - An Introduction to HFSS Optimetrics

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