Ansoft Corporation

Four Station Square, Suite 200

Pittsburgh, PA 15219-1119 USA

(412) 261-3200

Ansoft HFSS 3D Post Processor and

Calculator

Topics Covered General Functions

3D Post-Processor Interface Mesh Plotting Excitations

Driven Solutions Eigenmode Solutions

Field Plotting Quantities, Geometry, Settings, Animation Plot Management

Near/Far Field Processing Computing and Displaying Antenna and EMI

patterns

The Field Calculator Calculator Layout

Examples

HFSS 3D Post-Processor Interface

Graphical Display Window (E-Field Magnitude Display shown)All rotate, pan, and zoom view manipulations are available!

Side Window Similar to other modules.Contains coordinate fields,snap options, and drawingcommand prompts duringgeometry creation.

Field Calculator Icon Direct access to Field Calculator

Plot Menu (shown open) Most commonly used menu inFields Processor; plot fields, mesh,and pattern data, control animations,manage plots, etc.

Radiation Menu Compute far field or field ata specific distance (“near” or“EMI” fields), display antennaparameters

Geometry Menu Define additional geometry for post-processing (lines, cutplanes, face and object lists, etc.)

Data Menu Controls Source Excitations

Plotting the Mesh Choose Plot/Mesh to view the mesh

used in the solution At least one object must be Selected

Mesh plot options include: Scale Factor: Change size of

displayed triangles/tetrahedra Transparency: Set degree that

objects show through mesh Wire Frame, Hidden Line, or

Shaded options control the display type of the mesh

The Surface Only checkbox limits mesh plotting to the faces of selected objects

Post-Processor Excitations Excitations are controlled via the

Data/Edit Sources All ports or other sources can be

controlled Arbitrary magnitude and phase

combinations Excitation takes into account

symmetry planes used in model construction

Excitation defaults to 1 watt at {Source1}, assuming a “full” model geometry

Wattage is reduced by appropriate factor for symmetry

{Source1} could be Port1, Mode1; Gap Source 1, etc....

NOTE: If the Solution run is a FAST Sweep, the field excitation can also be tuned to different frequencies within the sweep range. Adaptive and Discrete Sweep solutions contain single-frequency field data only.

Post-Processor Eigenmode Excitation

For an Eigenmode solution, individual mode excitations can be viewed

Eigenmode excitations can not be viewed in combination

Field Values are Normalized to the peak data value

Since there is no actual ‘input’ into the model (voltage source, port, etc.) exciting the resonant field behavior, the field magnitudes are all scaled relative to a peak value of 1.0

Symmetry is again taken into consideration in excitation scaling

Mag E, First Eigenmode in Cylindrical Dielectric Resonator

Post-Processor Field Quantities

The 3D Post Processor can directly display the listed quantities

All units in MKS system, regardless of units used in geometry construction

e.g. E-field is in V/m, H-field in A/m, etc. Non-complex Magnitude quantities and all

Vector quantities can be Animated vs. Phase

Shows changing field on the display geometry as excitation phase is rotated

Most Quantities can be displayed on surfaces, along lines, and within 3D volumes

Other quantities not listed can be derived using the Field Calculator and displayed in the graphical window following calculation

Post-Processor Plot Geometry

All field plots are generated on Geometry The geometry list will include all objects built in the

3D modeler Surfaces of all 3D solids and 2D sheets Volumes of all 3D solids

Other default geometry for plotting are included Principle Plane cutplanes (XY, XZ, YZ)* Volume -all- (entire modeled volume) Animation Surfaces for multi-surface frame lists

The user can create additional geometry for plotting using the Geometry menu

Cutplanes and face lists create surfaces Line creates lines for integration, plotting

*NOTE: The principle plotting planes (XY, XZ, and YZ) will recognize changes to the local coordinate system while in the post-processor.

Plotting Fields To plot fields select Plot/Fields

Select a Plot Quantity in the left column

Select a Geometry on which to plot in the center column

(Optional) Select a Volume (domain) limit for plotting in the right column

For a single phase snapshot, enter desired phase and press OK (n/a for Cmplx quantities)

For Phase Animation, check the box and press OK

A plot settings dialog will launch with different entries depending upon the Quantity and Geometry selected (see next slide)

NOTE that the above Plot Quantities can all be classified as containing either scalar or vector data

Plot Settings Dialogs: Stills

Scalar Surface and Volume plots differ only in ability to fill in color maps

Requesting a plot of a scalar value along a line results in a 2D graph, rather than a colormap plot in the graphcial display window

Plot Settings Dialogs: Animation

Selecting any AnimSurf entry in the On Geometry column results in a series of snapshots at different planar or object surface faces in the model

The appropriate variable will be given in the top field; user sets start, stop and step limits

Selecting the Phase Animation button results in display of multiple field plots (each at a different excitation phase) on the same geometry.

The variable is Phase; user sets limits Checking the Store Frames button saves the

snapshots as a separately viewable plots Stored Frame Lists contain full plots that can

be viewed from alternate angles, zooms, etc, and are maintained in memory until manually deleted (see Plot Management, next slide).

Leaving Store Frames unchecked creates a screen animation, which cannot be viewed from different orientations after creation, and is auto-matically deleted after the display is dismissed.

Dialog for “AnimSurf XY” selection(Variable is Z position of XY planes)

Dialog for Phase Animation

Plot Management All 3D Field Plots are maintained in local memory, and can be

managed during your post-processing session Plots can be Saved and Opened in later sessions

Field views (scalar colormaps or vector plots) are saved as 3D Plots, while Graphs (plots of scalar quantities along lines) are saved as 2D Plots

Modify allows you to re-select the settings for any currently open plot

Visibility allows you to show or hide any currently open plot.

Plots which are hidden are still in memory Delete allows you to remove any currently open (visible or

hidden) plot from memory. To see the same plot again, you will have to re-create

the plot using the Field pick in the Plot menu The Animation menu pick allows management of various

frame lists created using Store Frames It can also be used to assemble user animations from

any available individual plots!

Antenna and EMI Processing: Computing Fields Projects with some form of open exterior

boundary condition (either radiation or PML) can have fields calculated external to the modeled space.

Fields are computed using the Radiation menu, selecting Compute...Far Field or Near Field

Far Field is the field at a radius of infinity from the model’s global origin

Near Field permits a user-entered radius

Fields are computed over user-specified angular ranges in phi and theta

Once computed, the fields are saved and may be plotted

If a plot of a near/far field cut outside of the computed range is desired, the fields will need to be re-computed first

Antenna and EMI Processing: Displaying Computed Fields

Computed fields are plotted using the Plot menu, Far Field or Near Field

Plot dialog permits plotting of antenna gain, directivity, axial ratio, polarization ratio, rE component fields, and rE total fields

Plots may be polar 2D, Cartesian 2D or polar 3D.

Displayed patterns can be saved as 2D Plots under the Plot...Save menu selection

The field computation and plotting does take symmetry planes into account

Antenna and EMI Processing: Displaying Computed Parameters

Computed Near and Far Field results can also be displayed in tabular format, showing the peak E-field magnitudes and locations

Far Field parameters include Antenna Parameters such as

Beam Area Directivity Radiated Power Accepted Power Efficiency Maximum U (radiation

power density)

The HFSS Field Calculator

Allows manipulation of modeled fields in the entire problem region Permits direct access to , , and Poynting Vector with all real,

imaginary, and vector components Includes Scalar, Vector, Complex, Integration, and Differentiation

functions Results can be Output to Post-Processor Graphical Display window

for color maps, vector plots, or 2D Graphs Results can also be exported to external data files

Contains a large registry stack with standard RPN-type stack manipulation features

Push, Pop, Exchange, Rotate... Is Unique to Ansoft HFSS!!

EH

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Accessing the Field Calculator

The Field Calculator is accessed using either the tool icon or the Data/Calculator menu pick

Once open, the calculator is a separate window from the 3D Post-Processor, and can be moved off of the Post-Processor background, minimized, etc.

Field Calculator Stack The calculator stack builds from

the top down The top entry is the most

recently added, with subsequently older entries flowing downward

Stack manipulation buttons are located immediately beneath the stack display

Push duplicates the top entry Pop deletes the top entry RlDn and Rlup ‘rolls’ the

stack contents up or down Exch swaps the two top

entries Clear empties the stack Undo reverses the last

operation

NOTE: Most calculators using RPN and stack operation roll subsequent entries so that the bottom of the display is the latest value entered. The Ansoft Field Calculator uses the opposite convention. Therefore, to subtract 3 from 5, the stack might resemble:

Scl: 3Scl: 5

before the subtraction is performed, NOT the reverse as one might initially expect.

Field Calculator Data Types Field Calculator stack entries are all

classified by data type Available data types are:

Complex Vector Complex Scalar Complex Vector Scalar Volume Surface Line

The type of each stack entry is indicated with an abbreviation to the left of the stack entry

In some cases, certain mathematical operations require specific data types in specific positions in the stack

Field Calculator Layout

Field Calculator Functions are organized in columns, by classification

Input column functions create inputs[E-field, H-field, Poynting data, Geometry, Numerical values (scalar, complex, and vector), etc.]

General column functions work on most stack contents

Scalar column functions operate only on scalar quantities

Vector column functions operate only on vector quantities

Output column functions produce output from the calculator[graphs, color or vector displays, output files, integral evaluations, etc.]