Ansoft Corporation

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Ansoft HFSS 3D Post Processor and Calculator
Ansoft Corporation Four Station Square, Suite
200 Pittsburgh, PA 15219-1119 USA [phone]
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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

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HFSS 3D Post-Processor Interface
Field Calculator Icon Direct access to Field
Calculator
Data Menu Controls Source Excitations
Radiation Menu Compute far field or field at a
specific distance (near or EMI fields),
display antenna parameters
Side Window Similar to other modules.Contains
coordinate fields,snap options, and
drawingcommand prompts duringgeometry creation.
Plot Menu (shown open) Most commonly used menu
in Fields Processor plot fields, mesh, and
pattern data, control animations, manage plots,
etc.
Geometry Menu Define additional geometry for
post-processing (lines, cutplanes, face and
object lists, etc.)
Graphical Display Window (E-Field Magnitude
Display shown) All rotate, pan, and zoom view
manipulations are available!
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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

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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.
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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
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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

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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.
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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
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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
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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
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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!

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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 models 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

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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

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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)

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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!!

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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.

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

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Field Calculator Layout

• Field Calculator Functions are organized in
  columns, by classification
• Input column functions create inputsE-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
  calculatorgraphs, color or vector displays,
  output files, integral evaluations, etc.