6.%20Electromagnetics%20Enhancements

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6. Electromagnetics Enhancements
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Electromagnetics Enhancements

• Emag focus in ANSYS 5.7 is on high-frequency
  electromagnetics (discussed next).
• Other Emag enhancements
• LMATRIX (inductance calculation) improvements
• Output array contains the NxN inductance matrix
  (as before) and a new N1th column containing
  flux linkage values, with the I th row
  corresponding to the I th coil.
• SENERGY (magnetic energy calculation) is more
  robust, accurate, and faster.

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Electromagnetics Enhancements

• Other Emag enhancements (cont'd)
• New diode element, CIRCU125
• To simulate a common or Zener diode.
• Can interface with circuit element CIRCU124,
  transducer element TRANS126, and mechanical
  elements MASS21, COMBIN14, and COMBIN39 for
  coupled-field analyses.
• Can be defined using the circuit builder.

CIRCU125
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High Frequency Electromagnetics

• Overview
• In ANSYS, HF Electromagnetics is used to simulate
  the full wave electromagnetic phenomena.
• RF/microwave problems (interior wave propagation)
• Radiation and scattering problems (exterior wave
  propagation)
• Available in ANSYS/Multiphysics and ANSYS/Emag
  HF products.
• HF solution is in the frequency domain.
• No limit on the highest frequency allowed.

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High Frequency Electromagnetics

• Overview (cont'd)
• Major components of a HF FEA model

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High Frequency Electromagnetics

• Overview (cont'd)
• ANSYS 5.7 takes a major leap in HF simulation
  capabilities with several new features and
  enhancements
• New boundary conditions
• PML (perfectly matched layer), impedance
• New excitations
• Waveguide ports plane wave surface magnetic
  field, surface electric field, and current
  density excitations
• Elements
• New HF118 element, enhancements to HF119 HF120
• Solvers and postprocessing

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HF Electromagnetics - New BC'sPML

• Perfectly Matched Layer (PML)
• Absorbing layers of elements used for the
  truncation of the HF FEA domain.
• Reduce the FEA domain significantly by replacing
  the outer computation domain (infinite) with an
  absorbing layers.
• Required in many real world applications
• Exterior phenomena, e.g, antenna and EMC/EMI
  problems.
• Interior phenomena, e.g, waveguides and
  transmission lines.

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HF Electromagnetics - New BC's PML

• PML region is simply a layer (or layers) of
  elements placed at the boundary of the field
  domain.
• Elements used are 119 and 120 with KEYOPT(4) 1.
  For example ET,2,HF120,,,,1
• Extend the material properties in the field
  region into PML
• PML supports symmetry boundary conditions

Schematic of cross section of a 3D PML region
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HF Electromagnetics - New BC's PML

• Recommendations
• PML boundary edges should be parallel to global
  Cartesian or Cartesian ESYS.
• Thickness of PML region gt 0.25wavelength.
• Allow at least 4-5 layers of elements in
  surrounding field as buffer zone between device
  and PML.
• Four elements through the thickness of PML region
  for - 50 Db attenuation. More attenuation
  can be obtained by adding more PML layers.

PML2
PML2
ESYS2
ESYS2
PML1
PML1
Schematic of 1D PML layers
ESYS1
ESYS1
ESYS3
PML3
PML3
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HF Electromagnetics - New BC'sImpedance

• Four types of impedance BC's are now available
• Far-field radiation boundary
• Air-dielectric boundary
• PEC (perfect electric conductor) surface with
  dielectric coating
• Non-PEC surface
• Apply using SF family of commands

air-dielectric Interface
surface of non-perfect conductor
dielectric
non-perfect conductor
far-field boundary
air
PEC with dielectric coating
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HF Electromagnetics - New ExcitationsWaveguide
Ports

• New parallel-plate waveguide
• Can be used to simulate problems like
  micro-strip.
• All four types of waveguides
• Z axis can be in either the wave propagation
  direction or the opposite direction. X-axis must
  be parallel to width of port.
• Origin for rectangular waveguide is at center,
  different from 5.6.

new
Rectangular Waveguide
Parallel-Plate Waveguide
Circular Waveguide
Coax Waveguide
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HF Electromagnetics - New Excitations...Waveguide
Ports

• Higher-order modes are now available at 5.7

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HF Electromagnetics - New Excitations...Waveguide
Ports

• HFPORT,Portnum,Porttype,Local,Mode,Portbc, VAL1,VA
  L2,VAL3,VAL4,VAL5
• New HFPORT command replaces PORTOPT.
• Port boundary conditions by Portbc in HFPORT
• IMPD Matching the impedance of the single mode.
• SEXT Terminating the port w/ PML layers. An
  invisible port to extract S-parameters.
• SOFT Equivalent current excitation. Allow
  multiple ports multiple modes. Can extract
  S-parameter.
• HARD Fixed electromagnetic field at port.

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HF Electromagnetics - New Excitations...Waveguide
Ports

• Schematics of four Portbc options for waveguides
  in HFPORT command

PML2
PML1
incident wave
SOFT
HARD
incident wave
incident wave
incident wave
reflection wave
reflection wave
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HF Electromagnetics - New ExcitationsPlane Wave

• New PLWAVE command replaces PLANEWAVE
• PLWAVE, EX, EY, EZ, AngX, AngZ
• EX, EY and EZ are the electric field amplitudes
  in X, Y and Z directions.
• AngX and AngZ are the angles of the wave to
  X-axis and Z-axis.
• Used for scattering analysis in EMC/EMI analysis

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HF Electromagnetics - New ExcitationsSource Terms

• You can now specify the following excitation
  sources (using the BF family of commands)
• Magnetic field (H) at a surface.
• Electric field (EF) at a surface.
• Current density (JS) at a point, line, surface,
  or volume.

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HF ElectromagneticsElement Enhancements

• New 2.5-D, 8-node HF118 element
• Extract eigenvalues of guided wave structures
  (waveguides or transmission lines).
• Applicable for modal analyses (Block Lanczos).
• Quadrilateral or triangular shapes.
• Both 1st order and 2nd order available.
• To calculate cutoff frequencies and propagating
  constants used together with HFEIGOPT.

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HF Electromagnetics Element Enhancements

• HF119 (10-node tet) gets new 2nd-order option
• Applicable to both modal and full harmonic
  analyses
• Keyopt(1) 2
• Better accuracy compared with 1st order element,
  especially for complex geometry
• HF120 (20-node brick) gets improved 2nd-order
  option
• DOFs from 36/element to 54/element
• Complete vector basis functions
• Better accuracy for higher-order modes

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HF ElectromagneticsSolution and Postprocessing

• Sparse solver is now the default (not frontal).
• ICCG and FRONTAL also available as before
• Choosing analysis types
• Harmonic analysis (Antype, harmic) HFSCAT,SCAT
  must be specified for RCS calculation
• Modal analysis (Antype,modal) 3D or 2D
  modal analysis

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HF Electromagnetics Solution and Postprocessing

• New commands to review far-field results
• PLHFFAR to display the electromagnetic far field,
  radar cross-section (RCS), and antenna pattern
  (PATT)
• PRHFFAR for listings

• RCS of a metal plate with incident plane wave

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HF Electromagnetics Solution and Postprocessing

• New HFNEAR command to calculate near-field
  results (EF H).
• Options to calculate at a specified point or
  along a path.
• New PRHFFAR calculates/prints far field beyond
  FEA domain.
• Other
• HFSYM to set symmetry planes for postprocessing
  calculations in near and far field
• Current density can be shown graphically
• Calculated parameters
• SPARM magnitude and phase angle of S-parameter
  (both single and multiple ports)