Features Of LC 2.7
Model Creation and Editing Features
- Model viewing
- Multiple model viewports can be displayed to show several
orthogonal views of a model, or for comparing two models.
- View as a wire frame or solid model
- Viewing transformations (click and drag)
- Rotate about an axis
- Spin within a plane
- Pan up, down, side to side
- Zoom in and out
- Slice to view the obscured (inner) details
- Viewing distance (perspective)
- Block editing
The model is defined as a collection of blocks, which define material
properties, excitation, loads, and output calculations.
Blocks can be rectangular, cylindrical, or spherical.
- Parameter entry editing
- Create blocks by parameter entry
- Update blocks after parameter change
- Delete blocks
- Select a group of blocks
- Select by click and drag
- Select by matching parameter
- Select from list
- Click and drag editing
- Create a block
- Select blocks
- Move selected blocks
- Rotate selected blocks within viewing plane
- Resize selected blocks
- Cut or copy selected blocks
- Paste cut or copied blocks
- Modify all selected
- Multi-level Undo
- Snap-to-grid
- Reorder blocks to change stacking priority
- Work Preservation
- Save model to a file
- Automatic save at intervals
- Automatic save if program unexpectedly terminates
- Previous file revision saved as backup
- Model consistency checking
Each time a block is modified, a number of self-consistency
rules are checked, as well as global consistency validation.
The validation can be run manually as well.
- Reference notes
Notes can be saved into a model file to describe its
features, use, or simulation results.
Notes can be handy to save thoughts on a work-in-progress too.
FD-TD Simulation Features
- Grid Generation
A structured grid is automatically generated from the CAD model
and grid generation parameters.
The grid size is defined by the rectangular bounding box of the
model space.
The elements are brick-shaped, and can vary in size within the grid.
- Boundary Conditions
- Berenger Perfectly Matched Layers (PML) Absorbing Boundary Condition
This ABC results in much less reflection of outgoing energy
than the other abosorbing boundary conditions.
The current implementation does not allow dielectric materials
at the corners of the grid.
- Second order Mur Absorbing Boundary Condition
Requires the model to be completely enclosed within a buffer of
free space. Absorbs with much less reflection than the first order Mur,
but cannot handle complex materials at the grid boundary.
- First order Mur Absorbing Boundary Condition
Usable on all types of models.
This algorithm can result in a large percentage of the outgoing
energy being reflected from the boundary if materials with
high dielectric constants are present.
- Symmetry Boundary Conditions
Electric and Magnetic Walls
Any face of the grid can have an electric (tangential electric
field is forced to zero) or magnetic (tangential magnetic
field is forced to zero) boundary condition applied.
Useful for reducing the model size by using symmetry, especially
for arrays of identical elements.
- Material Parameters
The model can contain any number of homogeneous regions composed of
materials with user-defined properties.
- Relative Electric Permittivity
- Electric Conductivity
- Relative Magnetic Permeability
A selection of pre-defined materials are available.
- Internal Source Excitation
- Excitation Types
- Excitation Waveforms
- Gaussian pulse
- Ramp pulse
- Continuous sinusoid
- Modulated Gaussian pulse
- User defined from time-domain data
- Time delay before start of excitation
- Repeating pulse train
- Source excitation can be hard (forced magnitude, zero impedance),
soft (matching impedance by linear superposition), or
resistive (source resistance a constant).
- Non-periodic source waveforms can be truncated (eliminated from
the simulation as the waveform approaches zero) or infinite
(continuous for the simulated time).
- Plane Wave Source Excitation
Scattering problems can be simulated with a plane wave excitation
of arbitrary incident angle and polarization.
The scattered field is isolated by means of a total field/scattered
field boundary formulation at the outer layers of the grid.
- Load Region
- FD-TD load
A resistive load can be simulated internally within FD-TD.
- SPICE load
Can be any SPICE circuit.
SPICE is automatically executed when a SPICE load is defined.
SPICE circuits can contain an arbitrary number of ports
(interconnection points within the FD-TD simulation).
- Interactive Feedback
Time domain probe values can be displayed as X-Y plots updated
as the simulate progresses (point and line probes),
and viewed as color shaded images or contour lines (plane and
surface probes).
- Simulation Control
- Iteration
The simulation can proceed for a defined interval, and then be
continued or terminated.
- Interrupt
The simulation can be interrupted at any point. While the
simulation is interrupted, partial results and the current
state of the electromagnetic fields can be examined.
- Checkpoint and Restore
The state of the simulation can be saved to a file, then the
simulation can be restarted at the same point at a later time.
- Parallel Processing
The use of multiple processors during the simulation reduces
the time to solution.
The user only specifies the number of processors to use.
The problem is automatically partitioned among the processors.
- Parameter variation scripts
Execute commands from an input file to perform the same editing and
simulation functions available in interactive usage.
This feature is used to vary model parameters for a set of simulations.
Analysis Features (simulation results and post-processing)
- Time Domain Probes
- Types of output
- Vector field output
- Electric field
- Magnetic field
- Current density (del cross H)
- Power density (E cross H)
- Integral values
- Voltage (line integral of electric field)
- Current (closed loop integral of magnetic field)
- Magnetic flux (surface integral)
- Charge (closed surface integral)
- Shapes of probes
- Point
A single value per time step
- Line
An array of values per time step
- Plane
A two dimensional matrix of values per time step
- Surface
A set of planes defined by a complex structure
- Data reduction
- Center
If a region is given, only the center value is reported
- Average
If a region is given, the values throughout the region
are averaged, and that value is reported
- Output formats
- X-Y plot, one point per time step
From point probes
- X-Y plot, a curve for each time step
From line probes
- A 2-D color shaded or contour line image for each time step
For plane probes
- Values mapped into a 3-D space (Movie.BYU format)
For plane or surface probes
- Algebraic Probe Calculator
Time-domain probe values can be combined with algebraic operators
and math functions like square root and log.
Derivative with respect to time is also available.
Math can be performed on time-domain waveforms, or
spatial (plane probe) data.
Calculations can be performed at simulation time, or as post-processing.
- Scattering Parameters
Frequency domain data measuring incident, reflected, and transmitted
waves can be used to calculate S-parameter magnitude plots.
- Far Field Radiation/Scattering Data
If a plane wave excitation is used, the resulting data is for the
scattered field.
If a source internal to the model is used, then the far field data
is for the total field.
- Angle Sweeps
The radiation pattern can be plotted for angular sweeps
around the model.
- Frequency Sweeps
The radiation pattern can be plotted for a range of frequencies
of interest.
- Components
The far field data can be total magnitude, or magnitude and
phase for the separate phi and theta components.
- Normalization
The far field data can be normalized versus the model source excitation
waveform, and reported on a decibel scale.
Other Features
- Convert into mesh
The blocks of the model are converted into FD-TD cells,
which can then be edited to produce complex shapes or
other special effects.
Copyright © Cray Inc.
Maintained by Kevin Thomas (kjt@cray.com).
Last modified
Wed Oct 13 09:05:27 CDT 1999