DEFINE MENU

7 DEFINE MENU

DEFINE CALCULATIONS DIALOG

DEFINE COLORS DIALOG

DEFINE MATERIALS DIALOG

DEFINE MODEL DIALOG

DEFINE MULTIPORTS DIALOG

DEFINE PULSES DIALOG

DEFINE FAR FIELD SWEEPS DIALOG

The define menu dialogs allow you to create and modify model data which does not have a visual representation. Most of these settings are optional, although the materials and model parameters dialogs are frequently used.

Calculations...	Define and modify calculations.
Colors...	Define the color map used for shading the plane and surface probes.
Materials...	Define and modify materials.
Model Pameters...	Define model parameters.
Multiport Loads...	Define multiport loads.
Pulses...	Define pulses from probe outputs for frequency domain analysis.
Far Field Sweeps...	Define far field calculations.

7.1 DEFINE CALCULATIONS DIALOG

A calculation is an arithmetic expression of probes. For example, two voltage probes can be added together to get a total voltage calculation. A voltage can be multiplied by a current to get a power calculation. Calculations themselves become another type of probe, and may be used in subsequent calculation definitions, and can be plotted with the Plot Probes dialog.

7.1.1 VALUES FRAME

The parameters for the calculation selected from the list are displayed in the values frame. These parameters can be modified and a calculation updated with the Replace button, or a new calculation can be created with the Add button.

Name	The name of the calculation.
Equation	The algebraic expression to be evaluated.
Plot Save Output File Format Image Scale Time Factor Space Factor	These fields are the same as for a probe.

7.1.2 ACTION AREA

Add	Create a new calculation definition from the current values.
Delete	Delete the currently selected calculation.
Replace	Update the selected calculation with the current values.
Reset	Reset the current values to the selected calculation values.
Clear	Clear the current values.

7.1.3 KEYPAD FRAME

The keypad frame can be used to enter an equation, rather than entering it in directly to the Equation field. Probes and sources are listed. Selecting a name from the list inserts it into the equation. Similarly, the numeric and function keypad can be used to add to an equation.

Output	Select the probe output types to be displayed in the selection list. When a list item is selected, it is added to the end of the current calculation equation.
+ - / * ( )	These operators are used to form the equation.
abs	Absolute value
trunc	Integer value
ln	Natural log
exp	Inverse log (e^x).
log10	Log base 10
sqrt	Square root
SP	Insert a space. All arguments and operators must be separated by spaces. Keypad operators insert spaces automatically, so addition spaces are not necessary, but spaces are required before and after constants.

7.2 DEFINE COLORS DIALOG

The Define Colors dialog allows you to modify the image color palette. These colors are used to display the plane probes in a viewport during a simulation.

The colors are distributed in ranges, with each range assigned a relative weight. A larger weight value will result in more cells within that color range. A value of zero eliminates that color range from the image. The default is linear weighting for the colors.

Some systems do not allow colors to be modified in this way, and then this dialog has no effect.

Blue Cyan Green Yellow Red	Percentage weight for the color. Colors with a larger relative weight contribute more to the palette used to color the plane probes.
Brightness	Color brightness factor. 50% is normal brightness, 100% is white, 0% is black.
Reset To 50	Reset all values to defaults.
Spread To Active Probe	Spread the colors evenly across the values of the probe that is displayed in the editing area of the main window. This will often give a pleasing distribution unless the values are extremely clustered. Spreading does not include values clipped by the Range Min, Range Max, and Noise Limit values of the probe, so by setting those values first, the distribution range can be controlled.

7.3 DEFINE MATERIALS DIALOG

The Define Materials dialog displays a list of currently defined materials. To edit a currently defined material, select it from the list of materials. Since materials are not a type of block, they are not displayed in a viewport. The first material in the list is the default material of the mesh, if no material is explicitly defined as a default.

Name	The name of the material.
Color	The default color for blocks created of this material.
Fill	The deafult fill pattern for blocks created of this material.
Permittivity	The relative electric permittivity of the material.
Conductivity	The electric conductivity of the material.
Permeability	The relative magnetic permeability of the material. If this value is not 1 for any material, then extra memory must be allocated during the simulation to account for the magnetic properties of the material.
Add	Create a new material definition from the current values.
Delete	Delete the currently selected material.
Replace	Update the selected material with the current values.
Reset	Reset the current values to the selected material values.
More Materials	A list of common materials with typical parameters is provided (see below).
Select Materials From Model File	Pressing this button brings up an Open Model File dialog. After another model is opened, its materials can be imported into the current model.

7.3.1 Materials in the More Materials List

Air	Metal	BT	FR4 Epoxy	Aluminum
Bakelite	Beryllium	Brass	Bronze	Cast iron
Chromium	Cobalt	Copper	Diamond	Ferrite
Free Space	Gallium Arsenide	Glass	Gold	Graphite
Iron	Marble	Mica	Nickel	Palladium
Platinum	Polyamide	Polystyrene	Porcelain	Quartz Glass
Hard Rubber	Sapphire	Silicon	Silicon Dioxide	Silver
Solder	Stainless Steel	Tantalum	Teflon	Titanium
Tungsten	Distilled Water	Fresh Water	Sea Water	Zinc

7.3.2 DEFINE MATERIALS OPEN DIALOG

Select a model file using the Open Model File dialog.

7.3.3 DEFINE MATERIALS LIST DIALOG

The list of materials from the model opened is displayed in the Define Materials LIST dialog. To import a material definition, select it from the list, then press the Add button in the Define Materials dialog.

7.4 DEFINE MODEL DIALOG

The Define Model dialog controls the parameters that can be set for the model.

7.4.1 MODEL PARAMETERS FRAME

These parameters should be set before the model is constructed, as these values are used during block editing.

Minor Grid Spacing	This value defines the minimum dimension size for the model. All coordinates and model dimensions are rounded to a multiple of this value. As a special case, 0 means no rounding. When the View menu Show Grid option is enabled, then orthogonal views of the geometry display the grid points as small dots.
Major Grid Factor	This defines a multiple of the minor grid spacing for larger marks when the View menu Show Grid option is enabled. For example, if the major grid factor is 10, then every 10th grid point is displayed as a large mark.
Measurements Units	This defines the units of measure for model dimensions. For the purposes of model creation, the measurement units are irrelevant, since the model dimensions are relative. For purposes of simulation, physical dimensions must be applied.

7.4.2 MESH GENERATION FRAME

These parameters are used when a simulation is run. The first step in the simulation is creation of the computational mesh, and is called mesh generation.

X Cell Size Y Cell Size Z Cell Size	The size of each cell of the mesh, given in the units of the model. This value strongly influences the size and accuracy of the simulation. A smaller value will result in a larger but more accurate simulation. The default value is the minor grid spacing of the model.
Cubic Cells	If this toggle is set, only the X Cell Size parameter can be set, and the other two cell dimensions are automatically set to the same value. If the toggle is not set, then all three values can be specified, creating rectangular cells.
Default Material	The name of the default material of the grid. The default material fills in the undefined regions of the grid. This is required because the grid is always a rectangular box, but the model need not be. The default if none is selected is the first material of the material list, which is normally air (free space).
Output Directory	The directory in which to create the output files such as probe values during a simulation. If the directory does not exist, it is created when a simulation is started. The default is the current directory.

7.4.3 BOUNDARY CONDITIONS FRAME

Each face of the grid is truncated with a boundary condition that may be absorbing (simulating an infinite extension of the grid), an electric wall (zero tangential electric field) or magnetic wall (zero tangential magnetic field). Electric and magnetic walls may be used to enforce a symmetry condition for arrays of identical cells.

If an absorbing boundary condition is desired, one of the available ABC types should be selected. The default is a first order accurate Mur ABC.

Absorbing	Outgoing energy is absorbed.
Electric	Tangential electric fields are set to zero at the boundary.
Magnetic	Tangential magnetic fields are set to zero at the boundary.
ABC Type	Absorbing boundary condition to be used if any grid face boundary condition is set to absorbing.
PML Thickness	The thickness of the PML absorbing boundary layer, in cells. A thicker layer will reflect less energy than a thin layer, but use more memory and CPU time. Recommended range is 4 to 12.
PML Order	The order of the PML update.
PML Tolerance	The maximum relative reflection from the outer boundary of the PML layer. A lower tolerance will result in higher attentuation of the outgoing energy.

Absorbing Boundary Condition Types

None	No absorbing. All energy is reflected inward.
First Order Mur	The default absorbing boundary condition. First order accurate in time and space. Can be used with complex dielectric materials and non-uniform meshing.
Second Order Mur	Second order accurate in time and space. More accurate than the first order Mur, but can only be used with homogeneous dielectric regions and uniform meshing.
PML	Berenger perfectly matched layers. The most accurate absorbing, which can be tuned by setting the PML parameters. Requires more memory and computation than the Mur boundary conditions.

7.4.4 PLOT PARAMETERS FRAME

These parameters are used when creating the frequency domain data for pulse definitions.

Maximum Frequency	This is the maximum frequency that is displayed on the frequency domain plots. The default is three times the maximum source frequency. Once any plots are read, this parameter should not be modified.
Frequency Count	This is the number of points from 0 Hz to the maximum frequency in the frequency domain plots. The default value is the number of points in the time domain plot.

7.4.5 FAR FIELD PARAMETERS FRAME

Except for the Normalization Source, these field has been superceded by the settings in the Define Far Field Sweeps dialog. These parameters will be removed in a future version of LC.

Normalization Source	If specified, the far field sweep data will be normalized to this source. The default is to calculate unnormalized far field data.
Minimum Frequency	The lowest frequency of interest.
Maximum Frequency	The highest frequency of interest.
Frequency Count	This is the number of points from the minimum to the maximum frequency in the output plot.
Total Power File	The file name for the total radiated power plot data

Press "OK" to accept the changes, or "Cancel" to reject the changes and keep the previous selections.

7.5 DEFINE MULTIPORTS DIALOG

The Define Multiport Loads dialog defines the loads associated with the port blocks.

A multiport load is an element which interacts with the electromagnetic fields within the simulated model at multiple physical locations. The locations are ports, which are tied to a multiport by the multiport name. If only one port references a multiport, then the multiport is a single port load. If two ports reference it, it is a two port load, and so on.

The multiport load's interaction with the model is defined by its SPICE circuit file. This file is simulated by SPICE during the electromagnetic simulation. The SPICE circuit can contain arbitrary circuit elements. During simulation, the circuit file is converted into a SPICE subcircuit, and each port node name corresponds to an external node of the subcircuit.

To edit a currently defined multiport, select it from the list of multiports. Since multiports are not a type of block, they are not displayed in a viewport.

Name	The name of the multiport.
Spice Circuit File	The name of the file containing the Spice circuit defining the load.

7.5.1 Action Area

Add	Create a new multiport definition from the current values.
Delete	Delete the currently selected multiport.
Replace	Update the selected multiport with the current values.
Reset	Reset the current values to the selected multiport values.

7.5.2 Ports Referencing This Load

This is a list of all of the ports which reference this multiport load. This information is displayed so that you may verify that the port blocks are defined correctly for the multiport load.

7.6 DEFINE PULSES DIALOG

The Define Pulses dialog defines the grouping of probes to pulses. Pulses are used to produce frequency domain results, as well as for convenience in time domain results that require more than one probe (such as time domain impedance).

Pulse groupings are not arbitrary. The probes which define the pulse must measure values within the same region of the model. Generally, probes from distant regions of the model are not grouped together as one pulse. A single probe may appear in more than one pulse definition. For example, a probe may measure both an incident pulse, and a reflected pulse.

To produce frequency domain results, the probes must be windowed in time to define a pulse. This windowing is used to separate an incident pulse from a reflection, as well as to reduce the. amount of computation in the DFT (discrete Fourier transform) calculation.

To edit a currently defined pulse, select it from the list of pulses. Since pulses are a grouping, not a type of block, they are not displayed in a viewport.

Name	The name of the pulse.
Voltage Current Charge Magnetic Flux	The probe names for the voltage, current, charge, and magnetic flux probes. The probe name can be entered directly into the text field, or selected from a list of defined probes of the corresponding type via a drop-down list. Probes may also be selected in any viewport, or the View Blocks dialog.
Pulse Start	Start time step of the pulse. Along with Pulse End, this defines the window in time in which the probe is measuring the pulse of interest.
Pulse End	End time step of the pulse.
Guess From Data	This button invokes an algorithm that examines the plot data and determines the start and end times of the pulse based on the time of the probe peak value.
Set From Graph	This button sets the pulse start and end times by reading the times from the feedback plot. The feedback plot can be adjusted with button drags, as described below.
Group Loose Probes	This convenience function searches the list of defined probes and creates new pulse definitions for any probes that are not currently in one. The grouping of different probe types into a pulse definition is based on the order of the probes in the block list.
Guess All Pulse Times	This function is the same as performing the Guess From Data function on all of the defined probes.

7.6.1 Action Area

Add	Create a new pulse definition from the current values.
Delete	Delete the currently selected pulse.
Replace	Update the selected pulse with the current values.
Reset	Reset the current values to the selected pulse values.

7.6.2 Feedback Plot

Below the action area is a small plot of one of the probes. This plot has been cropped to reflect the pulse start and end time steps, and is used as feedback to adjust those values.

New start and end points for the plot can be set by a button 1 drag within the plot area. The maximum limits can be restored by a button 2 click. The Set From Graph button can be used to read the current values from the graph and make them the new start and end times for the pulse.

7.7 DEFINE FAR FIELD SWEEPS DIALOG

Far field sweeps calculate sums of energy radiating out of the computational grid. A far field sweep can collect far field data over a range of angles, or a range of frequencies, or both.

Angle sweeps are given by spherical coordinate phi and theta angle ranges. Phi defines an angle in the X-Y plane, where 0 degrees reports the energy radiating out along the positive X-axis and 90 degrees is along the negative Y-axis. Theta defines an angle from the positive Z-axis, where 0 degrees is along the positive Z-axis and 90 degrees is in the X-Y plane.

Frequency ranges can be set separately for each sweep, but grid face data is saved for each distinct frequency of interest, so a considerable amount of extra memory and CPU time is required as the total number of frequencies increases.

By default, the result is summed from all six grid faces. For specialized problems, some grid face sums can be removed from the calculation via the Grid Face Enable selections. If a grid face is disabled, the values for that face are ignored during the calculation. For example, a grid face may be disabled if that face of the model is being used as an antenna ground plane.

Name	The name of the far field sweep definition.
Disable Sweep	If this toggle is set, the sweep is ignored when a simulation is run.
Output File	The output file name. The default is the sweep name.
Magnitude Values in dB	The magnitude values are converted to decibels (10*log10). This is useful if the normalization source has been set in the Model Parameters dialog.
RCS	RCS computed as sqrt(phi^2 + theta^2).
Phi Component	The phi component of the radiating energy.
Theta Component	The theta component of the radiating energy.
Total Radiation	The sum of the radiating energy for all angles.
Grid Face Data	Save the raw data from the grid face, rather than reporting phi and theta component sums. This output results in a modified X-Y plot file which cannot be read by LCPlot.
X-Axis Sweep	Variable to be plotted on the X-axis of the result.
Second Sweep	A second variable to create a family of curves.
Third Sweep	A third variable to create a family of curves for each value of the variable.
Phi Angle Parameters	The starting and ending angles for a phi angle sweep, plus the increment defining the number of look angles. If no phi sweep is desired, this is a single angle.
Theta Angle Parameters	The starting and ending angles for a theta angle sweep, plus the increment defining the number of look angles. If no theta sweep is desired, this is a single angle.
Frequencies of Interest	The starting and ending frequencies of interest, plus the frequency increment and number of frequencies. Either the increment or the count can be set, and the other is automatically computed.
Grid Face Enable	The grid faces to participate in the calculation.