Changes

EM.Cube’s MoM3D module offers two distinct 3D MoM simulation engine. The first one is a Wire MoM solver that can be used to simulate wireframe models of metallic structures. This solver is particularly useful for modeling wire-type antennas and arrays. The second engine features a powerful surface MoM solver. It can model metallic surfaces and solids as well as solid dielectric objects. The Surface MoM solver uses a surface integral equation formulation of Maxwell's equations. In the case of solid dielectric objects, equivalent electric and magnetic currents are assumed on the surface of the dielectric object to formulate the interior and exterior boundary value problems.

The Green’s functions are the analytical solutions of boundary value problems when they are excited by an elementary source. This is usually an infinitesimally small vectorial point source. In order for the Green’s functions to be computationally useful, they must have analytical closed forms. This can be a mathematical expression or a more complex recursive process. It is no surprise that only very few electromagnetic boundary value problems have closed-form Green’s functions. The total electric ('''E''') field can be expressed in terms of the electric current in the following way:

where [[Image:/files/images/manuals/emagware/emcube/modules/mom3d/an-overview-of-3-d-method-of-moments/free-space-greens-function/i_tn.gif]] is the unit dyad, [[Image:/files/images/manuals/emagware/emcube/modules/mom3d/an-overview-of-3-d-method-of-moments/free-space-greens-function/delta_tn.gif]] is the gradient operator, '''r''' and '''r'''' are the position vectors of the observation and source points, respectively, and k₀ is the free-space propagation constant. This implies that electromagnetic waves propagate in free space in a spherical form away from the source. Note that the Green’s function has a singularity at the source, i.e. when '''r''' = '''r''''. This singularity must be removed when solving the integral equations.

In the more general formulation of the field integration equations, both electric and magnetic currents are included. In that case, the total electric and magnetic fields are given by the following equations:

where [[Image:/files/images/manuals/emagware/emcube/modules/mom3d/an-overview-of-3-d-method-of-moments/3-d-integral-equations/05_3d-integrals_tn.gif]] is the boundary value operator for the electric field and [[Image:/files/images/manuals/emagware/emcube/modules/mom3d/an-overview-of-3-d-method-of-moments/3-d-integral-equations/05_3d-integrals_tn.gif]] is the boundary value operator for the magnetic field. For example, they may require that the tangential components the '''E'''field vanish on perfect electric conductors. Or they may require that the tangential components the '''E''' and '''H''' fields be continuous across an aperture in a perfect ground plane. Given the fact that the dyadic Green’s functions and the incident or impressed fields are all known, one can solve the above system of integral equations to find the unknown currents '''J''' and '''M'''. Therefore, through these relationships you can easily cast the above integral equations in terms of unknown '''E''' and '''H''' fields.

The integral equation derived in the previous section can be solved numerically by discretizing the computational domain using a proper meshing scheme. The original functional equation is reduced to a set of discretized linear algebraic equations over elementary cells. The unknown quantities are found by solving this system of linear equations, and many other parameters can be computed thereafter. This method of numerical solution of integral equations is known as the Method of Moments (MoM). In this method, the unknown electric current is represented by an expansion of basis functions as follows:

where [Z]-1 is the inverse of the impedance matrix and [V] is the excitation vector.

Wire structures are made of linear PEC elements. These may consist of actual physical wires such as a dipole or loop antenna or a wireframe representation of a surface or solid object. In a wire structure, the unknown electric currents are one-dimensional. The integral equation is derived by forcing the tangential component of the electric field to vanish on the surface of the wire. This leads to the following simpler integral equation:

where [[Image:/files/images/manuals/emagware/emcube/modules/mom3d/an-overview-of-3-d-method-of-moments/pocklingtons-integral-equation-for-wire-structures/15_pocklingtons_tn.gif]][[files/images/manuals/emagware/emcube/modules/mom3d/an-overview-of-3-d-method-of-moments/pocklingtons-integral-equation-for-wire-structures/15_pocklingtons.gif|files/images/manuals/emagware/emcube/modules/mom3d/an-overview-of-3-d-method-of-moments/pocklingtons-integral-equation-for-wire-structures/15_pocklingtons.gif]] is the free space Green’s function, I(l) is the unknown linear current in the wire and C is the contour of the wire. [[Image:/files/images/manuals/emagware/emcube/modules/mom3d/an-overview-of-3-d-method-of-moments/pocklingtons-integral-equation-for-wire-structures/16_pocklingtons_tn.gif]][[files/images/manuals/emagware/emcube/modules/mom3d/an-overview-of-3-d-method-of-moments/pocklingtons-integral-equation-for-wire-structures/16_pocklingtons.gif|files/images/manuals/emagware/emcube/modules/mom3d/an-overview-of-3-d-method-of-moments/pocklingtons-integral-equation-for-wire-structures/16_pocklingtons.gif]] and [[Image:/files/images/manuals/emagware/emcube/modules/mom3d/an-overview-of-3-d-method-of-moments/pocklingtons-integral-equation-for-wire-structures/17_pocklingtons_tn.gif]][[files/images/manuals/emagware/emcube/modules/mom3d/an-overview-of-3-d-method-of-moments/pocklingtons-integral-equation-for-wire-structures/17_pocklingtons.gif|files/images/manuals/emagware/emcube/modules/mom3d/an-overview-of-3-d-method-of-moments/pocklingtons-integral-equation-for-wire-structures/17_pocklingtons.gif]] are the unit vectors along the wire contour. Note that [[Image:/files/images/manuals/emagware/emcube/modules/mom3d/an-overview-of-3-d-method-of-moments/pocklingtons-integral-equation-for-wire-structures/15_pocklingtons_tn.gif]][[files/images/manuals/emagware/emcube/modules/mom3d/an-overview-of-3-d-method-of-moments/pocklingtons-integral-equation-for-wire-structures/15_pocklingtons.gif|files/images/manuals/emagware/emcube/modules/mom3d/an-overview-of-3-d-method-of-moments/pocklingtons-integral-equation-for-wire-structures/15_pocklingtons.gif]] has a singularity when r = r’, which must be either removed or avoided as will be explained later.

The right choice of the basis functions that are used to represent the elementary currents is very important. It will determine the accuracy and computational efficiency of the resulting numerical solution. Rooftop basis functions are one of the more popular types of basis functions used in a variety of MoM formulations. The simplest rooftop function is the one-dimensional triangular functions defined as in the figure below:

where l is the length coordinate along the wire with l=0 at its start point. [[Image:/files/images/manuals/emagware/emcube/modules/mom3d/an-overview-of-3-d-method-of-moments/meshing-and-discretization-of-wire-structures/21_meshing_tn.gif]] is the scaled and translated version of the linear basis function f(l) shown in the previous figure. [[Image:/files/images/manuals/emagware/emcube/modules/mom3d/an-overview-of-3-d-method-of-moments/meshing-and-discretization-of-wire-structures/22_meshing_tn.gif]] is the unit vector along wire.

EM.Cube's MoM3D Module features two different simulation engines: Wire MoM and Surface MoM. Both simulation engines can handle metallic structures. The Wire MoM engine models metallic objects as wireframe structures, while the Surface MoM engine treats them as perfect electric conductor (PEC) surfaces. The PEC objects can be lines, curves, surfaces or solids. All the PEC objects are created under the '''PEC''' node in the '''Physical Structure''' section of the Navigation Tree. Objects are grouped together by their color. You can insert different PEC groups with different colors. A new PEC group can be defined by simply right clicking on the '''PEC''' item in the Navigation Tree and selecting '''Insert New PEC...''' from the contextual menu. A dialog for setting up the PEC properties opens up. From this dialog you can change the name of the group or its color. Note that PEC object do not have any material properties that can be edited.

Figure 1: MoM3D Module's Navigation Tree and its PEC dialog.

Of the two simulation engines of EM.Cube's MoM3D Module only the Surface MoM solver can handle dielectric objects as dielectric materials cannot be modeled by wireframe structures. Dielectric objects are created under the '''Dielectric''' node in the '''Physical Structure''' section of the Navigation Tree. They are grouped together by their color and material properties. You can insert different dielectric groups with different colors and different permittivity e_r and electric conductivity s. Note that a PEC object is the limiting cases of a lossy dielectric material when σ → ∞.

Figure 2: EM.Cube's material list.

By default, the last PEC group that was defined is active. The current active group is always listed in bold letters in the Navigation Tree. All the new objects are inserted under the current active group. A group can be activated with a right click on its entry in the Navigation Tree and then selecting the '''Active''' item of the contextual menu. You can move one or more selected objects to any desired PEC group. Right click on the highlighted selection and select '''Move To [[Image:/files/images/manuals/emagware/emcube/modules/mom3d/the-metal-structure/moving-objects-between-pec-groups-or-transferring-to-other-modules/larrow_tn.png]] MoM3D [[Image:/files/images/manuals/emagware/emcube/modules/mom3d/the-metal-structure/moving-objects-between-pec-groups-or-transferring-to-other-modules/larrow_tn.png]]''' from the contextual menu. This opens another sub-menu with a list of all the available PEC groups already defined in the PO Module. Select the desired PEC group, and all the selected objects will move to that group. The objects can be selected either in the project workspace, or their names can be selected from the Navigation Tree. In the latter case, make sure that you hold the keyboard's '''Shift Key''' or '''Ctrl Key''' down while selecting a PEC group's name from the contextual menu. In a similar way, you can move one or more objects from a Physical Optics PEC group to EM.CUBE's other modules. In this case, the sub-menus of the''' Move To [[Image:/files/images/manuals/emagware/emcube/modules/mom3d/the-metal-structure/moving-objects-between-pec-groups-or-transferring-to-other-modules/larrow_tn.png]]''' item of the contextual menu will indicate all the EM.CUBE modules that have valid groups for transfer of the select objects.

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The MoM3D Module's method of moments solver assumes an infinite open boundary for your project's structure and uses the free space Green's functions for the background structure. As a result, the extents of the computational domain are infinite in all directions. The mesh generation process in EM.CUBE's MoM3D Module involves three steps:

The regular wireframe mesh of a PEC sphere.

To set the wire-frame mesh properties, click on the [[Image:/files/images/manuals/emagware/emcube/modules/mom3d/mesh-generation/creating-and-viewing-the-mesh/mesh_tool_tn.png]] button of the '''Compute Toolbar''' or select '''Menu [[Image:/files/images/manuals/emagware/emcube/modules/mom3d/the-metal-structure/moving-objects-between-pec-groups-or-transferring-to-other-modules/larrow_tn.png]] Compute [[Image:/files/images/manuals/emagware/emcube/modules/mom3d/the-metal-structure/moving-objects-between-pec-groups-or-transferring-to-other-modules/larrow_tn.png]] Discretization [[Image:/files/images/manuals/emagware/emcube/modules/mom3d/the-metal-structure/moving-objects-between-pec-groups-or-transferring-to-other-modules/larrow_tn.png]] Mesh Settings...'''or right click on the '''3-D Mesh''' item in the '''Discretization''' section or the Navigation Tree and select '''Mesh Settings...''' from the contextual menu. The MoM3D Mesh Settings Dialog opens up. You can change the mesh generation algorithm from the drop-down list labeled '''Mesh Type''' and select one of the two options: '''Regular Wireframe''' or '''Structured Wireframe'''. You can also set the '''Mesh Sampling Rate''', whose default value is 20 Cells/λ₀.By default, surface objects or solids are wire-framed at the mesh cell size. Therefore, each wire segment of the wire-frame mesh contains one cell. Another parameter that can affect the shape of the mesh especially in the case of solid objects is the '''Curvature Angle Tolerance'''. This parameter expressed in degrees determines the apex angle of the triangular cells of the structured mesh. Lower values of the angle tolerance will results in more pointed triangular cells.

Four-port view of the structured wireframe mesh of a PEC sphere.

All the solid objects belonging to the same PEC group are merged together using the Boolean union operation before meshing. If your structure contains attached, interconnected or overlapping solid objects, their internal common faces are removed and only the surface of the external faces is meshed. Similarly, all the surface objects belonging to the same PEC group are merged together before meshing. However, following EM.CUBE's union rules, a solid and a surface object cannot not be "unioned" together. Therefore, their meshes will not connect even if the two objects belong to the same PEC group.

The line object at the top of a PEC sphere and the structure's mesh without and with proximity mesh connection enforced.

EM.CUBE applies the global mesh sampling rate to discretize all the objects in the Project Workspace. However, you can lock the mesh sampling rate of any PEC group to a desired value different than the global rate. To do so, open the property dialog of a PEC group by right clicking on its name in the Navigation Tree and select '''Properties...''' from the contextual menu. At the bottom of the dialog, check the box labeled '''Lock Mesh'''. This will enable the '''Sampling Rate''' box, where you can set a desired value. The default value is equal to the global mesh sampling rate. Keep in mind that objects that belong to different PEC groups are not merged during the mesh generation even if they overlap or are intended to be connected to one another.<br />

Locking the mesh sampling rate of a PEC group.

A Gap is an infinitesimally narrow discontinuity that is placed on the path of the current. In EM.Cube's MoM3D Module, a gap is used to define an excitation source in the form of an ideal voltage source. Gap sources can be placed only on '''Line''' and '''Polyline''' objects. '''If you want to excite a curved wire antennas such as a circular loop or helix with a gap source, first you have to convert the curve object into a polyline using EM.Cube's Polygonize Tool.''' The gap splits the wire into two segment with a an infinitesimally small spacing between them, across which the ideal voltage source is connected. To define a new gap source, follow these steps:

A gap source placed on one side of a polyline representing a polygonized circular loop.

In EM.Cube's MoM3D Module, you can define simple lumped elements in a similar manner as gap sources. In fact, a lumped element is equivalent to an infinitesimally narrow gap that is placed in the path of the current, across which Ohm's law is enforced as a boundary condition. You can define passive RLC lumped elements or active lumped elements containing a voltage gap source. The latter case can be used to excite a wire structure and model a non-ideal voltage source with an internal resistance. Unlike the [[FDTD Module]]'s single-device lumped loads that connect between two adjacent nodes, the MoM3D Module's lumped circuit represent a series-parallel combination of resistor, inductor and capacitor elements. This is shown in the figure below:

The MoM3D Module's lumped element dialog and an active lumped element with a voltage gap in series with an RC circuit placed on a dipole wire.

Ports are used to order and index gap sources for S parameter calculation. They are defined in the '''Observables''' section of the Navigation Tree. Right click on the '''Port Definition''' item of the Navigation Tree and select '''Insert New Port Definition...''' from the contextual menu. The Port Definition Dialog opens up, showing the total number of existing sources in the workspace. By default, as many ports as the total number of sources are created. You can define any number of ports equal to or less than the total number of sources. This includes both gap sources and active lumped elements (which contain gap sources). In the '''Port Association''' section of this dialog, you can go over each one of the sources and associate them with a desired port. Note that you can associate more than one source with same given port. In this case, you will have a coupled port. All the coupled sources are listed as associated with a single port. However, you cannot associate the same source with more than one port. Finally, you can assign '''Port Impedance''' in Ohms. By default, all port impedances are 50&Sigma;. The table titled '''Port Configuration''' lists all the ports and their associated sources and port impedances.

The MoM3D Module's port definition dialog.

If the workspace contains an array of line or polyline objects, the array object will be listed as an eligible object for gap source placement. A gap source will be placed on each element of the array. All the gap sources will have identical direction and offset. However, you can prescribe certain amplitude and/or phase distributions. The available amplitude distributions include '''Uniform''', '''Binomial''' and '''Chebyshev'''. In the last case, you need to set a value for maximum side lobe level ('''SLL''') in dB. You can also define '''Phase Progression''' in degrees along all three principal axes.

The MoM3D Module's gap source dialog and gaps sources defined on an array of dipole wires with binomial weight distribution and 90° phase progression.

A short dipole provides a simple way of exciting a structure in the MoM3D Module. A short dipole source acts like an infinitesimally small ideal current source. To define a short dipole source, follow these steps:

The short dipole source dialog and a short dipole placed in front of a PEC sphere.

The wire-frame structure in the MoM3D Module can be excited by an incident plane wave. In particular, a plane wave source can be used to compute the radar cross section of a metallic target. A plane wave is defined by its propagation vector indicating the direction of incidence and its polarization. EM.CUBE's MoM3D Module provides the following polarization options:

The plane wave dialog and illuminating a metallic sphere with an obliquely incident plane wave source.

Once you have set up your metal structure in EM.CUBE's MoM3D Module, have defined sources and observables and have examined the quality of the structure's wire-frame mesh, you are ready to run a simulation. To open the Run Simulation Dialog, click the '''Run''' [[Image:/files/images/manuals/emagware/emcube/modules/mom3d/running-wire-mom-simulations/running-a-wire-mom-analysis/run_icon.png]] button of the '''Compute Toolbar''' or select Menu [[Image:/files/images/manuals/emagware/emcube/modules/mom3d/the-metal-structure/moving-objects-between-pec-groups-or-transferring-to-other-modules/larrow_tn.png]] Compute [[Image:/files/images/manuals/emagware/emcube/modules/mom3d/the-metal-structure/moving-objects-between-pec-groups-or-transferring-to-other-modules/larrow_tn.png]] Run...or use the keyboard shortcut '''Ctrl+R'''. To start the simulation click the '''Run''' button of this dialog. Once the Wire MoM simulation starts, a new dialog called '''Output Window''' opens up that reports the various stages of Wire MoM simulation, displays the running time and shows the percentage of completion for certain tasks during the Wire MoM simulation process. A prompt announces the completion of the Wire MoM simulation. At this time, EM.CUBE generates a number of output data files that contain all the computed simulation data. These include current distributions, near field data, far field radiation pattern data as well bi-static or mono-static radar cross sections (RCS) if the structure is excited by a plane wave source.

The MoM3D Module's run simulation dialog and output window.

A Wire MoM simulation involves a number of numerical parameters that normally take default values unless you change them. You can access these parameters and change their values by clicking on the '''Settings''' button next to the &quot;Select Engine&quot; drop-down list in the '''Run Dialog'''. This opens up the Wire MoM Engine Settings Dialog. In the '''Solver''' section of the dialog, you can choose the type of linear solver. The current options are '''LU''' and '''Bi-Conjugate Gradient (BiCG)'''. The LU solver is a direct solver and is the default option of the MoM3D Module. The BiCG solver is iterative. Once selected, you have to set a '''Tolerance''' for its convergence. You can also change the maximum number of BiCG iterations by setting a new value for '''Max. No. of Solver Iterations / System Size'''. The Wire MoM simulator is based on Pocklington's integral equation method. In this method, the wires are assumed to have a very small radius. The basis functions are placed on the axis of the &quot;wire cylinder&quot;, while the Galerkin testing is carried out on its surface to avoid the singularity of the Green's functions. In the &quot;Source Singularity&quot; section of the dialog, you can specify the '''Wire Radius''' . EM.CUBE's MoM3D Module assumes an identical wire radius for all wires and wireframe structures. This radius is expressed in free space wavelengths and its default value is 0.001&lambda;₀. The value of the wire radius has a direct influence on the wire's computed reactance.

The wire MoM engine settings dialog.

At the end of a MoM3D simulation, EM.CUBE's Wire MoM engine generates a number of output data files that contain all the computed simulation data. The main output data are the current distributions and far fields. You can easily examine the 3-D color-coded intensity plots of current distributions in the Project Workspace. Current distributions are visualized on all the wires and the magnitude and phase of the electric currents are plotted for all the PEC objects. In order to view these currents, you must first define current sensors before running the Wire MoM simulation. To do this, right click on the '''Current Distributions''' item in the '''Observables''' section of the Navigation Tree and select '''Insert New Observable...'''. The Current Distribution Dialog opens up. Accept the default settings and close the dialog. A new current distribution node is added to the Navigation Tree. Unlike the [[Planar Module]], in the MoM3D Module you can define only one current distribution node in the Navigation Tree, which covers all the PEC object in the Project Workspace. After a Wire MoM simulation is completed, new plots are added under the current distribution node of the Navigation Tree. Separate plots are produced for the magnitude and phase of the linear wire currents. The magnitude maps are plotted on a normalized scale with the minimum and maximum values displayed in the legend box. The phase maps are plotted in radians between -&pi; and &pi;.

The output plot settings dialog, and the current distribution of the monopole-plate structure with a user defined upper limit.

If the project structure is excited by gap sources, and one or more ports have been defined, the Wire MoM engine calculates the scattering (S) parameters of the selected ports, all based on the port impedances specified in the project's &quot;Port Definition&quot;. If more than one port has been defined in the project, the scattering matrix of the multiport network is calculated. The S parameters are written into output ASCII data files. Since these data are complex, they are stored as '''.CPX''' files. Every file begins with a header starting with &quot;#&quot;. The admittance (Y) and impedance (Z) parameters are also calculated and saved in complex data files with '''.CPX''' file extensions. The voltage standing wave ratio of the structure at the first port is also computed and saved to a real data '''.DAT''' file.

The Smith chart.

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EM.CUBE allows you to visualize the near fields at a specific field sensor plane. Calculation of near fields is a post-processing process and may take a considerable amount of time depending on the resolution that you specify. To define a new Field Sensor, follow these steps:

Electric and magnetic field plots of the circular loop antenna.

Unlike the FDTD method, in the MoM3D Module you do not need a far field box to perform near-to-far-field transformations. Nonetheless, you still need to define a far field observable if you want to plot radiation patterns. A far field can be defined by right clicking on the '''Far Fields''' item in the '''Observables''' section of the Navigation Tree and selecting '''Insert New Radiation Pattern...''' from the contextual menu. The Radiation Pattern dialog opens up. You can accept most of the default settings in this dialog. The Output Settings section allows you to change the '''Angle Increment''' in the degrees, which indeed sets the resolution of far field calculations. The default value is 5 degrees. After closing the radiation pattern dialog, a far field entry immediately appears with its given name under the '''Far Fields''' item of the Navigation Tree and can be right clicked for further editing.

3-D radiation pattern of the circular loop antenna: (Left) Theta component, (Center) Phi components, and (Right) total far field.

In view of far field characteristics, EM.CUBE can handle antenna arrays in two different ways. The first approach is full-wave and requires building an array of radiating elements using the '''Array Tool''' and feeding individual array elements using some type of excitation. This method is very accurate and takes into account all the inter-element coupling effects. At the end of the Wire MoM simulation of the array structure, you can plot the radiation patterns and other far field characteristics of the antenna array just like any other wire-frame structure. The second approach is based on the &quot;Array Factor&quot; concept and ignores any inter-element coupling effects. In this approach, you can regard the structure in the project workspace as a single radiating element. A specified array factor can be calculated and multiplied by the element pattern to estimate the radiation pattern of the overall radiating array. To define an array factor, open the '''Radiation Pattern Dialog''' of the project. In the section titled '''Impose Array Factor''', you will see a default value of 1 for the '''Number of Elements''' along the three X, Y and Z directions. This implies a single radiator, which is your structure in the project workspace. There are also default zero values for the '''Element Spacing''' along the X, Y and Z directions. You should change both the number of elements and element spacing in the X, Y or Z directions to define any desired finite array lattice. For example, you can define a linear array by setting the number of elements to 1 in two directions and entering a larger value for the number of elements along the third direction.

Radiation pattern of a 4-element dipole array: (Left) computed using array factor and (Right) computed by simulating an array object.

When the wire-frame structure is excited by a plane wave source, the calculated far field data indeed represent the scattered fields. EM.CUBE calculates the radar cross section (RCS) of a target, which is defined in the following manner:

The RCS of the wire-plate structure: (Left) &sigma;_&theta;, (Center) &sigma;_&phi; and (Right) total RCS..

Similar to the current distribution and field sensor plots, EM.CUBE's 3-D radiation pattern plots are interactive. When you move the mouse over a pattern plot, tiny dots appear on its surface. These dots correspond to the theta-phi angle pairs on the surface of the unit sphere where the far field data have been calculated. Upon mouse-over, you can highlight one of these points. A small tooltip appears on the plot that shows the normalized far field value in that direction.

Just like current distribution and field sensor plots, each individual 3-D radiation pattern plots has an '''Output Settings Dialog''', from which you can further customize the plot's scale (linear vs. dB), lower and upper limits and color map type.

At the end of a Wire MoM simulation, the radiation pattern data E_&theta;, E_&phi;, and E_tot in the three principal XY, YZ and ZX planes as well as an additional user defined phi plane cut are available for plotting on 2-D graphs. There are a total of eight 2D pattern graphs in the data manager: 4 polar graphs and 4 Cartesian graphs of the same pattern data. To open data manager, click the '''Data Manager''' [[Image:/files/images/manuals/emagware/emcube/modules/mom3d/visualizing-simulation-data/scattering-parameters-and-port-characteristics/data_manager_icon.png]] button of the '''Compute Toolbar''' or select '''Compute [[Image:/files/images/manuals/emagware/emcube/modules/mom3d/the-metal-structure/moving-objects-between-pec-groups-or-transferring-to-other-modules/larrow_tn.png]]Data Manager''' from the menu bar or right click on the '''Data Manager''' item of the Navigation Tree and select Open Data Manager... from the contextual menu or use the keyboard shortcut '''Ctrl+D'''. In the Data manager Dialog, you will see a list of all the data files available for plotting. These include the four polar pattern data files with a '''.ANG''' file extension and the four Cartesian pattern data file with a '''.DAT''' file extension. Select any data file by clicking and highlighting its '''ID''' in the table and then click the '''Plot''' button to plot the graph.

The data manager dialog showing a list of 2-D polar and Cartesian radiation pattern graphs.

You can run EM.CUBE's MoM3D simulation engine in the sweep mode, whereby a parameter like frequency, plane wave angles of incidence or a user defined variable is varied over a specified range at predetermined samples. The output data are saved into data file for visualization and plotting. EM.CUBE's MoM3D Module currently offers three types of sweep:

In a parametric sweep, one or more user defined variables are varied at the same time over their specified ranges. This creates a parametric space with the total number of samples equal to the product of the number of samples for each variable. The user defined variables are defined using EM.CUBE's '''Variables Dialog'''. For a description of EM.CUBE variables, please refer to the CUBECAD manual or the &quot;Parametric Sweep&quot; sections of the FDTD or [[Planar Module]] manuals.

At the end of a frequency, angular or parametric sweep simulation in EM.CUBE's MoM3D Module, the output data are saved for visualization and plotting. In particular, if you have defined current distribution, field sensor or far field observables in your project, multiple 3-D plots as many as the total number of sweep samples are added to the Navigation Tree. In a single simulation run, a total of 7 current distribution plots, 14 field sensor plot and 3 radiation pattern plots or 3 RCS plots are generated under every observable node defined in the navigation tree. However, after a sweep simulation, only one plot is saved for each sweep sample. This is done to keep the resulting plots manageable. Thus, only the magnitude of the total wire currents '''|J_L|''' and the total radiation pattern or total RCS are saved for each sweep sample. In the case of a field sensor observable, you have the choice to save either the total E-field magnitude plot or the total H-field magnitude plot. To change this, open the '''Field Sensor Dialog''' by right clicking on a field sensor's name in the Navigation Tree and selecting '''Properties...''' from the contextual menu. In the '''Field Display - Multiple Plots''' section of this dialog, select one of the radio sensors labeled '''E-Field''' or '''H-Field''' From this dialog, you can also choose the type of 3-D field plot for animation. The options are '''Confetti''' or '''Cone'''.