<tr>
</table>
[[Image:Tutorial_icon.png|30px]] '''[[EM.Cube#EM.Illumina_Tutorial_Lessons Illumina_Documentation | EM.Illumina Tutorial Gateway]]'''
[[Image:Back_icon.png|30px]] '''[[EM.Cube | Back to EM.Cube Main Page]]'''
|-
| style="width:30px;" | [[File:pec_group_icon.png]]
| style="width:150px250px;" | [[Glossary of EM.Cube's Materials , Sources, Devices & Other Physical Object Types#Perfect Electric Conductor (PEC) |Perfect Electric Conductor (PEC) Surface]]
| style="width:300px;" | Modeling perfect metal surfaces
| style="width:250px;" | Solid and surface objects
|-
| style="width:30px;" | [[File:pmc_group_icon.png]]
| style="width:150px250px;" | [[Glossary of EM.Cube's Materials , Sources, Devices & Other Physical Object Types#Perfect Magnetic Conductor (PMC) |Perfect Magnetic Conductor (PMC) Surface]]
| style="width:300px;" | Modeling perfect magnetic surfaces
| style="width:250px;" | Solid and surface objects
|-
| style="width:30px;" | [[File:voxel_group_icon.png]]
| style="width:150px250px;" | [[Glossary of EM.Cube's Materials , Sources, Devices & Other Physical Object Types#Impedance Surface |Impedance /Dielectric Surface]]
| style="width:300px;" | Modeling impedance surfaces as an equivalent to the surface of dielectric objects
| style="width:250px;" | Solid and surface objects
|-
| style="width:30px;" | [[File:Virt_group_icon.png]]
| style="width:250px;" | [[Glossary of EM.Cube's Materials, Sources, Devices & Other Physical Object Types#Virtual_Object_Group | Virtual Object]]
| style="width:300px;" | Used for representing non-physical items
| style="width:250px;" | All types of objects
|}
Click on each category to learn more details about it in the [[Glossary of EM.Cube's Materials , Sources, Devices & Other Physical Object Types]].
[[EM.Illumina]] can only handle surface and solid CAD objects. Only the outer surface of solid objects is considered in the PO simulation. No line or curve objects are allowed in the project workspace; or else, they will be ignored during the PO simulation.
=== Organizing Geometric Objects by Surface Type ===
You can define several PEC, PMC or impedance surface groups with different colors and impedance values. All the objects created and drawn under a group share the same color and other properties. Once a new surface node has been created on the navigation tree, it becomes the "Active" surface group of the project workspace, which is always listed in bold letters. When you draw a new CAD object such as a Box or a Sphere, it is inserted under the currently active surface type. There is only one surface group that is active at any time. Any surface type can be made active by right clicking on its name in the navigation tree and selecting the '''Activate''' item of the contextual menu. It is recommended that you first create surface groups, and then draw new objects under the active surface group. However, if you start a new [[EM.Illumina]] project from scratch, and start drawing a new object without having previously defined any surface groups, a new default PEC surface group is created and added to the navigation tree to hold your new CAD object.
[[Image:Info_icon.png|40px30px]] Click here to learn more about '''[[Defining_Materials_in_EM.CubeBuilding Geometrical Constructions in CubeCAD#Moving_Objects_among_Material_Groups Transferring Objects Among Different Groups or Modules | Moving Objects among Surface Different Groups]]'''.
{{Note|In [[EM.Cube]], you can import external CAD models (such as STEP, IGES, STL models, etc.) only to [[CubeCAD]]. From [[CubeCAD]], you can then move the imported objects to [[EM.Illumina]].}}
<table>
|-
| style="width:30px;" | [[File:hertz_src_icon.png]]
| [[Glossary of EM.Cube's Excitation Materials, Sources, Devices & Other Physical Object Types#Hertzian Short Dipole Source |Hertzian Short Dipole Source]]
| style="width:300px;" | Almost omni-directional physical radiator
| style="width:300px;" | None, stand-alone source
|-
| style="width:30px;" | [[File:plane_wave_icon.png]]
| [[Glossary of EM.Cube's Excitation Materials, Sources, Devices & Other Physical Object Types#Plane Wave |Plane Wave Source]]
| style="width:300px;" | Used for modeling scattering
| style="width:300px;" | None, stand-alone source
|-
| style="width:30px;" | [[File:huyg_src_icon.png]]
| [[Glossary of EM.Cube's Excitation Materials, Sources, Devices & Other Physical Object Types#Huygens Source |Huygens Source]]| style="width:300px;" | Used for modeling equivalent sourced sources imported from other [[EM.Cube]] modules
| style="width:300px;" | Imported from a Huygens surface data file
|}
Click on each category to learn more details about it in the [[Glossary of EM.Cube's Excitation Materials, Sources, Devices & Other Physical Object Types]].
A short Hertzian dipole is the simplest way of exciting a structure in [[EM.Illumina]]. A short dipole source acts like an infinitesimally small ideal current source. The total radiated power by your dipole source is calculated and displayed in Watts in its property dialog. Your physical structure in [[EM.Illumina]] can also be excited by an incident plane wave. In particular, you need a plane wave source to compute the radar cross section of a target. The direction of incidence is defined by the θ and φ angles of the unit propagation vector in the spherical coordinate system. The default values of the incidence angles are θ = 180° and φ = 0° corresponding to a normally incident plane wave propagating along the -Z direction with a +X-polarized E-vector. Huygens sources are virtual equivalent sources that capture the radiated electric and magnetic fields from another structure that was previously analyzed in another [[EM.Cube]] computational module.
| style="width:30px;" | [[File:currdistr_icon.png]]
| style="width:150px;" | Current Distribution Maps
| style="width:150px;" | [[Glossary of EM.Cube's Simulation Observables& Graph Types#Current Distribution |Current Distribution]]
| style="width:300px;" | Computing electric surface current distribution on PEC and impedance surfaces and magnetic surface current distribution on PMC and impedance surfaces
| style="width:250px;" | None
| style="width:30px;" | [[File:fieldsensor_icon.png]]
| style="width:150px;" | Near-Field Distribution Maps
| style="width:150px;" | [[Glossary of EM.Cube's Simulation Observables& Graph Types#Near-Field Sensor |Near-Field Sensor]]
| style="width:300px;" | Computing electric and magnetic field components on a specified plane in the frequency domain
| style="width:250px;" | None
| style="width:30px;" | [[File:farfield_icon.png]]
| style="width:150px;" | Far-Field Radiation Characteristics
| style="width:150px;" | [[Glossary of EM.Cube's Simulation Observables& Graph Types#Far-Field Radiation Pattern |Far-Field Radiation Pattern]]
| style="width:300px;" | Computing the radiation pattern and additional radiation characteristics such as directivity, axial ratio, side lobe levels, etc.
| style="width:250px;" | None
| style="width:30px;" | [[File:rcs_icon.png]]
| style="width:150px;" | Far-Field Scattering Characteristics
| style="width:150px;" | [[Glossary of EM.Cube's Simulation Observables& Graph Types#Radar Cross Section (RCS) |Radar Cross Section (RCS)]]
| style="width:300px;" | Computing the bistatic and monostatic RCS of a target
| style="width:250px;" | Requires a plane wave source
| style="width:30px;" | [[File:huyg_surf_icon.png]]
| style="width:150px;" | Equivalent electric and magnetic surface current data
| style="width:150px;" | [[Glossary of EM.Cube's Simulation Observables& Graph Types#Huygens Surface |Huygens Surface]]
| style="width:300px;" | Collecting tangential field data on a box to be used later as a Huygens source in other [[EM.Cube]] modules
| style="width:250px;" | None
|}
Click on each category to learn more details about it in the [[Glossary of EM.Cube's Simulation Observables& Graph Types]].
Current distributions are visualized on the surface of PO mesh cells, and the magnitude and phase of the electric and magnetic surface currents are plotted for all the objects. A single current distribution node in the navigation tree holds the current distribution data for all the objects in the project workspace. Since the currents are plotted on the surface of the individual mesh cells, some parts of the plots may be blocked by and hidden inside smooth and curved objects. To be able to view those parts, you may have to freeze the obstructing objects or switch to the mesh view mode.
== Discretizing the Physical Structure in EM.Illumina ==
[[EM.Illumina]] uses a triangular surface mesh to discretize the structure of your project workspace. The mesh generating algorithm tries to generate regularized triangular cells with almost equal surface areas across the entire structure. You can control the cell size using the "Mesh Density" parameter. By default, the mesh density is expressed in terms of the free-space wavelength. The default mesh density is 10 cells per wavelength. In the Physical Optics method, the electric and magnetic surface currents, '''J''' and '''M''', are assumed to be constant on the surface of each triangular cell. On flat surfaces, the unit normal vectors to all the cells are identical. Incident plane waves or other relatively uniform source fields induce uniform PO currents on all these cells. Therefore, a high resolution mesh may not be necessary on flat surface or faces. Accurate discretization of curved objects like spheres or ellipsoids, however, requires a high mesh density.
<table>
</table>
Since [[EM.Illumina]] is a surface simulator, only the exterior surface of solid CAD objects is discretized, as the interior volume is not taken into account in a PO analysis. By contrast, surface CAD objects are assumed to be double-sided. In other words, the default PO mesh of a surface object consists of coinciding double cells, one representing the upper or positive side and the other representing the lower or negative side. This may lead to a very large number of cells. [[EM.Illumina]]'s mesh generator has settings that allow you to treat all mesh cells as double-sided or all single-sided. You can do that in the Mesh Settings dialog by checking the boxes labeled '''All Double-Sided Cells''' and '''All Single-Sided Cells'''. This is useful when your project workspace contains well-organized and well-oriented surface CAD objects only. In the single-sided case, it is very important that all the normals to the cells point towards the source. Otherwise, your surfaces fall in the shadow region, and no currents will be computed on them. By checking the box labeled '''Reverse Normal''', you instruct [[EM.Illumina]] to reverse the direction of the normal vectors globally at the surface of all the cells. [[Image:Info_icon.png|30px]] Click here to learn more about '''[[Preparing_Physical_Structures_for_Electromagnetic_Simulation#Working_with_EM.Cube.27s_Mesh_Generators | Working with Mesh Generator]]'''.
[[Image:Info_icon.png|40px30px]] Click here to learn more about [[EM.Illumina]]'s '''[[Mesh_Generation_Schemes_in_EM.CubePreparing_Physical_Structures_for_Electromagnetic_Simulation#The_Triangular_Surface_Mesh_Generator | EM.Illumina's Triangular Surface Mesh Generator ]]'''.
<table>
[[Image:Top_icon.png|30px]] '''[[EM.Illumina#Product_Overview | Back to the Top of the Page]]'''
[[Image:Tutorial_icon.png|30px]] '''[[EM.Cube#EM.Illumina_Tutorial_Lessons Illumina_Documentation | EM.Illumina Tutorial Gateway]]'''
[[Image:Back_icon.png|30px]] '''[[EM.Cube | Back to EM.Cube Main Page]]'''