Plane wave sources are used to inject uniform electromagnetic energy from a line or surface within the simulation region. In two-dimensional simulations, the plane wave source injects along an arbitrary straight or curved line, while in three-dimensional simulations the plane wave source injects along a plane or curved surface. The injection direction can be either aligned with one of the axis or determined by a k-vector.
Using plane wave source as Total-Field Scattered-Field Source
The plane wave source can be also used as a Total-Field Scattered-Field (TFSF) source by defining the injection region as a closed-loop or closed surface for 2D or 3D simulations respectively. Total-field scattered-field source configuration separates the computation region into two distinct regions – one contains the total field (i.e. the sum of the incident field and the scattered field), while the second region contains only the scattered field. This source type is particularly useful to study the scattering behavior of objects, as the scattered field can be isolated from the incident field.
| [[Notes:]] For correct results when using the plane wave as a TF/SF source, ensure the same material is assigned on both sides of the closed curve or closed surface. |
Plane wave source behavior
The following examples show how plane wave source injects fields from a curved line into a 2D simulation region. We compare the behavior for two cases - one with opened curve and one with a closed curve to show how the plane wave source can be used as a Total-Field Scattered-Field source. We analyze both sources in a vacuum to show the injected fields without any interaction with the surrounding environment and then we add a strong scatterer to the simulation region to demonstrate how the scattered fields behave with respect to the source area and the rest of the simulation region. To reproduce the results, download the associated files and open them in In DGTD and FEEM.
The results depicted in the figures below show that the source injection curve and injection direction determine where the plane wave enters the simulation region. For the closed source, the source line separates the total fields (injected + scattered fields) from the scattered fields. If the source remains opened and the curve is not closed the scattered fields do not get separated out from the total fields.
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Injecting from an opened curved line |
Injecting from a closed curved line (TFSF configuration) |
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 Ex field component |
 Ex field component |
 Adding a strong scatterer (circle in the center) to the simulation region. The surronding material is vacuum. |
 Adding a strong scatterer (circle in the center) to the simulation region. The surronding material is vacuum. |
 Ex field component |
 Ex field component |
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Tip: Plane wave source in total-field scattered-field configuration The plane wave source above can be also used as Total-field scattered-field source by defining the injection region as a closed-loop or closed surface for 2D or 3D simulations respectively. Total-field scattered-field source configuration separates the computation region into two distinct regions – one contains the total field (i.e. the sum of the incident field and the scattered field), while the second region contains only the scattered field. This source type is particularly useful to study the scattering behavior of objects, as the scattered field can be isolated from the incident field. |
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Note: Using multiple sources When using multiple sources in a simulation, extra care must be taken to ensure you understand how the results are normalized. For example, if we use two orthogonal sources that each have an amplitude of 1 and inject in z-direction, the monitor shows that the amplitude of both Ex and Ey are 1. This implies that |E| = sqrt(2). A transmission calculated in front of the sources would return 2 because the normalization is executed against the sum of the source power from the first source. Additionally, if using multiple sources, they should have all identical frequency settings. |
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Notes: Injecting light alongside PML It is recommended to avoid injecting fields into the simulation region directly at the PML boundary that is aligned with the injection direction. The interaction of the injected fields and PML will introduce spurious effects that might affect the accuracy. |
General tab
- AMPLITUDE: The amplitude of the source.
- PHASE: The phase of the point source, measured in units of degrees. Only useful for setting relative phase delays between multiple radiation sources.
- DIRECTION: This field specifies the direction in which the radiation propagates. FORWARD corresponds to propagation in the positive direction, while BACKWARD corresponds to propagation in the negative direction.
- DIRECTION DEFINITION: Specifies whether to define the injection direction using a reference axis or k-vector components
- INJECTION AXIS: Sets the axis along which the radiation propagates.
- ANGLE THETA: The angle of propagation, measured in degrees, with respect to the injection axis defined above.
- ANGLE PHI: The angle of propagation, in degrees, rotated about the injection axis in a right-hand context.
- K-VECTOR
- KX: k-vector component in x axis direction
- KY: k-vector component in y axis direction
- KZ: k-vector component in z axis direction
- POLARIZATION ANGLE: The polarization angle defines the orientation of the injected electric field, and is measured with respect to the plane formed by the direction of propagation and the normal to the injection plane. A polarization angle of zero degrees defines P-polarized radiation, regardless of direction of propagation while a polarization angle of 90 degrees defines S-polarized radiation.
Geometry tab
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Note: A list of domains will be available under the SIMULATION REGION object once the simulation region is partitioned. A list of solids (primitives) is available under the GEOMETRY Container Group. |
Volume, surface, line, and point in 3D and 2D:
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Volume |
Surface |
Point |
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3D |
Volume |
Surface or Line |
Point |
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2D |
Surface |
Line |
Point |
Surface Type
- DOMAIN:EXTERIOR : Select the target domain. The reference geometry is the common surface(s) shared by the uttermost surface(s) of the selected domain and the simulation region. The selected domain has to have at least a surface that is shared with one of the simulation region surfaces.
- DOMAIN:DOMAIN : Select the target domains. The reference geometry is the common surface(s) shared by the two selected domains.
- DOMAIN : Select the target domain. The reference geometry is the surfaces of the selected domain.
- SOLID : Select the target solid. The reference geometry is the surfaces that enclose the selected volume if the solid is a 3D shape, or the surface if the solid is a 2D plane.
- SIMULATION REGION : Select one or more simulation region boundaries. The reference geometry is the selected boundaries.
- SOLID:SIMULATION REGION : Select one or more simulation region boundaries and the target solid. The reference geometry is the common surface(s) shared by the simulation region and the target solid.
- MATERIAL:MATERIAL : Select the target materials. The reference geometry is the surface(s) that is shared by the two selected materials. This is only available in some boundary conditions.
- SURFACE : Type the identifier of the partition surface. If the target partition surface is SURFACE 3, type 3. If the target partition surfaces are SURFACE 3 and SURFACE 5, enter 3,5.
Frequency/Wavelength tab
This tab can be accessed through the individual source properties. Note that the plots on the right-hand side of the window update as the parameters are updated, so that you can easily observe the wavelength (top figure), frequency (middle figure), and temporal (bottom figure) content of the source settings.
At the top-left of the tab, it is possible to chose to either SET FREQUENCY / WAVELENGTH or SET TIME-DOMAIN. In most simulations, the 'SET FREQUENCY / WAVELENGTH ' option is recommended.
Results returned
- GRID: Provides information about the area, domain ID, and refractive index for each element in the simulation grid