[[Image:Info_icon.png|40px]] Click here to learn more about '''[[Perfectly_Matched_Layer_Termination#Advanced_CMPL_Setup | Advanced CPML Setup]]'''.
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== Advanced CMPL Setup in EM.Tempo ==
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[[Image:fdtd_manual-11.png|thumb|400px|The boundary ABC cells placed outside the visible domain box.]]
[[Image:FDTD15.png|thumb|400px|CPML Settings dialog.]]
[[EM.Tempo]] provides Perfectly Matched Layers (PML) as absorbing boundary conditions. Usually two or more ABC layers must be placed at the boundaries of the physical structure to maximize wave absorption. The boundary ABC cells in [[EM.Tempo]]'s project workspace are transparent to the user. But, in effect, multiple rows of ABC cells are placed on the exterior side of each face of the visible domain box.
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You can set the number of CPML layers as well as their order. This is done through the CPML Settings Dialog, which can be accessed by right clicking on the '''CPML''' item in the '''Computational Domain''' section of the navigation tree and selecting '''CPML Settings...''' from the contextual menu. By default, four CPML layers of the third order are placed outside the FDTD problem domain. It is recommended that you always try a four-layer CPML first to assess the computational efficiency. The number of CPML layers may be increased only if a very low reflection is required (<-40dB).
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{{Note|[[EM.Tempo]]'s default quarter wavelength offset for the domain box is a very conservative choice and can be reduced further in many cases. A offset equal to eight free-space grid cells beyond the largest bounding box usually give a more compact, but still valid, domain box.}}
===Modeling Planar Structures of Infinite Extents===