Changes

[[Image:fdtd_lec1_10_domainboundary.png|right]] As soon as you draw your first object in [[FDTD Module]]’s project workspace, a blue wireframe box appears which completely encloses your object. This is [[FDTD Module]]’s computational domain box. Since FDTD is a finite-domain numerical technique, it requires a computational domain of finite extents. By default, the domain box is placed a quarter free space wavelength from the largest bounding box of your physical structure. You can confirm this by opening the Domain Settings Dialog. Click the <b>Domain Settings</b> [[Image:fdtd_domainsettingsfdtd_domainsettings2.png]] button of Simulate Toolbar (or select the menu item <b>Compute &rarr; Computational Domain &rarr; Domain Settings…</b> or use the keyboard shortcut <b>Ctrl+A</b>) to bring up the domain dialog box. For the default domain type, the domain size is specified in terms of offsets along the ±X, ±Y, and ±Z directions, i.e., the distances between the largest bounding box of the geometry and all the six domain boundaries. The offsets are expressed in free space wavelengths calculated at the highest frequency of the project, which is fmax = f0 + &Delta;f/2, where f0 is the center frequency of the project and &Delta;f is the bandwidth.

The boundary Conditions at the six faces of the computational domain can be set by selecting the menu item <b>Simulate &rarr Computational Domain &rarr Boundary Conditions…</b> or by right clicking on the “Boundary Conditions” item in the “Computational Domain” section of the Navigation Tree. By default, EM.Cube’s [[FDTD Module]] assumes an open-boundary physical structure. All the six boundaries default to <b>PML</b>, or Perfectly Matched Layer, which you are going to maintain for this tutorial lesson. But the dropdown lists allow you to also choose <b>PEC</b>, or a Perfect Electric Conducting boundary, or <b>PMC</b>, a Perfect Magnetic Conducting boundary.  [[Image:fdtd_lec1_10_domainboundary.png|center]]