Before you begin to set up the geometry of your project, letâs quickly ensure that the project units are set up correctly. First, open up the Units Dialog box by selecting the Units button of the Simulate Toolbar (or using the keyboard shortcut Ctrl+U). Make sure the length units are Millimeters, and select OK to continue. Similarly, for frequency and bandwidth, select the Frequency button of the Simulate Toolbar (or use the keyboard shortcut Ctrl+F) to open the Frequency Dialog box. Make sure both the frequency and bandwidth are 1GHz, and select OK to continue.
[[Image:Fdtd_lec1_2a_unitsfrequency.png|350px450px|center]]
==1.2 FDTD Module Navigation==
==1.3 Creating a Wire Object==
Line).
Select the Line Tool from the Object Toolbar (or use the keyboard shortcut F3, or the menu Object ï Curve ï Line).Â
[[Image:fdtd_lec1_7_toolbarline.png|700px|center]]
[Image:fdtd_lec1_8_lineproprerties.png|400px]]
Since the center frequency of the project is 1GHz, the operating wavelength is:
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For your resonant dipole to be half-wave, it can be approximated at 150mm.
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Once your drawing is complete, you can zoom to fit your stucture into the screen using the keyboard shortcut Ctrl+E or by clicking the Zoom Extents button of View Toolbar. After you have rotated or panned the view, you can always restore EM.Cubeâs standard perspective view using the keyboardâs Home Key or by clicking the Perspective View button of View Toolbar.
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[[Image:fdtd_lec1_9_nevigationtree.png|350x|right]] In EM.Cubeâs [[FDTD Module]], objects are grouped together and organized by material under the âPhysical Structureâ node of the Naviation Tree. Since you selected no material for your line object, the first drawn object is automatically assigned a PEC_1 material group. The default perfect electric conductor (PEC) group is set as the active material. When a material group is set as active, its name appears in bold letters, and all subsequently drawn objects will be placed under that material node. Any material group can be set as the active material by right-clicking on its name in the Navigation Tree and selecting Activate from the contextual menu.
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==1.4 omputational Domain & Boundary Conditions==
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As soon as you draw your first object in [[FDTD Module]]âs project workspace, a blue wireframe box appears which completely encloses your object. This is [[FDTD Module]]âs 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 Domain Settings button of Simulate Toolbar (or select the menu item Compute ï Computational Domain ï Domain Settings⦠or use the keyboard shortcut Ctrl+A) 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 + ïf/2, where f0 is the center frequency of the project and ïf is the bandwidth.
The boundary Conditions at the six faces of the computational domain can be set by selecting the menu item Simulate ï Computational Domain ï Boundary Conditions⦠or by right clicking on the âBoundary Conditionsâ item in the âComputational Domainâ section of the Navigation Tree. By default, EM.Cubeâs [[FDTD Module]] assumes an open-boundary physical structure. All the six boundaries default to PML, or Perfectly Matched Layer, which you are going to maintain for this tutorial lesson. But the dropdown lists allow you to also choose PEC, or a Perfect Electric Conducting boundary, or PMC, a Perfect Magnetic Conducting boundary.
[[Image:fdtd_lec1_9_nevigationtree.png|500px]]
[[Image:fdtd_lec1_10_domainboundary.png|500px]]
[[Image:fdtd_lec1_11_lumpedsource.png|500px]]