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== Examining the FDTD Mesh ==
[[EM.Tempo]] generates a “staircase” Yee mesh of your physical structure. To be able to capture the details of your dipole's very fine cylindrical arms, the mesh should have adequate resolution. [[EM.Tempo]]’s default “Adaptive” FDTD mesh generator exactly does that. To view the mesh, click the <b>Show/Generate Mesh</b> [[Image:fdtd_meshshow.png]] button of the Simulate Toolbar or alternatively use the keyboard shortcut {{key|Ctrl+M}}. The resolution of the mesh is determined by its '''Mesh Density''' expressed in effective wavelength. EM.Tempo's default mesh density of is 20 cells/&lambda;<sub>eff</sub>. However, the wizard automatically set sets the mesh density to 50 cells/&lambda;<sub>eff</sub> for this particular structure. Open the FDTD Mesh Settings dialog by clicking the <b>Mesh Settings</b> [[Image:fdtd_meshsettings.png]] button of Simulate Toolbar or using the keyboard shortcut {{key|Ctrl+G}}. The FDTD Mesh Settings dialog offers a large number of parameters that can be used to fine-tune the Yee mesh to better approximate and represent your physical structure.
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Before you run your first FDTD simulation in [[EM.Tempo]], let’s take a closer look at the FDTD simulation engine’s settings. Click the {{key|Settings}} button next to the “Select Engine” drop-down list to bring up the FDTD Engine Settings dialog. The convergence section ("Termination Criterion") of this dialog offers three criteria for terminating the FDTD time marching scheme. The first one is a <b>Power Threshold</b>, which normally has a default value of -30dB. The second one is a maximum number of steps (<b>Maximum Number of No. Time Steps</b>), which normally has a default value of 10,000. The third option is labeled “Both”, which means that both of the above termination criteria will be considered until one of them is met. For this particular structure, the wizard set the power threshold equal to -50dB 40dB and the maximum number of time steps to 20,000.
{{Note|For highly resonant structures, it is recommended that you establish a much more demanding convergence criterion with a lower power threshold value and a larger number of time steps.}}
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You can see from the legend box of the plot that the directivity of your dipole is computed to be D0 = 1.624632.
== Plotting the 2D Radiation Pattern Graphs ==
[[EM.Tempo]]'s data manager also contains a list of 2D radiation pattern graphs of both Cartesian and polar types. Click the <b>Data Manager</b> [[Image:fdtd_datamanagerb.png]] button of Simulate Toolbar and plot the two files “FF_1_PATTERN_Cart_YZ.DAT” and “FF_1_PATTERN_Polar_YZ.ANG”. Note that you can make multiple file selections using '''Shift''' and '''Ctrl''' keys. Click the {{key|Plot}} button of the Data Manager dialog to plot both files.
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