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 Conditionsâ¦</b> 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 <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.
==1.5 Source Definition==
==Source Definition==
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[[Image:fdtd_lec1_11_lumpedsource.png|right]] A dipole antenna can be excited using a lumped source, which is one of the simplest source types in [[FDTD Module]]. A lumped source is a voltage source in series with an internal resistance that is placed between two adjacent nodes of the FDTD mesh. To define a lumped source, right-click on the <b>Lumped Source</b> item in the âSourcesâ section of the Navigation Tree, and select <b>Insert New Sourceâ¦</b> The Lumped Source Dialog opens up.
[[Image:fdtd_lec1_11_lumpedsource.png|400px|right]] A dipole antenna can be excited using a lumped source, which is one of the simplest source types in [[FDTD Module]]. A lumped source is a voltage source in series with an internal resistance that is placed between two adjacent nodes of the FDTD mesh. To define a lumped source, right-click on the <b>Lumped Source</b> item in the âSourcesâ section of the Navigation Tree, and select <b>Insert New Sourceâ¦</b> The Lumped Source Dialog opens up.
[[Image:fdtd_lec1_12_lumpedsourcefig.png|350px|left]] A lumped source can only be placed on a line object. Additionally, the line must be parallel to one of the principal axes. The dropdown list labeled <i>Line Object</i> displays all the eligible lines in the project workspace. In this project, there is only one object, which is selected by default. A new lumped source is placed at the center of the host line object by default. The location of the source can be changed via the <i>Offset</i> parameter of the dialog. We will leave this at 75 for this tutorial, as we want to test a center-fed dipole. You can also change the direction of the lumped source.
Your lumped source will have an <b>Amplitude</b> of 1V and a zero <b>Phase</b>. This means that the voltage source will excite the dipole with a modulated Gaussian pulse waveform centered at 1GHz with a frequency bandwidth of 1GHz, where the envelope of the signal reaches a maximum voltage of 1V. You will see the lumped source in the middle of the dipole, represented by an arrow pointing in the +Z direction.
Your lumped source will have an <b>Amplitude</b> of 1V and a zero <b>Phase</b>. This means that the voltage source will excite the dipole with a modulated Gaussian pulse waveform centered at 1GHz with a frequency bandwidth of 1GHz, where the envelope of the signal reaches a maximum voltage of 1V. You will see the lumped source in the middle of the dipole, represented by an arrow pointing in the +Z direction.
==1.6 Grid Settings & Mesh Generation==