{{projectinfo|Tutorial| Designing a Yagi-Uda Dipole Array|Libera L2 Fig title.png|In this project, you will build and analyze a Yagi-Uda dipole array using EM.Libera's Wire MoM solver.|
*[[Building_Geometrical_Constructions_in_CubeCAD | CubeCAD]]
*Array object
*Gap Source
In this tutorial you will use a wizard to build and analyze a multi-element Yagi-Uda wire antenna array. You will learn how to perform a parametric sweep simulation using the project's design variables.
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== Getting Started ==
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<td> [[Image:Libera L2 Fig1.png|thumb|left|720px|EM.Libera's wizard toolbar.]] </td>
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Keep the default settings for <b>Array Direction</b>, <b>Dipole Polarization</b>, and <b>No. Elements</b> as X, Y, and 5, respectibely, in the "Yagi Wizard Quick Settings" dialog window.
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<td> [[Image:Libera_L2_YagiWindow.png|thumb|left|400px|EM.Libera's Yagi Wizard Quick Settings dialog window.]] </td>
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[[Image:Libera L2 Fig7.png|thumb|480px720px|The radiation pattern dialog.]]
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The sweep variables list is initially empty. On the left side of this dialog, you see a list of all the available independent variables. Note that out of all the array-related variables you saw earlier in the variables dialog, only one called "n_direct" is listed here. This is the number of director elements in the Yagi-Uda array, and it is an independent variable. All the other array-related variables such as wire lengths, spacings, <i>etc</i>. are dependent variables whose definitions involve another variable called "lambda0_unit".
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Select "n_direct" from the left table and use the right arrow {{key|-->}} button to move it to the right table. Another dialog titled "Define Sweep Variable" opens up. You have to set the start, stop and step values of your sweep variable. By default, the sweep variable is of uniform type. Enter 5, 13, and 1 for the start, stop and step values, respectively. This will create a value list of {5, 6, 7, 8, 9, 10, 11, 12, 13}.
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Close Click on the {{key|OK}} button to close the parametric sweep settings dialog and return to the simulation run dialog. Run the sweep simulation. It may take a while as a total of nine individual WMOM simulations must be completed. At the end of the parametric sweep, you will see a total of nine 3D radiation pattern plots in the navigation tree. The figures below shows some of these plots.
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== Analyzing the Array Directivity Data ==
Open the data manager and plot the data file "D0_SweepFF_D0_Sweep.DAT" in EM.Grid. You should see a graph like the figure below. It shows the variation of the directivity (D0) of the array as a function of the number of director elements.
An almost linear variation is observed.
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Next, while still in the data manager, view the contents of the data file "D0_SweepFF_D0_Sweep.DAT" in a spreadsheet using the {{key|View}} button of this dialog.
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You can perform a least squares fit of your data in [[EM.Cube]]'s data manager. From the top menu of the spreadsheet, select the menu item '''Compute → Least Squares Fit...'''. In the Least Squares Fit dialog, choose "n_direct" and "FF_1_D0" as the X and Y data columns and enter "D0_Fit" for the name of the new column to be created. Click the {{key|OK}} button. A new column named "D0_Fit" is added to the spreadsheet.
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<td> [[Image:Libera L2 Fig23.png|thumb|left|480px|The data manager's least squares fit dialog.]] </td>
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<td> [[Image:Libera L2 Fig24.png|thumb|left|480px|The data manager spreadsheet showing the newly added data column called "D0_Fit".]] </td>
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Next, you are going to plot both data sets in EM.Grid. While still in the spreadsheet, go to the top menu and select the menu item '''Plot → Cartesian...'''. In the Data File Plot dialog, choose "n_direct" and "FF_1_D0" as the X and Y data columns and click the {{key|OK}} button to plot the first data set in EM.Grid. This is identical to your earlier directivity graph.
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<td> [[Image:Libera L2 Fig25.png|thumb|left|480px|The data file plot dialog showing the first data set selected.]] </td>
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Now go back to the Data File Plot dialog again, and this time choose "n_direct" and "D0_Fit" as the X and Y data columns.
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<td> [[Image:Libera L2 Fig26.png|thumb|left|480px|The data file plot dialog showing the second data set selected.]] </td>
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Click the {{key|OK}} button to plot the second data set in EM.Grid. The two plots are overlaid in the same graph as shown in the figure below.
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<td> [[Image:Libera L2 Fig21.png|thumb|left|480px|Plots of the two data sets "FF_1_D0" and "D0_Fit" as functions of "n_direct".]] </td>
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