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In this tutorial you will use a wizard to crate the geometry of a parabolic dish reflector. You will learn how to define and use a short dipole source and a far-field radiation pattern observable.
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==Getting Started==
== Constructing the Parabolic Dish Reflector Geometry ==
Click on the <b>Parabolic Reflector Wizard</b> button [[Image:ParabolicReflectorWizardIcon.png]] button of the Wizard Toolbar or select the menu item '''Tools → Component Wizards → Parabolic Reflector'''.
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You can also measure the aperture diameter yourself using [[Building_Geometrical_Constructions_in_CubeCAD | CubeCAD]]'s distance tool. Click the '''Distance Tool''' [[file:Measure tool tn.png]] button of the '''CAD Toolbar''' or select the menu item '''Tools → Measure → Distance'''. Hover the mouse over the left right snap point of the paraboloid object to highlight it. The color of the object turns into translucent yellow and a small dark blue ball appears at the location of the snap point. Click the left mouse to establish the first point of the distance vector. Then move the mouse in the opposite direction and hover it over the right left snap point of the paraboloid object to highlight it. At this point a small dialog on the lower right corner of the screen shows a distance of 300mm.
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Next, define a far-field Radiation Pattern observable. To do so, right-click on the '''Far-Field Radiation Patterns''' item in the Observables section of the navigation tree and select '''Insert New Radiation Pattern…''' from the contextual menu. This opens up the Radiation Pattern dialog. Accept most of the default settings. Change the default 5° value of the '''Angle IncrementIncrements (deg)''' parameter to 1° for both Theta and Phi angles. In the "Additional Radiation Characteristics" section of the dialog, check the boxes labeled '''Max Side Lobe LevelsAxial Ratio (AR)''', '''Half Power Beam Width(HPBW)''' and '''First Null Parameters'''.
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[[Image:Illumina L3 Fig11.png|thumb|left|480px720px|The radiation pattern dialog.]]
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[[Image:Illumina L3 Fig12.png|thumb|left|640px720px|The geometry of parabolic reflector, its short dipole source and the three field sensor planes.]]
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Finally, visualize the 3D radiation pattern of the parabolic dish reflector on both linear and dB scales. From the radiation pattern plot, you will see a very narrow main beam with a very high directivity of 320.2 1 (≅ 25.05dB).
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== Examining the Radiation Characteristics of the Antenna ==
Plot the 2D radiation patterns of the reflector antenna in EM.Grid. Open the data manger and select the data files "FF_1_PATTERN_Cart_XY.DAT" and "FF_1_PATTERN_Cart_ZX.DAT". Open the Edit Graph Properties Settings dialog for each plot and change their data format to '''dB_Field_Scale'''. Then plot both graphs in EM.Grid. From the graphs below, you can see that the side lobe levels of the radiation patterns in the two principal XY and ZX planes are less than -16dB and -22dB, respectively.
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| FNB_ZX.DAT || First null bandwidth in ZX palne || 44°
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| FNB_XYFNL_XY.DAT || First null level in XY palne || 0.0842
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| FNB_ZXFNL_ZX.DAT || First null level in ZX palne || 0.0599
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