In this dialog box, define a new Material name (e.g. Substrate) and set the Type to a Normal dielectric material. Afterwards, specify the material properties in the Epsilon and Mue fields. Here, you only need to change the dielectric constant Epsilon to 2.33. Finally, choose a color for the layer by pressing the Change button. Your dialog box should now look similar to the above picture before you press the OK button.
Please note: The defined material Substrate will now be available inside the current project for the further creation of other solids. However, if you want to also save this specific material definition for other projects, you may check the button Add to material library. You will have access to this material database by clicking on Load from Material Library in the Materials context menu in the navigation tree.
Back in the brick creation dialog box you can also press the OK button to finally create the substrate brick. Your screen should now look as follows (you can press the Space bar in order to zoom the structure to the maximum possible extent):
? Model the Ground Plane
The next step is to model the ground plane of the patch antenna. Because the antenna will be excited by a coaxial feed at the bottom face, the electric boundary at Zmin defined by the previously chosen template is not suitable as a ground plane. Consequently, a metallic brick must be additionally defined. First, the model has to be rotated by activating the rotation mode View Mode Rotate (). Then the bottom face has to be activated by the face pick tool (Objects Pick Pick Face, ), double-clicking on the substrates bottom face. The face selection should then be visualized as follows:
You can now extrude the selected face with the Extrude tool (
). Here, you must enter the
height and the material of the new shape to be created. In this example, the ground plane must have a non-zero thickness because of the coaxial feed that will be modeled later. In CST MICROWAVE STUDIO a port region must be homogeneous for at least three mesh lines in longitudinal direction. You can therefore choose a Height of 2.1 mm, representing three times the substrate thickness, as a sufficient dimension. Enter this value in the following dialog box and select PEC from the Material dropdown list as the metallic material property:
?
After entering a suitable name (e.g. ground) in the Name field and confirming your settings with the OK button, the current structure will look like this (rotated again to the see the top face):
? Model the Patch Antenna
After the ground plane has been defined, the patch antenna must be modeled as a cylindrical shape on the substrates top face. Please activate the cylinder creation mode (Objects Shapes
Cylinder,
coordinates numerically by pressing the Tab key to open the following dialog box:
Basic
). Similar to the construction of the substrates brick, enter the
Here, enter the center point of the cylinder with X = 0 and Y = 0 because the patch is located symmetrically on the substrate. Afterwards, please define the Radius with
23.2 mm and the Height with 0.07 mm in the shown dialog boxes that appear after you have pressed the Tab button:
Skipping the entry dialog for the inner radius by pressing the Esc button will lead to the following dialog box that provides a summary of your entered parameters:
Select PEC as the Material setting for the patch and assign a meaningful name to the brick by entering e.g. patch in the Name input field.
Again, please check the settings carefully and change any mistakes in the corresponding entry field. After you apply the settings with the OK button, your screen should show the following structure: