Designing and Simulating a Microstrip Patch Antenna
Designed by
Raza Hussain
Introduction A microstrip patch antenna consists of a very thin patch, which is placed at a small fraction of wavelength above a conducting ground plane. The patch and the ground plane are separated by a dielectric. The patch conductor is normally copper and can assume any shape, but regular shapes are generally used to simplify analysis and performance prediction. The relative permittivity (εr ) of the substrate is an important parameter to consider, because it enhances the fringing fields that account for radiation. A microstrip patch antenna is characterized by its length L, width W , and thickness h, as shown in the figure below:
Where,
h = height of the substrate
Objective The objective of this lab is to construct and analyze a rectangular patch antenna using AWR Microwave Office.
Creating the Schematic Diagram Follow the steps below to create the schematic diagram of a patch antenna: •
Click Project in the menu bar and select Add Schematic > New Schematic, and name it “Patch”.
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Select Elements tab from Project Browser, and select Microstrip.
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Select Lines, and select MLIN from the types of lines which appear below.
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Drag a line into the schematic window and place it there. The length and width of the line can be changed by selecting L and W respectively, above the line. This is shown in the following figure:
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Select four lines in the same manner, and place them orthogonally to each other.
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Select Obsolete from the drop down menu of Microstrip, and select MBEND.
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Drag this bend into the schematics window and place it there. The width and angle of the bend can be changed by selecting W and ANG respectively. This is shown in the following figure:
In the same manner select four bends and connect them to the lines, as shown in the following figure:
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Select all the objects in the schematic by pressing Ctrl+A, and click on New Schematic Layout View. A new window will open. In this window again select all the objects, and click on snap together . Both these buttons are present in the toolbar.
Creating the EM Structure Click Project and select Add EM Structure > New EM Structure. •
Double click Enclosure in the Project tab. A window will open which will contain the dielectric information. Under Enclosure enter the following values:
X-Dimension = 100 Y-Dimension = 100 X-Divisions = 200 Y-Divisions = 200 •
Now click Dielectric Layers and enter the information. Now click Boundaries and select Approximately Open and Perfect Conductor .
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Copy the image from Schematic 1:2 and paste it in the EM Structure.
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Select Rectangle Conductor from the toolbar and add a conductor of 3mm x 17mm in the EM Structure, and connect it to the antenna structure.
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Again select Rectangular Conductor , and fill the gap between the lines.
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Now select all and click Edge Port, and add a port at the terminal of the 3mm x 17mm conductor. The result will be like shown in the following figure:
Creating Graph •
Click Project and select Add Graph.
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Select the Rectangular plot.
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Options > Project Options, and then add the start, stop and step frequency, and click apply. After this click Ok.
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Right click “Graph 1” in the project tab and select Add Measurement.
Measurement Type: Port Parameters Measurement: S Data Source Name: EM Structure 1 To Port Index: 1 From Port Index: 1 •
Click Apply, and then click Ok.
Adding Project Frequencies 1. Choose Options > Project Options. The Project Options dialog box displays. Click the Frequencies tab to specify global frequency values. 2. To specify a frequency sweep, enter values for Start, Stop, and Step. To specify a frequency point, select the Single Point check box, and enter a Point value. 3. Click Apply and then OK.
Analyzing the Design Click simulate > analyze
