Vitalizing Electromagnetic Concepts To Obtain Relevancy
The VECTOR Project

ECEN3613
Electromagnetic Fields

 

 

Sonnet tutorial                                   

 

How to run Sonnet and read .geo file created by the GUI:

  1. Downloading Sonnet Lite 12.53:

    *This step is only necessary if Sonnet Lite is not already installed, otherwise skip to step 2.

    1. Go to http://www.sonnetusa.com/products/lite/download.asp. This will link directly to the Sonnet Lite 9 downloading page.
    2. Select one of the two choices to download sonnet Lite9. All the instructions about how to install sonnet Lite 9 to your computer are given on the Website.
    3. You must register the software after you download it.

     

  2. Opening .geo file created by the filter design GUI:
    1. Double click on the Sonnet short-cut icon or select start >> sonnet  >> sonnet from the windows desktop start menu. The Sonnet taskbar should appear on your screen.

       

    2. On the Sonnet task bar, select project >> edit >> browse for project….

      Figure 1: Sonnet taskbar

      This opens a new window where you will be able to browse through the directories. Go to the directory where the file name .geo (created by MATLAB) is saved and select the file. The geometry file (.geo) should be saved in the ‘Data’ folder in the directory where the extracted zipped GUI files are located.

       

    3. After you select your .geo files, A new window will open. On the taskbar of this new window, it should say xgeom. You should be able to see the drawn boxes in this window.

    Figure 2: An open .geo file in Sonnet

  3. Setting up Circuit Properties:

    1. On the xgeom 12.53 window select Circuit >> Units. The Length units should be set automatically to mm, but make sure the frequency unit is set to GHZ.

      Figure 3: Unit Setup

    2. All the other units should be set as shown in the picture above. Also, make sure you put a check mark on Remember settings.
    3. Click OK.

  4. Analyzing the circuit:
    1. Setting up the Analysis:
      bullet On the xgeom window, select Analysis >> Setup.
      bullet A new window will pop up. Select linear frequency sweep from the list under Analysis
        Control.
         
      bullet     If you are not sure what step frequency you need to choose, select Adaptive Sweep
        (ABS). But If you use linear frequency sweep, make sure that you choose such step
        frequency that you have enough points on the plot to verify your simulation. For example,
        in case of microstrip filter design, if your cutoff frequency is 4 GHz and stopband frequency
        is 7 GHz, it would be good to select your start frequency 0.1 GHz, Stop frequency
        8 GHZ, and the step frequency 0,1. For Patch antenna design, if your resonant frequency
        is 3 GHz, you should choose the start frequency 2.5 GHz,  stop Frequency in between 3.5
        and 4.0 and step frequency 0.01.

      Figure 4: Frequency sweep set up

      bulletClick OK.

 

b.  Calculating the Memory:

After the microstrip is drawn in sonnet, take into account that there is a 16 MB limit of memory that the program can use to simulate. You need to verify that this limit is not exceeded.

bulletSave your design.
bulletGo to Analysis >> Estimate Memory.
bulletIf your design is too complex and requires more than 16 MB of memory, it will give an error message about the memory. If your simulation requires too much memory, you can follow the following steps:

 

bulletGo to Analysis >> Setup.

bulletChoose Speed/Memory.
bulletMove the cursor to one of the lesser accuracy setting.
bulletFrom here you can click the Memory key and the memory will be calculated once again.
bulletClick OK.

If the memory is still to high follow these steps:

bulletOn the drop down menu click on Circuit >> Box... A window should pop up that looks like the figure below.
bulletOn the upper right corner of the pop up window under Covers, select Top Metal drop down menu and change it to Free Space.
bulletThen check the Symmetry box located center right of the pop up window and hit the Apply button.

 

Figure 5: Box Settings set up

 

bullet

Next click the Cell Size Calculator button. Another window will pop up that looks like the figure below. Make sure Wizard is selected and hit the Next button.

Figure 5: Cell Size Wizard

 

bullet

The next menu that shows up asks you to type in the X Target values.  Put in all of the lengths here for your filter sections including the transmission/feed lines, then click Next.

Figure 6: Inputting the X Target values.

 

bullet

The next window is the same thing except it is now asking you to enter in the Y Target values.  Put in all of the widths of your filter sections here, then click Next.

bullet

The next window asks you for the tolerance value just leave it at the default value and hit Next.

bullet

The next window that pops up has several buttons to push. Click the Estimate Memory button which can be seen on the figure below.  (Note: If there is an error follow the instructions given to correct the problem). Now you memory should be a lot less.

Figure 7: Estimating the required memory.

bullet

Click the Finish button to exit the pop up window.

bullet

Then for the next window hit the Apply  button and then Ok.

bullet

If you want to go back and add more frequency points.

 

c. Analyze:
bulletGo to Project >> Analyze.
bulletIf your project has not already been saved, it will ask you to save data.geo. You can click save, which will create a project file (.son). Later on, if you want to simulate it again, you can just open up this project file.

  1. Graphing the Circuit:
bulletAfter you are done analyzing, select Project >> View Response >> new graph.

Figure 8: Graphing the circuit

bulletAdding Curves to the graph: If you want to add a graph or see another waveform simply double click on DB[S11] and the below pop up menu will appear. To add, simply double click on the S-parameters that you want to view or delete. More than one graph can be shown at the same time. For this project, the S-parameters that need to be plotted are the S11, and S21 parameters both Magnitude and Phase [Note: Why is there a phase shift?].  As a reminder, remember that S11 represents the reflection coefficient of the filter while S21 represents the transmission coefficient of the filter. 
bulletAlso, plot the input impedance, Zin. This found by changing the Data Type to Zin. [Note: What happens to the input impedance versus frequency?  Looking at the input impedance data, how does the lowpass filter really filter out the higher frequency?]

 

Figure 9: Adding more curves

5.  Exporting project data to a spreadsheet:

  1. Go to the graphing window (emgraph). Click on file >> Export >> Project data.
  2. It will pop up the following window. Make sure the format is set to Spreadsheet, Parameter is set to S-param, and complex is set to DB-angle.

     

    Figure 10: Exporting project Data

     

  3. Click Save.

 

 

 

 

This project is sponsored by the National Science Foundation under award NSF00311257.  All material is property of the authors and can be used only with permission. For further information contact the REAL LIFE Co-ordinator.