Load Pull Measurement Data Import Utility

The Load Pull Measurement Data Import utility is used to import Maury or Focus Loadpull measured loadpull data in Agilent's Advanced Design System (ADS) for interpolation and generation of load and source pull contours. It is assumed that the data is generated for a constant bias, fixed frequency and constant input power.

The Load Pull Measurement Data Import utility can be selected and installed during installation process of ADS. After installation, the Load Pull utility can be accessed from Schematic window.

The process includes:

• Importing Loadpull Measurement Data
• Preparing Data for Interpolation
• Interpolating the Data and Displaying Results

Importing Loadpull Measurement Data

Before you can use Loadpull Measurement Data Import utility, you must have measured loadpull data available on your system. If you do not have measured loadpull data, you can access and copy sample measured data file for Maury and Focus microwave system to your project directory by selecting DesignGuides > Loadpull > Sample Loadpull Data File.
To import loadpull measurement data:

1. In the Schematic window, choose DesignGuides > Loadpull > Loadpull Measurement Data Import Utility. Click OK. A dialog box appears.
2. Specify the File Format option. You can import either Maury or Focus measured data.
3. Select Select Loadpull Data File to open the File Selection dialog box. You can select either Browse or Load Output File.
   • Use the Browse option to select a specific data file from the project directory and define the output file name.
   • Use the Load Output File option to load a previously-prepared load pull data file. You can use this option if you have successfully prepared loadpull data earlier and you want to load it now. All the prepared loadpull file have an extension .lp . When selecting the data file, all the Measurement Variable for contour plots loads directly. You can add a Measurement Variable to Trace and Generate Contours.
4. Select the measured data file using Browse button and define the Output File Name. Click OK.
   
   During selection of loadpull-measured data file, the format of the loadpull impedance data is determined. If the impedance value is normalized to its characteristic impedance, the Data Format dialog box displayed during this process reflects these settings.
   
   In some cases, it is difficult to determine the data format correctly due to non-availability of measured data points across the entire Smith Chart region. In this case, you must make the changes manually. If the impedance values are not normalized and appear in the load pull file as, for instance, 52+j×32, check the Impedance Normalization check box and set the value of Zohm to the applicable normalized impedance (such as, 50 ohms).

Preparing Data for Interpolation

In this step, the tool reads the measurement points and prepares the data for interpolation. You also have an opportunity to select the measurement variables you want to plot.

To prepare data for interpolation:

1. In the Load Pull Utility dialog, select Prepare Loadpull Data to prepare the data for interpolation. The process takes all the measurement points and generates a triangular mesh to perform linear interpolation on scattered data. After the data is prepared for interpolation, the measurement variables for which the contours can be generated appear in the Measurement Variable field. The utility does not restrict the number of variables you can plot simultaneously. You can generate loadpull contours for multiple variables at the same time, provided you have valid measurement data to generate loadpull contours.
2. Select the variable from the Measurement Variable field and add to the Trace field. During this process you enter the minimum and maximum bounds for your contour plots and the number of contours you want to generate within defined bounds. Add all the Measurement Variables you want to plot to the Trace field.
   
3. Select Open New Data Display Page so you can plot loadpull contours on Smith Chart or on Polar Chart. (Note: to view contours on a rectangular grid, select Plot real(Variable_Name) vs. imag(Variable_Name)). For details on using the data display, refer to Plots and Lists in the Data Display documentation. Select the Output Mesh option to export the triangular mesh generated during Prepare Loadpull Data to a data display page. The output mesh can be plotted by plotting the variable Zmesh on the Smith Chart or Polar Chart. You can use the output mesh to view the measurement points and for debugging purposes.

Interpolating the Data and Displaying Results

The interpolation process generates load pull contours and displays the results.

To interpolate the data:

1. Click Generate Contours to start the interpolation process. This process interpolates the prepared data and generates load pull contours. At the end of the interpolation process, the data display opens.
2. Select the type of display from the list. During the translation process, the measurement variable name changes to remove all special character and a prefix "Z" is appended at the beginning. To view the new assigned name in the Data Display Variable Name, select the name in the Trace window.