TRL Cal Kit Design Wizard


Requires Advanced Calibration (5xP) PLTS license.

This wizard helps you design and verify 2-port TRL Cal Kit standards.  

Note: This wizard is NOT used to design Differential (Balanced) TRL Cal Kits.

To launch the TRL Cal Kit Design Wizard

Click Calibration, then Design TRL Cal Wizard

The following wizard pages are presented in order:

  1. Start

  2. Design the TRL Cal Kit.

  3. Coaxial Calibration

  4. Measure the TRL standards

  5. Verify Freq. Ranges

  6. Analyze Launch Lines

  7. Update Cal Kit to PNA

  8. Perform TRL Cal

  9. Measure Cal Standards

  10. Analyze Cal Quality

1 Start

Welcome dialog box

To save your progress, click File, then Save on any TRL Wizard page.

To continue your work at a later time, click File, then Open, and select your *.wzd file.

Cal Kit definitions are stored at the following steps:

  • 2  Design  The Cal Kit Design values.  Click Update Cal Kit to restore the definitions to these values.

  • 5  Verify Frequency Range  Click Update Cal Kit to save the optimized values to the *.wzd file.

  • 6  Analyze Launch Lines  Click Update Cal Kit to save the optimized values to the *.wzd file.

  • 7 Update Cal Kit to PNA  View the Cal Kit definitions. Then click Upload to PNA to save the Cal Kit to the PNA.

S2P files that contain TRL Standard measurements can be stored at Step 4 and Step 7.

2 Design

Design Cal Kit dialog box

This page helps you to design the TRL standards that you will fabricate. Enter design information at the top of the page and press Calculate.  PLTS recommends the physical lengths of each standard to fabricate and the Frequency Range and Delay of each.

All standards are assumed to operate at 50 ohms.

Design Inputs

Start and Stop Freq (MHz)  Enter the frequency range over which the TRL Cal Kit will be used.

Use Load  Check if a Load standard will be fabricated.

Load Max. Freq (MHz)   Enter the frequency range over which you would like the load standard to be used.

Reflect Type  Select the type of reflection standard to be used (Short or Open).

Freq Ratio (2-10)  The ratio for each of the Line standards can be no less than 20° and no more than 160°.  Multiple bands are required to cover the entire frequency range.  

For example: 160° / 20° =  8 and 150° / 30° = 5. Although the allowed ratios are 2 through10, ratios higher than 8 may result in degraded accuracy of the line standards.

Effective Dk (dielectric constant)   Enter the dielectric constant of the medium of the standards.

Reference Length (1/2 Thru)  Enter 1/2 of the length (in mm or inches) of a reference Thru. This would be the length of a Thru standard that is exactly the length of a THRU that extends from launch to launch.

Calibration Standards Definitions

When Calculate is pressed, the displayed values are updated to show the Standard, Frequency Range, Delay (in picoseconds), and the physical length of each standard.

Update Cal Kit Definitions

Cal Kit Name  Type a name for your new Cal Kit as it will appear in the PNA.

Cal Kit Description  Type a description for your new Cal Kit as it will appear in the PNA.

Connector Type  Enter the type of connector that is used on your new Cal Kit.

Update Cal Kit   Resets the Cal Kit definitions to designed values. Do this if the definitions were modified in Step 5 and Step 6 and you want to revert to the designed values.  Use Step 10 to download the updated Cal Kit to the PNA.

Save your progress in the wizard

Click File, then Save. To continue your work after fabricating the standards, click File, then Open, and select your *.wzd file.

3. Coaxial Calibration

3. Coaxial Calibration dialog box

After the TRL standards have been fabricated, this step calibrates the PNA before measuring the standards.

1. Measurement Setup

Click Modify to change the stimulus parameters for measurement of the TRL standards. Launches the Setup Hardware Dialog.

2. Cal Kit Selection

Click Modify to launch the Calibration Settings dialog.

3. Perform Calibration

Enter a name for the Cal Set that will result from this calibration. Click Calibrate to begin the PLTS Calibration Wizard.

 

Load PNA Cal Set. Instead of performing a Coaxial Cal, select a Cal Set on the PNA.

4. Measure Standards

Measure Cal Standards dialog box

After the PNA is calibrated, existing files can be opened or the standards can be measured, and then analyzed in the following steps.

  1. Click the Browse buttons to find existing S2P files to view.

  2. Then click Next>. Do NOT click Measure.

* Or *

  1. Click the Browse buttons.

  2. Then navigate to a folder where the resulting S2P files will be saved.

  3. Then click Measure to launch the Connect DUT page which measures the TRL standard.

Click Next> when all standards have been opened or measured to continue with the Verify Frequency Range page.

 

Connect DUT dialog box

This dialog allows you to test the connection of the DUT. When the connection is made, click OK to measure the DUT, store the results in the specified file, and return to the Measure Cal Standards page.

Reflection, Transmission, Customize   Check the boxes to list the parameters that are available for testing to the specified criteria. Click each parameter (in the highlighted area above) to select for testing. The BOLD parameters are selected.

Pass/Fail indicator (Green box in red ring above)  

  • Green = Selected parameters pass the specified criteria.

  • Red = Selected parameters FAIL the specified criteria.

Criteria   Click to launch the Continuity Check Criteria dialog.

Trigger Checking  

  • Continuous - measurements are made continuously while the selected parameters are tested.

  • Single - one measurement is made when the Single button is pressed and the selected parameters are tested.

Click OK when the DUT is connected to your satisfaction.

 

Continuity Check Criteria dialog box

This dialog sets the Pass/Fail criteria for the Continuity Check.

Select   Choose an existing criteria. If only 'default' exists, click New to create new criteria settings.

New  Click to launch the Input New Name dialog. Type a name for the new criteria settings.  The name of the settings in the above image is "Reflection".

Delete  Removes the selected Criteria settings.

Rename  Allows you to rename the selected Criteria through the Input New Name dialog.

Save  Saves the current settings to the selected Criteria.

OK  Close the dialog.

5 Verify Frequency Range

Verify Frequency Range dialog box

Use this page to analyze the results of the measured TRL standards in the Frequency domain.

Select a standard to view.

Things to check:

  • Compare the insertion loss of the Line standards with that of the THRU.  The difference must be between (20° and 160°).

  • Move the markers to change the “Measured” properties - they are defined as the data between the two markers.

  • The default measured start and stop frequency (the default locations of the markers) are calculated from the frequency ratio. For example, if the ratio is 5, then the measured frequencies are calculated from 30° and 150° frequency points.

  • The measured delay is the average group delay.

  • The frequency response is fitted with a linear line. Compare the response with the line: the phase and magnitude linearity are defined as the most positive – most negative value.

  • Note: there should be NO frequency gaps between adjacent lines.

Load Standard

In TRL calibration, a load standard is often utilized to cover the low frequency band.

Specify the maximum acceptable return loss as the “Maximum Return Loss”. This means the load return loss must be lower than this value within its designed frequency range. The frequency corresponding to the “Maximum Return Loss” is defined as the load stop frequency.

The load standard is required to have a low return loss (approx -50 dB). The return loss becomes worse at higher frequencies.

Reflect Standards

The phase response of the Reflect standard is compared with the Thru and the phase difference is used to calculate the delay.

Verify Cal Kit Standards   Select a TRL standard to analyze. Data is presented in the middle of the dialog.

(Line / Thru).

Measured - Designed - Maximum

  • Phase and Magnitude Linearity is Measured ONLY.

  • The corresponding data is plotted to the right - Magnitude on top; Phase below.

  • Right-click, Drag Zoom, or slide the markers on each plot to show the data that best represents your standard. Learn more about these controls.

  • The Measured and Maximum data is updated accordingly.

Modify Cal Kit Definitions

The measured values are optimized values.

Use this values or enter new Start and Stop frequencies, and Delay values, for the Cal Kit.

Reset  Clears the values that are entered.

Update Cal Kit  Saves the new displayed values to the *.wzd file on your PC.

6 Analyze Launch Lines

Analyze Launch dialog box

The data that is presented here is the same measurement data as the previous page, but in Time domain.

Use this dialog to analyze the quality of the launches used in your fixture. In TRL calibration, the line impedance is often used as the reference impedance.

Move the markers to specify a range to calculate the impedance variations, showing as a peak or a dip possibly. That is a measure of the launch repeatability.

For the lines, you can select a line and specify the range for the line.

Press Re-calculate to view the new Nominal Impedance values.

Update Cal Kit  Saves the new displayed values to the *.wzd file on your PC.

7.  Upload Definitions

7. Current Cal Kit Definitions dialog box

This page enables you to view the current cal kit parameters.

You can also download the updated cal kit definitions to the PNA.

8 Perform TRL Cal

8. TRL Calibration  dialog box

Perform a TRL Calibration using the new standards to verify the performance of the Cal Kit.

Click Modify to change the start frequency, stop frequency, or cal kit.

Type a filename for the Cal Set when the calibration is complete.

Then click Calibrate to perform the TRL calibration.

Load PNA Cal Set. Instead of performing a new TRL Cal, select a Cal Set on the PNA.

9. Remeasure TRL Cal Stds

9. Re-Measure Cal Standards dialog box

After the PNA has been calibrated using the new TRL calibration standards, existing files can be opened or the standards can be measured, and then analyzed in the following steps.

  1. Click the Browse buttons to find existing S2P files to view.

  2. Then click Next>. Do NOT click Measure.

* Or *

  1. Click the Browse buttons.

  2. Then navigate to a folder where the resulting S2P files will be saved.

  3. Then OPTIONALLY click Connect to launch the Connect DUT page to check the connections.

  4. Then click the RED button to measure the TRL standard. The button will turn to green when the measurement completes.

Click Next> when all standards have been opened or measured to continue with the Analyze Cal Quality page.

10  Analyze Cal Quality

10. Analyze Cal Quality dialog box

Allows you to view the measurements of the new TRL standards that were just used to perform the TRL calibration.

Repeatability

Select Forward or Reverse measurement for the Thru and Line standards.

  • THRU standard - The S21 magnitude response should be very flat. The phase response should be close to zero.

  • REFLECT standard - The S11 return loss should be very good. The phase response for an OPEN should be 180 degrees; a SHORT should be 0 degrees.

  • LINE standards - Since each line is only used over part of the frequency range, the data where the line was used for calibration is repeatability. Where it was not used, it is more realistic of the performance of the calibration kit. The S11 and S22 return loss should be very good within the specified range, since this is measurement repeatability. Outside the range, the return loss will be higher and more realistic for the line's performance. For transmission parameters, S21 and S12, it is difficult to see the difference in two regions.

Note: It is important to realize that any variation from 'perfect' responses within the specified frequency range should be attributed to system repeatability, either in the standards or in the PLTS system.


Last Modified:

17-Sep-2019

Corrected "LINE standards" description

14-Dec-2012

Added reverse and re-ordered

8-Oct-2009

Several Edits

20-Nov-2008

New topic