Performing Impedance Calibration

• Overview

• Selecting Calibration Kit

• Performing Open/Short/Load/(Low-Loss C) Calibration

• Acquisition Status of Calibration Coefficient

Other topics about Performing Calibration

Overview

The impedance calibration is a calibration function dedicated to the impedance analysis with the E5061B option 005. The impedance calibration executes the 3-term calibration (open/short/load calibration) directly in the impedance domain instead of the S-parameter domain, after the raw S-parameter measurement data or the gain-phase T/R measurement data is converted to the impedance data. Therefore, you need to select your desired impedance measurement method before performing the impedance calibration. The impedance calibration basically consists of the open, short, and load calibrations. You can perform the optional low-loss capacitor calibrations in addition to the open/short/load calibrations. The impedance calibration is applied only to the impedance parameters (see Data Processing). It is not applied to the S-parameter and Gain-Phase T/R ratio measurements.

The following table shows the recommended calibration for each method. Note that the calibrations for network analysis such as the 2 port full and  response through are used in the Shunt-Thru methods, instead of the impedance calibration.

Recommended Calibration

Difference of Calibration (for S-parameter) and Impedance Calibration

• The impedance calibration executes the 3-term calibration in the impedance domain after the S-parameter or Gain-Phase T/R ratio is converted to the impedance.

• The impedance calibration supports the low-loss capacitor calibration.

• The impedance calibration is not applied to the network analysis data (S-parameters and Gain-Phase T/R ratio).

The impedance calibration and the calibrations for network analysis, such as the 1-port full, 2-port full, and response through cannot be performed at the same time. If you perform the impedance calibration after performing these network-analysis calibrations in the same channel, the data of network-analysis calibrations is overwritten and deleted.

Low-Loss Capacitor Calibration

When you measure Q, D, and ESR of RF capacitors and RF inductors by using the reflection method with the 16201A terminal adapter and Keysight’s 7 mm test fixtures, performing the low-loss capacitor (LLC) calibration in addition to the open/short/load improves the accuracy of Q, D, and ESR measurements at high frequencies over 1GHz. The LLC provides a reference for calibration with respect to the 90°-phase component of impedance. Keysight 16195B calibration kit provides a low-loss capacitor termination in addition to the open/short/load terminations

Selecting Calibration Kit for Impedance Calibration

You need to select calibration kit before you perform the impedance calibration.

1. Press Cal > Cal Kit.

2. Select your calibration kit.

Performing Open/Short/Load/(Low-Loss C) Calibration (Impedance Calibration)

Impedance calibration should be performed at the following location.

1. Press Channel Next (or Channel Prev) to select the channel for which you want to calibrate (If you are using multiple channels).

2. Confirm if the desired method is selected (Meas > Method).

3. Press Cal > Calibrate > Impedance Calibration.

4. Connect the open termination, or leave the fixture’s measurement terminals open.

5. Click Open to execute open calibration (After the calibration is performed, a check mark is displayed at the left of the softkey).

6. Connect the short termination to the location of the open termination, or short the measurement terminals of the fixture.

7. Click Short to execute short calibration.

8. Connect the load termination in place of the short termination, or connect the 50 Ω resistor to the fixture.

9. Click Load to execute load calibration.

10. If you use the 16201A terminal adapter and the 16195B 7 mm calibration kit, you can perform the optional low-loss capacitor calibration here. Follow the procedure below:

    1. Connect the Low-Low capacitor termination instead of the load termination.

    2. Click Low-Loss C (Optional) to execute the low loss capacitor calibration.

11. Click Done to complete the impedance calibration process. Upon pressing this key, calibration coefficients are calculated and saved. The error correction function is also enabled automatically.

12. Cor is displayed at the Channel Window.
    (If there is no impedance parameters in the channel, Cor is not displayed. For example, when only S11 is displayed at the trace, Cor is not displayed even after impedance calibration. Changing the parameter to |Z| displays Cor.)

Acquisition Status of Calibration Coefficient

As in the S-Parameter measurement, the calibration property (Cal > Property) shows the acquisition status of Impedance calibration.

The following example shows that impedance calibration performed with Port 1-2 Series method.