Next-Level Measurements: Easier, Faster, and More Accurate with the New Picotest Component Test Fixture

Calibration and measurement accuracy are critical in power integrity and impedance analysis, but they’re often hindered by time-consuming setups, inconsistent connections, and external interference. Picotest’s new Calibration Test Fixture (CTF) addresses these challenges head-on, offering a faster, easier, and most importantly, repeatable measurement process. By eliminating the need for SMA connectors on mount boards and integrating internal ground loop isolation, the CTF streamlines your workflow while improving measurement reliability. Whether you're performing impedance analysis or a full 2-port VNA calibration, the CTF ensures consistent results, making it an essential tool for high-precision power integrity measurements.

The CTF kit comes with all the mounts necessary for impedance calibration and full 2-port calibration. This blog will specifically focus on impedance calibration and measurement on the Bode 500 VNA; however, the CTF is compatible with any VNA for full 2-port or impedance calibration.

Figure 1: Picotest's Calibration Test Fixture (left) and Calibration Boards for Impedance Calibration and Full 2-Port Calibration (right)

How to Calibrate Using the Calibration Test Fixture and the Bode 500

We will be walking through the VNA calibration and measurement process using the CTF on a Bode 500 for a Shunt-Thru Impedance Analysis, but this procedure can also be followed using the Bode 100. For impedance calibration, we will use the THRU, B100, and ISO SHORT boards, as shown in Figure 2.

Figure 2: Equipment Required for Impedance Calibration on the Bode 500

After powering on the Bode 500, with cables connected for calibration as shown in Figure 2, follow the steps below to calibrate your measurement setup prior to making measurements on your DUT. A torque wrench is included to help make sure your connections are secure and repeatable.

Step 1: In the Bode Analyzer Suite, if starting a new project, select Impedance Analysis > Shunt-Thru. Otherwise, open your existing project.

Step 2: Set your desired frequency sweep settings and change the Source Level  to 16 dBm (or 13 dBm if using the Bode 100). 

Set the Attenuator level to 0 dB and the Receiver Bandwidth to at least half of your start frequency.

• Setting the Receiver Bandwidth to half of your start frequency will allow accurate readings at the lower frequencies of your sweep while also maintaining a proper signal-to-noise ratio. The recommended initial starting point is setting this to 30 Hz. However, as per the Bode 500 datasheet the maximum dynamic range can be achieved by setting this to 10Hz if desired. Sweeps may take longer as the BW is lowered.

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Step 3: Under the Home tab, select the User-Range Impedance Calibration > Perform New Calibration.

Step 4: Perform the Open calibration using the THRU board. To do so, place the calibration board FACE DOWN on the CTF. 

Press FIRMLY and hold, as shown in Figure 3, then select "Start" next to Open in the Open/Short/Load calibration. Once the Open calibration is complete, you will see "Performed" next to the corresponding step.

• NOTE - if you receive an overload warning during the Open calibration, exit the calibration screen and increase the Attenuator level ONLY for the Open calibration step. Change the attenuation level back to 0 dB for Load and Short.

Figure 3: With the Calibration Board on the CTF, Press Firmly and Hold for the Entire Duration of Calibration Step

Step 5: Perform the Load calibration using the B100 board, with the same method as used in step 4.

Step 6: Perform the Short calibration using the ISO SHORT board, with the same method as used in step 4.

Step 7: Confirm that all calibration steps were completed, as shown in Figure 4.

Figure 4: Completed Calibration in the Bode Analyzer Suite

Step 8: Press Close to exit the calibration screen.

Step 9: Use the ISO SHORT board to obtain a noise floor measurement. This should be in the 10's of micro-ohms or better (see Fig. 5).

Figure 5: Noise Floor on Bode 500 After Calibrating with the CTF

Step 10: Always measure a known DUT after completing calibration to ensure you have obtained a proper calibration. Once you've confirmed your calibration, you are now ready to measure your component!

The full 2-port calibration on VNAs such as the Keysight E5061B or the Rohde & Schwarz ZNL will follow the same general steps (i.e., short, open, load for each individual port), then an additional step of a thru calibration measurement. For more detailed steps on 2-port calibration, see 2-Port Impedance Measurement using the P2102A Probe and E5061B VNA.

How to Measure a DUT Using the CTF and Bode 500

To measure a DUT, simply mount your component on a CTF mount board and press and hold this board onto the Picotest CTF, similarly to what was done during calibration (See Figure 3). Begin the sweep by going to the Home tab and pressing either Continuous or Single. Save your waveform by pressing Measurement > New Memory in the rightmost pane of the Bode Analyzer Suite. Ensure you hold your DUT to the CTF for the entirety of the sweep (~30 seconds) to maintain accuracy on the Bode 500.

Conclusion

The Picotest Calibration Test Fixture (CTF) simplifies and enhances the calibration and measurement workflow on VNAs, delivering faster setup times, more reliable results, and the repeatability required for confidence in analysis. By removing common sources of error, the CTF sets a new standard for impedance and 2-port calibration accuracy when measuring components. This makes it an invaluable tool for anyone working in power integrity, RF, or high-speed signal environments. In an upcoming blog post, we’ll explore how the CTF DC Bias Adapter features enable accurate and convenient DC bias measurements on the Bode500, expanding its impedance analysis capabilities even further. Stay tuned!

References

1. Omicron Bode 500 Vector Network Analyzer | Signal Edge Solutions

2. Omicron Bode 100 Vector Network Analyzer | Signal Edge Solutions

3. 2-Port Impedance Measurement using the P2102A Probe and E5061B VNA | Signal Edge Solutions

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