Guidance Required for nRF9151 Antenna RF Certification Testing and VNA Validation

[Milan Pipaliya]

Hello Nordic Community,

We are developing a custom product based on nRF9151 using NCS SDK v3.1.0.

On the hardware side, we have already completed antenna matching and tuning activities, including component optimization of the matching network. We are currently performing VNA (Vector Network Analyzer) measurements to verify antenna performance (S11/Return Loss) across the required LTE frequency bands.

For RF validation and certification preparation, we would like guidance on the recommended testing methodology from Nordic.

We found the following modem RF test command:

AT%XRFTEST=1,1,28,7000,23,1,4,1,0,0,0,0

Example configuration:

• Band 28
• 700 MHz
• LTE-M (Cat-M1)
• +23 dBm TX Power
• CW Modulation

Our current validation approach includes:

1. Antenna tuning and matching network optimization.
2. VNA measurements (S11/Return Loss).
3. Firmware-based RF transmission testing using %XRFTEST.
4. Planned conducted and radiated measurements in an RF laboratory.

We would appreciate guidance on the following:

1. Is %XRFTEST the recommended and valid method for RF antenna testing and certification preparation on nRF9151?
2. Which firmware/modem firmware version is recommended for laboratory RF testing?
3. After VNA verification, what additional RF validation steps are recommended by Nordic before certification?
4. Are there specific Nordic procedures for:
   • Conducted TX measurements
   • Radiated antenna measurements
   • Output power verification
   • Band and frequency verification
   • LTE-M certification pre-compliance testing
5. Can certification-related RF measurements be performed using firmware-controlled test commands such as %XRFTEST, or is there a dedicated Nordic test methodology that should be followed?
6. Are there any limitations of %XRFTEST when compared to certification lab test procedures?

We are looking for guidance on the complete validation flow, including antenna tuning, VNA measurements, firmware-based RF testing, and certification testing for an nRF9151-based design.

Thank you for your support and guidance.

Best Regards,
Milan