Hello folks,
I need some help troubleshooting a BLE antenna issue on our custom nRF52840 PCB. Any insights would be greatly appreciated!
Issue:
- BLE sometimes advertises on a mobile phone but disappears after a few seconds.
- Other times, it doesn’t advertise at all.
- Device is not consistently connectable.
- We suspect the Pi filter matching may be causing the problem.
Troubleshooting So Far:
MCU Check: Blink program works, confirming the MCU is functional.
Antenna Tests:
- External FPC antenna sometimes advertises but won’t connect; other times, it doesn’t advertise at all.
- Tried multiple FPC antennas from a local supplier—same issue persists.
PCB Details:
4-layer board
- Top Layer: Ground Plane
- 2nd Layer: Ground Plane
- 3rd Layer: Power Plane
- 4th Layer: Ground Plane
Antenna Setup: - Ceramic Antenna: W3008
- External FPC Antenna: (Locally sourced, inconsistent performance)
Pi Filter Matching Calculations – Need guidance on adjusting the matching network for better RF performance. General BLE RF Debugging Tips for custom PCBs.
I can provide schematics, layout snapshots, or test results if needed. We don't have inhouse VNA or Spectrum Analyzer only oscilloscope.
Thanks in advance for your help!
