nRF9151 Antenna detection

[Vincent44]

Hello,

I am currently working on a new design based on nRF9151. This design is the evolution of a previous PCB.

The device uses a combined GPS and Cellular antenna, which is accessible by the user, since it's on an external SMA connector.
Therefore, the user might remove the antenna.

Looking at these documentation, I was wondering if it was possible to detect wether the antenna is connected or not. The idea is that the firmware is able to detect if the user has removed the antenna, and prevent any GPS/Cellular operations.

https://docs.nordicsemi.com/bundle/nwp_033/page/WP/nwp_033/nwp_033_antenna_detect_test.html

However, I am not sure if I understand properly.

I believe that the design shown with the MAGPIO is used to detect if there is an antenna connected on J1. Is that correct ? (if so, it's not applicable to my design).

https://docs.nordicsemi.com/bundle/nwp_033/page/WP/nwp_033/nwp_033_antenna_detect_magpio.html

The example using GPIO has a similar schematic, but mentions a "test cable".

https://docs.nordicsemi.com/bundle/nwp_033/page/WP/nwp_033/nwp_033_antenna_detect_gpio.html

Could please provide more details on this topic, and let me know if the feature I am willing to acheive is doable or not.

Thanks a lot.

Vincent

[JONATHAN LL]

The documentation you point to is intended more for production tests, so if a device is being tested with "test cable" instead of an antenna there are ways to implement detection methods. 

if there is an antenna connected on J1. Is that correct ?

The connector used on J1 is also a switch that disconnects the remaining circuitry so this is easily detectable. 


The GPIO example is what you would have to use but you would need to make sure that the antenna that is used is DC grounded through its matching circuitry\design. So any antenna that has a inductor to GND should work. But we dont have a list of antennas that we know will work, so you might need to do some testing. 

Regards,
Jonathan