nRF52 DK bluetooth radiation diagram

[Jose Costa]

Hi,

I know that this question was asked before, but I can't find a complete/recent answer.

We are trying to use nrf52 DK board to perform bluetooth localization. In our tests we found that there are significant signal changes (more than 10 db) by changing board orientation.

I know that there is a monopole antenna on the PCB, but I could not find real (i.e. not theorical) radiation diagram.

Is there any radiation diagram available so that we can better understand the problem?

Do you recommend to connect an external antenna for better peformance when doing bluetooth localization?

Any help is very much appreciated!

Thanks!

José Costa

[Andreas]

Hi José,

 

There has been some simple characterization done: nRF52_DK.zip

 

This should serve as an indication only, when mounted in your setup, any differences in mounting/setup or close proximity will change the radiation pattern. As you can see from this there are some angles where the signal strength is close to or more than 10 dB.

 

Using an external antenna will probably remove this as a problem. The system will still be subject to reflections and changes in the channel though, and this might cause just as much variation to the signal strength.

 

Best regards,

Andreas

[Jose Costa]

Hi Andreas,

Thanks for your reply.

Can you point/recommend what external antennas can be used?

Do I need to deactivate the PCB antenna in order to use an external one?

Best Regards,

José Costa

[Andreas]

Hi Jose,

 

I can not recommend any antennas as I do not know what kind of antenna you need. I suggest browsing through what your distributor can provide.

 

When using the DK, the J1 coaxial switch will automatically switch the RF path into a probe cable, and thus the external antenna, once it is inserted. If you use a different solution you will have to disconnect it, yes.

 

Best regards,

Andreas

[Jose Costa]

Hi Andreas,

Regarding the diagrams, can you please tell what are the reference angles, i.e., where angle 0º points to both horizontally and vertically?

Thank you very much!

Best Regards,

José Costa

[Andreas]

Hi José,

 

We do not know this unfortunately.

 

Best regards,

Andreas