Connecting an external Antenna to the Taiyo Yuden EYSHSNZWZ BLE Module using Nordic’s nRF52832 SoC - pin impedances cannot be found?

[anpiri]

I am working on integrating an external antenna with the EYSHSNZWZ BLE module from Taiyo Yuden, which uses Nordic’s nRF52832 SoC. The biggest problem is that I cannot confirm the antenna pins impedances. Can I assume it is 50-ohm impedance, as I believe should be expected with the nRF52832 ? And if so, should I connect the antenna directly to the BLE module's RF pins (Pin 11 for OUT_ANT and Pin 12 for OUT_MOD)?

Thanks in advance for your insights!Taiyo_Yuden-EYSHSNZWZ-datasheet.pdf

[mathiaso]

Hi.

Have you been in contact with Taiyo Yuden as well? They are the ones that should be able to tell you what the connections of these RF pins look like on the inside of the module.

From reading the datasheet you attached, it seems like the OUT_ANT pin is the connection to the module's internal antenna, while OUT_MOD is the connection to the nRF52832's radio.

The ANT pin of the nRF52832 itself does not have an impedance of 50 ohms. If you look at the SoC's reference circuitry, you'll see that there is a matching network for the radio connected to this pin.

However, as it is a module, this is most likely included, and in that case you can assume that the OUT_MOD pin at least is pretty close to 50 ohms. To get an exact number you should ask Taiyo Yuden if they've performed any measurements on the module.

What kind of antenna are you planning to connect to it?

Best regards,
Mathias

[anpiri]

Thank you very much for the response and I apologise for the delay. It is a patch antenna with an edge feed. I am assuming we can directly disconnect the on-board antenna by scratching out the connection and connect it with external wires to the antenna feed and choose one of the 3 ground pins for the antenna ground. If you have any additional thoughts, it would be great to hear from someone with more experience like you.

[mathiaso]

No worries.

Do you have a datasheet for the antenna?

[anpiri]

Unfortunately no, it is something that is being created in house for a research project. All that I know is that there is an edgefeed, and the size of the feedpoint is about 0.5mm thick or slightly smaller.

[mathiaso]

Ok.

If using that antenna instead of the module's internal antenna, it should be possible to connect it to the OUT_MOD pin through whatever matching network your antenna needs.

It could also be an idea to get in touch with Taiyo Yuden to verify what matching network is found between the SoC's ANT pin and the module's OUT_MOD pin.