Is there a way to create a dual antenna PCB layout (SMA + PCB antenna) ?

[didier]

Hi,

  We have successfully created a PCB layout with a PCB antenna following the reference schematic provided by the nrf8001 datasheet. We tested and it is working fine. However we would like to add an option to the user to insert an antenna to increase the BLE range but still letting the PCB antenna there.

  Is this feasible, is there any dual antenna (SMA + PCB antenna) reference schematic so we could analyse and base our design on? Or should I just create a support ticket for Nordic technical support staff to help us out on this issue?

Regards, 

[Kaja]

Hi,

our DK's uses this feature; 
(nRF52840 DK)

Just add a connector with a switch on the RF line, so that when you connect the external antenna, you disconnect the connection to the on board antenna. 



We use this type on the DK's: https://www.digikey.no/product-detail/no/murata-electronics/MM8130-2600RA2/490-4981-1-ND/1775925

Best regards,
Kaja

[didier]

Thanks Kaja!

  As far I understood this connector will require a cable for a SMA type antenna. My design ideia is to use a SMA crimp connector in the PCB itself just like this one: http://www.annxin.com/products/glod-sma-female-4-pin-crimp-connector-edge-pcb-mount/

  Do you think is feasible?

Best Regards,

[Kaja]

Hi,

okay, but then you need to have a switch or a 0 Ohm resistor on both RF path, so that you can chose what antenna you want to use. 

I don't know if there are a SMA connector with a switch on the marked... maybe something like this: http://www.aliner.com.tw/RF_Switch.aspx

Best regards,
Kaja

[didier]

Hi Kaja,

  From what I understood, this means that I can't have both of them working at the same time, correct? Is it possible to put a jumper instead of a switch to change between antennas?

  If only one can work at the same time, our design will require the SMA connector so users can attach an antenna to it. To get support on this design I'll have to create a support ticket, correct?

Best regards,

[Kaja]

Hi,

yes, a jumper or a 0 Ohm resistor, just make sure that they shear one pad, so that you don't get a shunt on your RF path. 

You can create a ticket yes, private or public, based on if you want the design files to be public or not. 

Best regards,
Kaja