nRF52 PCB design - chip antenna required?

[Ronnie Tango]

Hi,

Apologies if this is an obvious question, but I haven't been able to establish from previous questions or the data sheet whether it is necessary to use an external chip antenna when designing boards with the nRF52? Or is the small rectangular pad in the reference design marked "RF" (toward the bottom right corner) a PCB antenna in itself?

Thanks!

[Einar Thorsrud]

You can use a PCB antenna. The nRF52-DK has a PCB antenna on the top layer, this is on the part of the board that sticks out a bit on the right side, with the Nordic logo printed on it. You can see this in the reference layout.

[Ronnie Tango]

Great, thanks. Also, to check I've understood the info in other posts - if using a chip antenna, it is necessary to include a matching (Pi) network in addition to the RF choke network (L1 and C3), in order to match the antenna to 50 Ohms?

Is the physical placement of the Pi-network important? Should it be immediately after L1, or after the rectangular pad marked "RF" in the reference design?