nrf51 Radiated Emissions Fail

RE: nrf51 Radiated Emissions Fail

FormerMember — Mon, 09 Jan 2017 15:34:07 GMT

The matching network is very sensitive. It is therefore important to follow the following:

The distances in the matching network should be exactly the same as in our reference layout. That also includes the distance from ANT1/ANT2 to L1.
There should be ground plane under the entire matching network. Ground as trace will not work. Instead of ground, it will act as a series inductor.

user9513 — Wed, 04 Jan 2017 20:25:55 GMT

there is a print screen of RF part layout: www.dropbox.com/.../antenna_layout.png

FormerMember — Tue, 13 Dec 2016 08:02:15 GMT

The layout of the RF part is very important for correctly suppressing harmonics. Could you upload a picture of the layout?

Dave_couling — Thu, 08 Dec 2016 19:03:25 GMT

There are a few potential causes:

Antenna design - RF is extremely sensitive to dimensions, ground clearance, substrate thickness, transmission line tuning ...etc
Balun: Did you use a discrete balun or chip balun (safer)
HFCLK: Verify that your HF crystal is oscillating at the correct frequency.