Power and ground planes under balunhttps://devzone.nordicsemi.com/f/nordic-q-a/4391/power-and-ground-planes-under-balunHi I am developing for the nRF51822 a 4 layer print with a power and a ground plane in the inner layers. I will be using a balun from Johanson Technology (2450BM14E0003) with the Nordic PCB antenna (from the USB dongle). The product specificationen-USTelligent Community 13Wed, 12 Nov 2014 07:30:32 GMTRE: Power and ground planes under balunhttps://devzone.nordicsemi.com/thread/15590?ContentTypeID=1Wed, 12 Nov 2014 07:30:32 GMT137ad170-7792-4731-bb38-c0d22fbe4515:07d9b560-f59e-4d0e-81e3-c63b96251ba1Daniel<p>Thank you very much! This explains my question.</p><div style="clear:both;"></div>RE: Power and ground planes under balunhttps://devzone.nordicsemi.com/thread/15589?ContentTypeID=1Tue, 11 Nov 2014 09:37:34 GMT137ad170-7792-4731-bb38-c0d22fbe4515:e554ced2-1ba9-40a8-8253-599f9c794b35Asbj&#248;rn<p>For the balun it&#39;s different and you can have inner layer under the balun, but we would strongly recommend you to have the inner ground plane at least closest to the balun to prevent coupling to the power plane.</p> <p>The keep out area is for discrete matching network as they are put together by multiple components, they are more susceptible to stray capacitance as you have components from various manufacturers.</p><div style="clear:both;"></div>