Can I use different number of PCB layers then the EZRadio/EZRadioPro/EZR32/EFR32 reference design PCB layer count without any RF performance degradation?
For custom designs, it is recommended to use the same number of PCB layers as are present in the reference design whenever possible. Deviation from the reference PCB layer count can cause different PCB parasitic capacitances, which can detune the discrete matching network from its optimal form. If a design with a different number of layers than the reference design is necessary, make sure that the distance between the top layer and the first inner layer is similar to that found in the reference design because this distance determines the parasitic capacitance value to ground. Otherwise, detuning of the discrete matching network is possible, and fine tuning of the component values may be required.