We have one of our products failing a certification test because the radiated RF energy at 168 MHz is too high. This 168 MHz being the MCU clock frequency. The treshold is only exceeded by 0.8 dB so that's really annoying. We could solve this by placing a metal hood over the MCU but that requires quite a bit of redoing the PCB-layout and it seems a bit of overkill to solve just this 0.8 dB..... I wonder if there are any other tips and tricks that we could use to bring the clock frequency RF leakage down?
(note: we are already using a multilayer PCB of which two layers are groundplanes, so nothing to gain there)
