Slots on ground fillings of multi-layer printed circuit board for suppressing indirect crosstalk between digital clock line and RF signal line in mixed mode mobile systems

In this paper, slots on ground fillings of multi-layer printed circuit board is proposed for suppressing indirect crosstalk between digital clock line and RF signal line in mixed mode mobile systems, and their suppressing efficiency is evaluated by using 2 dimensional finite element method and a series of test vehicles including various slot structures and ground vias on ground fillings. Ground vias mitigate the indirect crosstalk by from 37 dB at 800 MHz to 15 dB at 1200 MHz, and the proposed slots and ground vias on ground fillings suppress the indirect crosstalk by from 57 dB at 800 MHz to 29 dB at 1200 MHz.