PCB Noise Radiation

Model

Based on [1], SEMCAD X is applied to investigate methods to reduce the switching noise radiation common to digital curcuit PCB boards. Moating effects are tested by evaluating reference, isolated and bridge conditions.

Simulations

A 20 mV noise source injects noise between Vcc and curcuit ground layers. Current distributions, coupling accross the moat and EMI levels are recorded.

Results

S21 coupling from the source to a point outside the moat region is recorded across the bandwidth. Good agreement with other simulation and measurement results is obtained. In addition surface current distributions and emission leveles are extracted.

[1] Tzong-Lin Wu et. al.; Numerical and Experimental Investigation of Radiation Caused by Switching Noise on the Partitioned DC Reference Planes of High Speed Digital PCB; IEEE EMC Vol. 46, No. 1, Feb 2004