Stochastic EMI Noise Model of PCB Layout for Circuit-Level Analysis of System in IoT Applications

In this article, a simple noise model is proposed for analysis of electromagnetic interference (EMI) on printed circuit board (PCB) layout of an electronic device. In Internet of Things (IoT) applications, devices are connected wirelessly and this results in electromagnetic pollution in environment. This may degrade the performance and/or even stop the operation of present devices in the shared setting. Internal and external interferences, due to near- and far-field are modeled as two independent random voltage sources. These sources can be treated as noise source like the thermal noise one in circuit noise analysis including the physical layout and electromagnetic threat. As a quantitative measure of electromagnetic pollution, EMI environment temperature is defined based on aggregation of waves emitted from different wireless device antennas. Also, for the PCBs, a stochastic EMI radiation resistance is defined based on system components' placement and layout. This resistance can be used as an effective measure of interference potential severity for system PCB in an environment. The model is verified by specific designed and fabricated mixed-signal test board. The comparison between analytic model and measurement results shows a moderate accuracy which is acceptable in most predictive electromagnetic compatibility (EMC)/EMI verification. The proposed model is valid up to some GHz for conventional PCB physical parameters.