Teaching near field coupling with PCB layout

A novel EMC laboratory experiment to illustrate the effects of near field coupling is presented. Using two separate printed circuit boards (PCB), one being the emitter PCB with a digital oscillator circuit driving current in a loop, and the other being a receptor PCB having passive loop of identical size. An LED on board the receptor PCB gives visual feedback on the intensity of the coupling. The experiment helps to illustrates the effect of implementing several design rules. The effects are analysed using equivalent circuits to explain coupling. Lessons learnt from this experiment can be readily applicable to multi-layer PCB design.