*Antenna Systems*

**Figure 8.** *FOD to a chew-gum aluminium wrap which have begun a fire.*

Cross-talking or localised charging happens if the transmitter is much larger than the receiver. The magnetic flux path should only occur between the transmitter coil and the receiver coil. Only the transmitter coil that is closest to the receiver is powered on with others around in standby mode. This type of WPT are mostly used on dynamic EV charging applications where power consumption by each transmitter coil can be monitored to roughly identify the position of the receiving coil.

Not-alignment between primary-secondary coil is usually measured in degrees, from perfectly aligned 0*<sup>o</sup>* up to the coils orthogonally each other. Beyond the same size mentioned previously, another solution could be adopting a movable transmitter coil to align it at the position of the receiving coil which is detected through certain sensors. The transmitter coil will be moved to the place right beneath the receiving coil. This solution has a great potential in the stationary EV charging because precisely adjusting the position of vehicle is relatively difficult especially when the receiving coil is very small.

The foreign objects detection (FOD) near the transmitter coil or pad cause safety issue because of the eddy current created inside metallic objects. An increased temperature can be observed in daily metal objects such as coins, keys and metallic packaging materials. In **Figure 8** is shown the effect of a commercial chew-gum in its typical aluminium wrap. Eddy currents have increased temperature and a begin of fire have started.
