Device, system and method for detection of a foreign object

A detection device, comprising:

• a detection mat having at least one pair of groups of detection coils, the at least one pair of groups of detection coils including a first group of detection coils having a first impedance value and a second group of detection coils having a second impedance value, wherein the first and second impedance values are dissimilar to one another;
• one or more drive sub-systems operatively coupled to the detection mat and configured to excite at least one pair of groups of detection coils using different voltage signals provided to the first and second groups of detection coils such that the first and second groups of detection coils are driven by corresponding currents having substantially similar magnitude and phase in the absence of a foreign object;
• and
• a comparison sub-system operatively coupled to the detection mat and configured to generate a control signal indicating a presence of the foreign object based on a differential current signal from the at least one pair of groups of detection coils.