A foreign object detection method and apparatus for performing same. A wireless power transmitter has a matching network and transmit coil. The method includes, stimulating the transmit coil with electrical signals at a plurality of frequencies, measuring a response of the transmit coil to the electrical signals, determining a quality factor and/or resonant frequency of the transmit coil based upon the measured response, and analyzing the quality factor and/or resonant frequency to determine whether a foreign object is coupled to an electromagnetic field generated by the transmit coil.