Material-discerning sensing by measurement of different points of impedance

摘要

A material-discerning proximity sensor is arranged to include an antenna that is arranged to radiate a radio-frequency signal. A capacitive sensor is arranged to detect a change in capacitance of the capacitive sensor and to receive the radio-frequency signal. An electrical quantity sensor is arranged to detect a change of the received radio-frequency signal and a change of a radio-frequency signal at an output of the at least one band pass filter.