A wireless charging device includes a driver unit configured to generate one of a first AC voltage signal having a first frequency and a second AC voltage signal having a second frequency. Also, the wireless charging device includes a transmitting unit having a first coil and a first capacitor and configured to transmit the first AC voltage signal. Further, the transmitting unit includes a second coil and a second capacitor and configured to transmit the second AC voltage signal. Additionally, the wireless charging device includes a control unit configured to detect a first receiver device operating at the first frequency based on a change in a first voltage in the transmitting unit, and detect a second receiver device operating at the second frequency based on a change in a second voltage in the transmitting unit.