The present invention discloses an RF device for a wireless communication device, including a grounding element, an antenna, including a radiating element, a feed-in element, a coupling element, a switch, coupled between the coupling element and the grounding element, for connecting or disconnecting the grounding element to the coupling element, such that the antenna respectively operates in a first frequency band and a second frequency band, and a grounding terminal, for coupling the grounding element, a capacitive sensing element, for sensing an environment capacitance within a specific range through the radiating element, at least one capacitor, for blocking a DC route from the grounding terminal to the grounding element.