Patent ID: 8723749

Claim:
A radio-frequency (RF) device for a wireless communication device, comprising: a grounding element, for providing grounding; an antenna, comprising: a radiating element; a feed-in element, coupled to the radiating element, for transmitting an RF signal through the radiating element; a coupling element, for coupling the radiating 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, electrically connected to the radiating element of the antenna, for sensing an environment capacitance within a specific range through the radiating element; at least one capacitor, electrically connected between the grounding terminal and the grounding element, for blocking a direct-current (DC) route from the grounding terminal to the grounding element.