Abstract: A communication device is provided. The communication device comprises a metal back cover electrically connected to a system ground plane; a first antenna unit for generating a first operating frequency band of the communication device; a second antenna unit for generating a second operating frequency band of the communication device. The first antenna unit includes a first signal source electrically connected to a first metal frame via a first matching circuit. The second antenna unit includes a second signal source electrically connected to a second metal frame via a second matching circuit. The first matching circuit and the second matching circuit are configured to adjust bandwidths and frequency ratios of the first operating frequency band and the second operating frequency band.

Abstract: A proximity sensor and a mobile communication device thereof are provided. The mobile communication device includes an antenna structure, a matching circuit, a capacitance sensing circuit and a processing circuit. The matching circuit couples to the antenna structure. The capacitance sensing circuit couples to the matching circuit. The capacitance sensing circuit senses a capacitance variation on the antenna structure via the matching circuit and accordingly generates a proximity sensing signal. The processing circuit is coupled to the capacitance sensing circuit to receive the proximity sensing signal. When a signal level of the proximity sensing signal exceeds a first threshold value, an object is determined approaching, and when the signal level of the proximity sensing signal exceeds a second threshold value, a human body is determines approaching. The first and the second threshold value are different.

Abstract: A communication device is provided. The communication device comprises a metal back cover electrically connected to a system ground plane; a first antenna unit for generating a first operating frequency band of the communication device; a second antenna unit for generating a second operating frequency band of the communication device. The first antenna unit includes a first signal source electrically connected to a first metal frame via a first matching circuit. The second antenna unit includes a second signal source electrically connected to a second metal frame via a second matching circuit. The first matching circuit and the second matching circuit are configured to adjust bandwidths and frequency ratios of the first operating frequency band and the second operating frequency band.

Abstract: A proximity sensor and a mobile communication device thereof are provided. The mobile communication device includes an antenna structure, a matching circuit, a capacitance sensing circuit and a processing circuit. The matching circuit couples to the antenna structure. The capacitance sensing circuit couples to the matching circuit. The capacitance sensing circuit senses a capacitance variation on the antenna structure via the matching circuit and accordingly generates a proximity sensing signal. The processing circuit is coupled to the capacitance sensing circuit to receive the proximity sensing signal. When a signal level of the proximity sensing signal exceeds a first threshold value, an object is determined approaching, and when the signal level of the proximity sensing signal exceeds a second threshold value, a human body is determines approaching. The first and the second threshold value are different.