Abstract: A communication device includes a first connector, a first radio frequency unit, a first transmission line and a first antenna. The first radio frequency (RF) unit is connected to the first connector, the first transmission line has a first terminal and a second terminal, the first terminal of the first transmission line is connected to the first connector, and the first antenna is contacted and electrically coupled to the second terminal of the first transmission line. The first RF unit is configured to generate a first RF signal. The first terminal of the first transmission line is configured to receive the first RF signal, and the first transmission line is configured to transmit the first RF signal from the first terminal of the first transmission line to the second terminal of the first transmission line. The first antenna is configured to send the first RF signal.

Abstract: An antenna device includes an antenna element, a sensing circuit, a matching circuit and an impedance adjusting circuit. The sensing element is used to generate a sensing signal. The matching circuit is coupled to the antenna unit. The impedance adjusting circuit is coupled to the sensing circuit and is capable of turning an impedance of the antenna unit and an impedance of the matching circuit into mismatch according to the sensing signal.

Abstract: A communication device includes an antenna unit, an adjustment unit and a sensing and processing unit. The sensing and processing unit is electrically coupled to the antenna unit and the adjustment unit. The antenna unit is configured to transmit a radio frequency (RF) signal. The adjustment unit is configured to adjust a frequency and a bandwidth of the RF signal. The sensing and processing unit is configured to sense a capacitance, so as to control the adjustment unit to adjust the frequency of the RF signal according to the capacitance, and to control the adjustment unit to adjust the bandwidth of the RF signal according to a system signal.

Abstract: An electronic device includes a display module, an NFC (Near-field Communication) module, a verification module and a control module. The display module is disposed on a first surface of the electronic device. The NFC module includes an antenna unit. The antenna unit is configured to transmit and receive a wireless signal from an outward direction of the first surface. The verification module is disposed on a second surface of the electronic device. The verification module is configured to generate an identification input data according to an operation of a user. The control module is configured to drive the verification module to generate the identification input data when the NFC module receives an identification requirement data, and configured to determine whether the identification input data is valid.