Abstract: The present invention discloses an RF front-end circuit for a wireless communication device, which includes an RF terminal coupled to an antenna of the wireless communication device, for receiving or transmitting wireless signals; and a switch for connecting a plurality of processing modules to the RF terminal according to operations of the wireless communication device.

Abstract: A diplexer for receiving and transmitting a first bandwidth signal corresponding to a first central frequency and a second bandwidth signal corresponding to a second central frequency includes a first signal end, a second signal end, a third signal end, a first impedance unit, a second impedance unit and a third impedance unit. The first impedance unit forms an impedance match with the third impedance unit when the third signal end receives or transmits the first bandwidth signal, and forms a high impedance unit when the third signal end receives or transmits the second bandwidth signal. The second impedance unit forms an impedance match with the third impedance unit when the third signal end receives or transmits the second bandwidth signal, and forms a high impedance unit when the third signal end receives or transmits the first bandwidth signal.

Abstract: A second-order band-pass filter for generating at least two transmission zeros includes a first signal terminal, a second signal terminal, a first transmission line resonator, a second transmission line resonator and an impedance inverter. The first transmission line resonator and the second transmission line resonator are symmetric to each other and coupled to the first signal terminal and the second signal terminal, which are formed by bending two quarter-wavelength open stubs and have an open circuit gap between the two terminals. The impedance inverter includes an inductor, a first micro strip line and a second micro strip line. The first micro strip line and the second micro strip line are symmetric to each other, and are coupled to the first signal terminal and the second signal terminal and coupled to a ground through the inductor, respectively.

Abstract: A dual-band antenna is disclosed and used for receiving or transmitting a first frequency band signal corresponding to a first central frequency and a second frequency band signal corresponding to a second central frequency. The dual-band antenna includes a first radiator, a feed line, a second radiator, and two parallel substrates each of which a grounding plane is installed on. The first and second radiators are respectively installed on the substrates and spatially overlap to each other in part. The first radiator receives and transmits the first and second frequency band signals and includes a first metal strip, having a plurality of bends, and a second metal strip. The second metal strip and the feed line are coupled to the first metal strip. The second radiator is used for enhancing the efficiency of receiving the second frequency band signal for the first radiator.

Abstract: A second-order band-pass filter for generating at least two transmission zeros includes a first signal terminal, a second signal terminal, a first transmission line resonator, a second transmission line resonator and an impedance inverter. The first transmission line resonator and the second transmission line resonator are symmetric to each other and coupled to the first signal terminal and the second signal terminal, which are formed by bending two quarter-wavelength open stubs and have an open circuit gap between the two terminals. The impedance inverter includes an inductor, a first micro strip line and a second micro strip line. The first micro strip line and the second micro strip line are symmetric to each other, and are coupled to the first signal terminal and the second signal terminal and coupled to a ground through the inductor, respectively.

Abstract: A diplexer for receiving and transmitting a first bandwidth signal corresponding to a first central frequency and a second bandwidth signal corresponding to a second central frequency includes a first signal end, a second signal end, a third signal end, a first impedance unit, a second impedance unit and a third impedance unit. The first impedance unit forms an impedance match with the third impedance unit when the third signal end receives or transmits the first bandwidth signal, and forms a high impedance unit when the third signal end receives or transmits the second bandwidth signal. The second impedance unit forms an impedance match with the third impedance unit when the third signal end receives or transmits the second bandwidth signal, and forms a high impedance unit when the third signal end receives or transmits the first bandwidth signal.