Abstract: The present invention relates to a power divider and a power combiner employing dual band-Composite Right/Left-Handed (CRLH) transmission lines. A power divider including an input terminal and two output terminals according to the present invention includes two transmission lines each having two terminals connected to the input terminal and the output terminals, respectively, and two short-stubs having one terminals connected to the output terminals, respectively, and the other terminals connected to grounds. The transmission line may employ a first dual band-CRLH transmission line having a double value of a termination impedance, which is substantially connected to the output terminal, as a characteristic impedance, and the short-stub may employ a second dual band-CRLH transmission line, which has substantially the same value as that of the termination impedance as a characteristic impedance.

Abstract: The present invention provides an RF switch, including a diode adapted to operate as a switch when a control current is applied thereto, a first CRLH transmission line of a ? degree phase, which provides one signal transfer path from a terminal 1 to a terminal 2 when the diode is shorted due to application of a control current, and a second CRLH transmission line of a ?-180 degree phase, which has a 180 degree phase difference from that of the first CRLH transmission line and provides the other signal transfer path from the terminal 1 to the terminal 2. The present invention provides an RF switch having a broad-band characteristic by employing a CRLH transmission line. More specifically, the present invention provides a ring-shaped RF switch, which has a broad-band characteristic and can also be miniaturized at a low frequency band, by employing a CRLH transmission line having a 180 degree phase difference in a broad band.

Abstract: The invention relates to built-in antenna. Specifically, a multi-band built-in antenna having plurality of resonant frequencies and a method for adjusting resonant frequencies are provided, wherein resonant frequencies are able to be adjusted independently without affecting one another, for each resonant frequencies are adjusted separately through separate radiating elements.

Abstract: A single-layer dual-band antenna with circular polarization is disclosed. The antenna includes a first radiator formed on the top surface of a substrate and electrically coupled to a feeding element, and a second radiator formed on the top surface of the substrate, spaced apart from the first radiator by a predetermined distance and electromagnetically coupled with the first radiator. The antenna is thin because it has a single-layer structure. Furthermore, there is no deterioration in the radiation characteristic due to interference between the radiators. Moreover, impedances of the radiators can be independently matched at their frequency bands by adjusting the position of a feed point and the relative position of the radiators.

Abstract: The invention relates to built-in antenna. Specifically, a multi-band built-in antenna having plurality of resonant frequencies and a method for adjusting resonant frequencies are provided, wherein resonant frequencies are able to be adjusted independently without affecting one another, for each resonant frequencies are adjusted separately through separate radiating elements.