Abstract: Provided is a voltage-controlled oscillator (VCO) using an LC resonator circuit which includes a first resonance circuit in which two serially connected varactor diodes and an inductor are connected in parallel, a second resonance circuit in which one or more inductor L1 and one or more capacitor C1 are connected in parallel, the second resonance circuit being serially connected to a port of the first resonance circuit, and a third resonance circuit in which one or more inductor L2 and one or more capacitor C2 are connected in parallel, the third resonance circuit being serially connected to the other port of the first resonance circuit.

Abstract: An antenna device for a portable terminal, which allows a whip antenna and helical antenna of a terminal to be retracted and withdrawn along an extension from the terminal, while not causing them to protrude out of the terminal. The antenna device provided with a whip antenna and helical antenna further includes an antenna housing disposed at a desired position in the main body, which permits the whip antenna to be retracted and withdrawn through the helical antenna, while causing the helical antenna to be withdrawn along an extension from the main body at the same time, and permits the helical antenna to be retracted, so that it can be inserted into the main body; and a housing coupling portion disposed in the main body for supporting the antenna housing.

Abstract: Provided is a voltage-controlled oscillator (VCO) using an LC resonator circuit which includes a first resonance circuit in which two serially connected varactor diodes and an inductor are connected in parallel, a second resonance circuit in which one or more inductor L1 and one or more capacitor C1 are connected in parallel, the second resonance circuit being serially connected to a port of the first resonance circuit, and a third resonance circuit in which one or more inductor L2 and one or more capacitor C2 are connected in parallel, the third resonance circuit being serially connected to the other port of the first resonance circuit.

Abstract: An antenna device for a portable terminal, which allows a whip antenna and helical antenna of a terminal to be retracted and withdrawn along an extension from the terminal, while not causing them to protrude out of the terminal. The antenna device provided with a whip antenna and helical antenna further includes an antenna housing disposed at a desired position in the main body, which permits the whip antenna to be retracted and withdrawn through the helical antenna, while causing the helical antenna to be withdrawn along an extension from the main body at the same time, and permits the helical antenna to be retracted, so that it can be inserted into the main body; and a housing coupling portion disposed in the main body for supporting the antenna housing.

Abstract: An antenna device for a portable terminal, including a support pivotably disposed on the terminal, which is unfolded from the terminal and rests at an angle for supporting the terminal on a planar surface; and an antenna module disposed on the support. The antenna device is disposed on the support or is formed by the support itself, and receives signals through the support when a user wants to enjoy DMB service. The support is provided in the terminal to avoid a need of a separate portable antenna for DMB service, thereby improving convenience of use. Further, when the support is unfolded from the terminal, the terminal can be placed on the planar surface at a convenient angle for viewing, so that users can enjoy DMB service from a comfortable position.