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: 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: The present invention relates to a gain control circuit for a low-noise amplifier. A gain control circuit of a 2-stage low-noise amplifier comprising an input stage noise matching circuit, an intermediate impedance matching circuit, a gain control circuit, and an output stage impedance matching circuit, said gain control circuit including: a feedback circuit connected to a transistor of second stage of the 2-stage low-noise amplifier, said feedback circuit detecting the amplified signal through the first stage and the second stage, and feeding the signal back through a switch circuit; and an attenuation circuit for compensating the harmonics of the input signal.

Abstract: A gate voltage control circuit of a power amplifier for reducing the power dissipation by improving the efficiency at an average output power and for enhancing the linearity of the power amplifier at a maximum output power, the gate voltage control circuit comprising an input terminal for receiving an output power signal from a power amplifier; an output power detecting circuit for detecting the output power signal and for converting the detected output power signal to a DC voltage signal; a voltage dividing circuit comprising at least two resistors for dividing a voltage difference between the DC voltage signal and a negative voltage in a ratio of resistances of the resistors; and an output terminal for supplying the divided voltage as a gate voltage control signal.