Abstract: A power amplifier amplifying an input signal is provided, comprising a power amplifier circuit, a bias circuit, and a compensation circuit. The power amplifier circuit has an input impedance responsive to the input signal, and amplifies the input signal to generate an output signal. The bias circuit is coupled to the power amplifier circuit, generates a DC bias signal to the power amplifier so that the power amplifier amplifies the input signal. The compensation circuit is coupled to the power amplifier circuit, provides a compensation impedance responsive to the input signal such that a combination of the input impedance and the compensation impedance is substantially constant regardless of the input signal.

Abstract: A capacitor structure for an integrated circuit. An insulating layer is disposed on a substrate. A first conductive line is embedded in a first level of the insulating layer. A second conductive line is embedded in a second level of the insulating layer lower than the first level and has a projection onto the substrate completely covered by the first conductive line. A third conductive line is embedded in the second level of the insulating layer and separated from the second conductive line by a predetermined space, and has a projection onto the substrate partially covered by the first conductive line. The second conductive line is coupled to the first conductive line by at least one first conductive plug and has a polarity opposite to the third conductive line.

Abstract: A wireless communication device. The wireless communication device comprises first and second programmable frequency dividers, a mixer, a modulator, a phase detector, and a variable controlled oscillator. The first programmable frequency divider divides the frequency of a reference signal by a factor N to generate a modulating signal. The second programmable frequency divider divides the reference signal by a factor M and outputs a frequency-divided signal. The facts N and M are positive integers. The mixer down-converting a transmission signal according the divided signal and outputs a translation-loop signal. The modulator modulates the modulating signal with baseband signals, and outputs a comparison signal. The phase detector detects a phase difference between the comparison signal and the translation-loop signal. The variable controlled oscillator modifies the transmission signals according to an output of the phase detector.

Abstract: A conversion mixer includes a mixing circuit, a duplicating circuit and a loading circuit. The mixing circuit receives a couple of first input signals and a couple of second input signals and mixes the couple of first input signals with the couple of second input signals to output a couple of mixed signals. The duplicating circuit coupled to the mixing circuit receives the couple of mixed signals and duplicates the couple of mixed signals to output a couple of duplicated signals. The loading circuit coupled to the duplicating circuit receives the couple of duplicated signals and outputs a couple of output signals according to the couple of duplicated signals.

Abstract: A variable gain amplifier includes an amplifying circuit and a gain adjusting circuit including the following circuits. A linear exponential transforming circuit transforms a linear controlling signal to output an exponential controlling signal. A voltage buffer circuit is coupled with the linear exponential transforming circuit to receive the exponential controlling signal, outputs a feedback signal to a power transforming circuit, and outputs a voltage controlling signal to control a gain of the amplifying circuit according to the exponential controlling signal and a bias current. A power transforming circuit is coupled with the linear exponential transforming circuit and the voltage buffer circuit to receive the exponential controlling signal and the feedback signal and take two times of a square root of a product of the exponential controlling signal and the feedback signal plus the bias current to output a power signal to the linear exponential transforming circuit.

Abstract: A harmonic-rejection modulation device is provided, which includes a phase splitter, a low pass filter, and a modulator. Based on a square wave, the phase splitter generates a plurality of unfiltered local oscillating signals having phase angles of 0°, 30°, 90°, 120°, 180°, 210°, 270° and 300°, respectively. The low pass filter filters the high frequency components of the unfiltered local oscillating signals to generate a plurality of local oscillating signals having phase angles of 0°, 30°, 90°, 120°, 180°, 210°, 270° and 300°, respectively. The modulator modulates a baseband signal with the local oscillating signals, wherein the third harmonics of the local oscillating signals are eliminated by the modulation process of the modulator. The invention also provides a method of modulating a baseband signal.

Abstract: A mixer of a homodyne RF receiver made from a CMOS process is provided. The mixer comprises a gain stage, a switch stage and a load stage. The gain stage receives a differential-typed RF signal and generating a first gained signal. The switch stage mixes the first gained signal and a LO signal to direct down-convert into a modulated signal. The load stage comprises a first transistor, an impedance element and a second transistor. The first transistor provides a low impedance to permit the modulated signal entering the load stage. The second transistor provides a high impedance to resist signals. The load stage converts the modulated signal to a second gained signal according to a first gain coefficient of the impedance element. The first transistor is a parallel pnp BJT, and the second transistor is a vertical npn bipolar BJT.

Abstract: A semiconductor device (120) is formed in a silicon-on-insulator (SOI) substrate (135). The semiconductor device (120) has a channel region (126) that is controlled by a gate structure (129). The channel region (126) has a doping profile that is essentially uniform where the channel region (126) is under the gate structure (129). This eliminates the parasitic channel region that is common with conventional field effect transistors (FETs) that are formed in SOI substrates. Consequently, the semiconductor device (120) of the present invention does not suffer from the "kink" problem that is common to conventional FET devices.