Abstract: A wireless power transfer system includes a wireless power transmitter and a wireless power receiver. The wireless power receiver includes: a receiver resonator for wirelessly receiving power from the wireless power transmitter through resonant inductive coupling to generate an AC induced voltage; an AC-to-DC converter having a first input terminal and a second input terminal that are connected to the receiver resonator for receiving the AC induced voltage therefrom, and converting the AC induced voltage into a DC converted voltage; and a power storage element connected to the first and second input terminals of the AC-to-DC converter.

Abstract: A radio-frequency (RF) transceiver front-end circuit includes an antenna, a power amplifier, a low-noise amplifier, a first switch unit and a second switch unit. The power amplifier is connected to a transmitting unit and the antenna to form a transmission path. The low-noise amplifier is connected to a receiving unit and the antenna to form a reception path. The transmission path and the reception path selectively do not include a ?/4 transmission line connected to the antenna. The RF transceiver front-end circuit has a receiving state and a transmitting state. In the receiving state, the first switch unit is controlled and causes the transmission path to have high impedance. In the transmitting state, the second switch unit is controlled and causes the reception path to have high impedance.

Abstract: A radio-frequency/direct-current (RF/DC) converter is operable to receive a high-frequency and high-power RF signal and convert to a DC power. The RF/DC converter includes a first field-effect transistor (FET), a second FET, a third FET and a sixth FET that are cross-coupled. Sources of the first FET and the second FET are connected to an RF signal receiving end. Sources of the third FET and the fourth FET are connected to a potential reference end. The RF/DC converter further includes a fifth FET and a sixth FET connected subsequently to the first FET, the second FET, the third FET and the fourth.

Abstract: A down-conversion mixer includes a trans conductance circuit and a mixing circuit. The transconductance circuit includes: first and second transconductance units cooperatively converting a differential input voltage signal pair into a differential input current signal pair; and an inductor coupled between the first and second transconductance units. The mixing circuit is coupled to a common node of the first trans conductance unit and the inductor and to a common node of the second transconductance unit and the inductor for receiving the differential input current signal pair therefrom, and mixes the differential input current signal pair with a differential oscillatory voltage signal pair to generate a differential mixed voltage signal pair.

Abstract: A radio-frequency (RF) transceiver front-end circuit includes an antenna, a power amplifier, a low-noise amplifier, a first switch unit and a second switch unit. The power amplifier is connected to a transmitting unit and the antenna to form a transmission path. The low-noise amplifier is connected to a receiving unit and the antenna to form a reception path. The transmission path and the reception path selectively do not include a ?/4 transmission line connected to the antenna. The RF transceiver front-end circuit has a receiving state and a transmitting state. In the receiving state, the first switch unit is controlled and causes the transmission path to have high impedance. In the transmitting state, the second switch unit is controlled and causes the reception path to have high impedance.

Abstract: A voltage-controlled oscillator includes an oscillation generator, two inductors and two amplifiers. The oscillation generator generates two oscillation voltage signals based on a control voltage. Each inductor receives a respective oscillation voltage signal, and provides a respective input voltage signal. Each amplifier generates a respective current signal based on a respective input voltage signal. When one of the current signals has a magnitude that varies according to a magnitude of the respective input voltage signal, the other of the current signals has a constant magnitude. The current signals are combined into an output current signal at a common node of the amplifiers.

Abstract: A down-conversion mixer includes a trans conductance circuit and a mixing circuit. The transconductance circuit includes: first and second transconductance units cooperatively converting a differential input voltage signal pair into a differential input current signal pair; and an inductor coupled between the first and second transconductance units. The mixing circuit is coupled to a common node of the first trans conductance unit and the inductor and to a common node of the second transconductance unit and the inductor for receiving the differential input current signal pair therefrom, and mixes the differential input current signal pair with a differential oscillatory voltage signal pair to generate a differential mixed voltage signal pair.

Abstract: A multi-order wave voltage controlled oscillator (VCO) includes a power impedance matching unit, a signal transmitting unit, a harmonic wave eliminating unit and an oscillation frequency adjusting unit. The power impedance matching unit includes an input end, an output end and a first transmission line between the input end and the output end. The first transmission line is a ¼-wavelength transmission line based on a wavelength of an output harmonic wave. The signal transmitting unit includes multiple upper inductor electrically connected to the output end and multiple lower inductors electrically connected to a ground end. The harmonic wave eliminating unit includes multiple transistors electrically connected to the signal transmitting unit and each having a drain electrically connected to a gate of the adjacent transistor to form a multi-order ring loop. The oscillation frequency adjusting unit includes multiple varactors.

Abstract: An injection locked frequency divider includes a mixer circuit and a filter circuit. The mixer circuit includes two mixer units and two inductors. The mixer units mix a differential input voltage signal with a reference signal to output a differential current signal. The inductors cooperatively receive the differential current signal from the mixer units. The filter circuit is connected to the inductors, and filters the differential current signal to output a filtered differential voltage signal.

Abstract: A digital modulating device includes an oscillator that generates an oscillation signal, and a frequency doubling modulator that includes: a single-ended to differential converter converting the oscillation signal into two periodic signals; two inductors respectively receiving the periodic signals and respectively providing two input signals; a switching circuit; and two amplifier circuits. When the switching circuit operates in a first state, the amplifier circuits respectively amplify the input signals to respectively generate two amplified signals that are combined into a combined signal at a common node thereof. When the switching circuit operates in a second state, the amplifier circuits do not perform amplification.

Abstract: A mixer includes a transconductance circuit and a mixing circuit. The transconductance circuit includes a capacitor and first and second transconductance modules. The first transconductance module converts a single-ended to-be-shifted voltage signal at a first terminal of the capacitor into a first input current signal. The second transconductance module converts a voltage signal at a second terminal of the capacitor into a second input current signal that cooperates with the first input current signal to constitute a differential input current signal pair. The mixing circuit mixes the differential input current signal pair with a differential oscillatory voltage signal pair to generate a differential mixed voltage signal pair.

Abstract: An RF transceiver front-end circuit includes an antenna, a first transceiving switch, a reception processing unit, a transmission processing unit and a transmission unit. The reception processing unit includes a low-noise amplifier, a first variable gain amplifier at a back-end circuit of the low-noise amplifier, and a first phase shifter at a back-end circuit of the first variable gain amplifier, wherein a phase of the first variable gain amplifier is constant. The transmission processing unit includes a power amplifier, a second phase shifter at a front-end circuit of the power amplifier, and a second variable gain amplifier at a front-end circuit of the second phase shifter, wherein a phase of the second variable gain amplifier is constant. The transmission unit includes a transmission line and a plurality of passive phase adjustors controlled to change a phase shifting angle of a signal on the transmission line.

Abstract: A voltage-controlled oscillator includes a first transistor, a second transistor, a first center-tapped inductor, two first varactors, a second center-tapped inductor and two second varactors. The first and second transistors cooperatively forma cross-connected pair. The first center-tapped inductor and the first varactors cooperatively form a first LC tank. The second center-tapped inductor and the second varactors cooperatively forma second LC tank. The cross-connected pair is connected between the first and second LC tanks. The first and second center-tapped inductors are mutual-inductively coupled to each other. An oscillation signal pair is provided between the first LC tank and the cross-connected pair.

Abstract: A voltage controlled oscillator includes a resonance unit, coupling unit and source degeneration unit. The resonance unit includes two first inductors and two first variable capacitors. The first inductor is electrically connected to the first variable capacitor. The coupling unit includes a first transistor and a second transistor. Power supply input terminals of the first and second transistors are electrically connected to the resonance unit. The source degeneration unit includes two adjustable inductors, two fourth inductors and two second variable capacitors. The adjustable inductors are connected to power supply output terminals of the first and second transistors, respectively.

Abstract: A power converter includes a power conversion circuit converting an input voltage into an output voltage, and a feedback control circuit including a voltage detector module generating a feedback signal having a signal frequency proportional to a magnitude of the output voltage, a phase detector module generating counting-up and counting-down signals based on the signal frequency and a reference frequency, and a control input generator module controlling the power conversion circuit to adjust the output voltage based on the counting-up and counting-down signals. The logic levels of the counting-up and counting-down signals are maintained until a relative relationship between the signal frequency and the reference frequency changes.

Abstract: A multi-way power amplifier circuit includes two baluns and a number (2×N) of differential power amplifiers, where N?2. Each balun generates a number (N) of corresponding differential intermediate signal pairs based on a respective to-be-amplified signal. Each differential power amplifier generates a respective differential amplified signal pair based on a respective differential intermediate signal pair. One of the baluns includes: a first transmission line and a second transmission line connected to each other; a number (N) of third transmission lines electromagnetically coupled to the first transmission line; and a number (N) of fourth transmission lines electromagnetically coupled to the second transmission line.

Abstract: An RF power amplifier circuit includes a power divider, multiple power amplification circuits and a power combiner that cooperatively perform power amplification on an RF input signal so as to output an RF output signal, and an impedance conversion circuit that has a circuit terminal coupled to one of the power divider and the power combiner which has a microstrip structure, and that is configured such that a conversion impedance, which is an impedance seen into the impedance conversion circuit from the circuit terminal, matches an impedance seen into the power divider or the power combiner from the circuit terminal. The microstrip structure has a physical length associated with the conversion impedance.

Abstract: A radio frequency (RF) power amplifier includes an amplifying stage that includes an amplifying module, an input module and a feedback module. The amplifying module receives an RF to-be-amplified signal, and performs power amplification on the RF to-be-amplified signal to generate an RF output signal. The input module receives an RF input signal. The feedback module receives the RF output signal, cooperates with the input module to provide the RF to-be-amplified signal based on the RF input and output signals, and cooperates with the amplifying module to forma positive feedback loop that provides a loop gain which is less than one.

Abstract: A voltage controlled oscillator includes a resonance unit, coupling unit and source degeneration unit. The resonance unit includes two first inductors and two first variable capacitors. The first inductor is electrically connected to the first variable capacitor. The coupling unit includes a first transistor and a second transistor. Power supply input terminals of the first and second transistors are electrically connected to the resonance unit. The source degeneration unit includes two adjustable inductors, two fourth inductors and two second variable capacitors. The adjustable inductors are connected to power supply output terminals of the first and second transistors, respectively.

Abstract: A down-conversion mixer includes a transconductance unit, a resonant unit and a mixing unit. The transconductance unit converts a differential input voltage signal pair into a differential input current signal pair. The resonant unit provides a negative resistance and a differential auxiliary current signal pair. The mixing unit mixes a combination of the differential input current signal pair and the differential auxiliary current signal pair with a differential oscillatory voltage signal pair to generate a differential mixed voltage signal pair.