There is provided a power amplifier and an integrated circuit including the power amplifier. The power amplifier includes a first amplifier configured to amplify a first signal; a phase shifter configured to invert the first signal; and a harmonic sinker connected between an output terminal of the phase shifter and an output terminal of the first amplifier, configured to amplify an output signal of the phase shifter, and configured to have a conduction angle narrower than a conduction angle of the first amplifier.

The present invention provides a card read response method, apparatus, and system, and a signal transceiving device. The method comprises: receiving a carrier signal having a frequency of 125 KHz by using an antenna having a resonance frequency of 13.56 MHz; amplifying the carrier signal, and performing analog-to-digital conversion on the amplified signal to obtain a digital signal; acquiring signal characteristics of the carrier signal according to the digital signal, the signal characteristics comprising at least a frequency and a phase; and encoding response data at the frequency of the carrier signal to obtain an encoded signal, determining an initial phase of the outputted encoded signal according to the phase, and outputting the encoded signal via the antenna so that the encoded signal and the carrier signal are superimposed at the same phase. According to the signal response method, apparatus, and system of the present invention, a small antenna having a resonance frequency of 13.56 MHz can be used to send and receive a signal having a frequency of 125 KHz, so as to meet the demand for device miniaturization.

A transmitter is provided. The transmitter includes a bus system including at least two bus lines. Further, the transmitter includes an envelope tracking circuit coupled to the at least two bus lines, and a plurality of power amplifiers. At least a first one of the plurality of power amplifiers, while in active state, is configured to selectively couple its input to the one of the at least two bus lines which is supplied with a supply voltage or a bias signal by the envelope tracking circuit that is based on an envelope of a first baseband signal related to a first radio frequency signal received by the first one of the plurality of power amplifiers for amplification.

A high-frequency amplifier includes: a carrier amplifier amplifying a first signal; a peak amplifier amplifying a second signal; a first transmission line connected between output terminals of the carrier amplifier and the peak amplifier, and having an electrical length equal to one-quarter wavelength of a center frequency in the predetermined frequency band; a second transmission line connected between one end of the first transmission line and the output terminal of the high-frequency amplifier, and having an electrical length equal to one-quarter wavelength of the center frequency; and an impedance compensation circuit with one end connected to a node between the first transmission line and the second transmission line. At the center frequency, an imaginary part of an impedance during viewing of the impedance compensation circuit from the node is opposite in polarity from an imaginary part of an impedance during viewing of the second transmission line from the node.

An embodiment of a module (e.g., an amplifier module) includes a substrate, a transmission line, and a ground plane height variation structure. The substrate is formed from a plurality of dielectric material layers, and has a mounting surface and a second surface opposite the mounting surface. A plurality of non-overlapping zones is defined at the mounting surface. The transmission line is coupled to the substrate and is located within a first zone of the plurality of non-overlapping zones. The ground plane height variation structure extends from the second surface into the substrate within the first zone. The ground plane height variation structure underlies the transmission line, a portion of the substrate is present between the upper boundary and the transmission line, and the ground plane height variation structure includes a conductive path between an upper boundary of the ground plane height variation structure and the second surface.

An amplification device having a cascode structure includes an amplification circuit including a first transistor and a second transistor, cascode-connected to each other and receiving an operating voltage to amplify an input signal; a first bias circuit generating a first bias voltage and supplying the first bias voltage to the first transistor; and a second bias circuit generating a second bias voltage based on a control voltage and the operating voltage and supplying the second bias voltage to the second transistor.

A radio frequency (RF) power transistor circuit includes a power transistor and a decoupling circuit. The power transistor has a control electrode coupled to an input terminal for receiving an RF input signal, a first current electrode for providing an RF output signal at an output terminal, and a second current electrode coupled to a voltage reference. The decoupling circuit includes a first inductive element, a first resistor, and a first capacitor coupled together in series between the first current electrode of the power transistor and the voltage reference. The decoupling circuit is for dampening a resonance at a frequency lower than an RF frequency.

Apparatus and methods for an improved-efficiency Doherty amplifier are described. The Doherty amplifier may include a two-stage peaking amplifier that transitions from an off state to an on state later and more rapidly than a single-stage peaking amplifier used in a conventional Doherty amplifier. The improved Doherty amplifier may operate at higher gain values than a conventional Doherty amplifier, with no appreciable reduction in signal bandwidth.

A power amplifier includes initial-stage and output-stage amplifier circuits, and initial-stage and output-stage bias circuits. The initial-stage amplifier circuit includes a first high electron mobility transistor having a source electrically connected to a reference potential, and a gate to which a radio-frequency input signal is inputted, and a first heterojunction bipolar transistor having an emitter electrically connected to a drain of the first high electron mobility transistor, a base electrically connected to the reference potential in an alternate-current fashion, and a collector to which direct-current power is supplied and from which a radio-frequency signal is outputted. The output-stage amplifier circuit includes a second heterojunction bipolar transistor having an emitter electrically connected to the reference potential, a base to which the radio-frequency signal outputted from the first heterojunction bipolar transistor is inputted, and a collector to which direct-current power is supplied and from which a radio-frequency output signal is outputted.

Apparatus and methods for quadrature combined Doherty amplifiers are provided herein. In certain embodiments, a separator is used to separate a radio frequency (RF) input signal into a plurality of input signal components that are amplified by a pair of Doherty amplifiers operating in quadrature. Additionally, a combiner is used to combine a plurality of output signal components generated by the pair of Doherty amplifiers, thereby generating an RF output signal exhibiting quadrature balancing.