A dual-band MMIC power amplifier and method of operation to amplify frequencies in different RF bands while only requiring input drive signals at frequencies f.sub.1 and f.sub.2 in a narrow RF input band. This allows for the use of a conventional narrowband RF IC to drive the MMIC and does not require additional circuitry (e.g., a LO) on the MMIC power amplifier. The matching network of the last amplification stage is modified to pass f.sub.1 (or a harmonic thereof), reflect f.sub.2, pass a P.sup.th harmonic of f.sub.2 where P is 2 or 3 and to reflect any unused 1.sup.st, 2.sup.nd or 3.sup.rd order harmonics of f.sub.1 or f.sub.2 back into the MMIC. In response to an input signal at f.sub.1, the MMIC power amplifier amplifies and outputs a signal at f.sub.1 (or a harmonic thereof). In response to an input signal at f.sub.2 at sufficient RF power, the last amplification stage operates in compression such that the MMIC power amplifier generates the harmonics, selects the P.sup.th harmonic and outputs an amplified RF signal at P*f.sub.2.

Provided are a matching network, an antenna circuit and an electronic device. The matching network includes a first inductor, a second inductor, and a third inductor, the first inductor having two ends serving as a pair of output terminals, the second inductor having two ends serving as a first pair of input terminals, and the third inductor having two ends serving as a second pair of input terminals, where a first coupling coefficient between the first inductor and the second inductor is greater than a second coupling coefficient between the first inductor and the third inductor. According to the matching network, the matching network can present a rather large resistance value conversion ratio even with a rather small area taken by inductors, the circuit design can be more flexible, and the signal interference can be lowered.

Provided is a method of processing an input signal of an amplifier in an electronic device, the method including obtaining a pre-distorter configured to pre-distort an input signal of the amplifier by using a pretrained neural network model to pre-distort the input signal of the amplifier based on signals input to and output from the amplifier, which are obtained while the amplifier operates in a plurality of different environments, and a plurality of pieces of environmental information corresponding to the plurality of different environments, obtaining an input signal for the amplifier, obtaining information about an environment of the amplifier, pre-distorting the input signal by using the pre-distorter based on the obtained environmental information to prevent an output signal in response to the input signal to be processed by the amplifier from being distorted, and inputting the pre-distorted input signal to the amplifier.

A power amplifier circuit is provided that includes a transmission circuit, a control circuit, a first terminal, and a second terminal. The transmission circuit includes an amplifier element that amplifies power of a radio frequency signal. The control circuit controls the transmission circuit. The first terminal receives a serial data signal that is based on a serial data standard. The second terminal receives a digital signal different from the serial data signal. The control circuit then controls the transmission circuit in response to the digital signal received from the second terminal.

A high-frequency amplifier includes: a common-source transistor that has gate fingers, drain fingers, and source fingers, amplifies a signal applied to each of the gate fingers as a signal to be amplified, and outputs an amplified signal from each of the drain fingers; a common-gate transistor that has source fingers connected to the drain fingers of the common-source transistor, drain fingers, and gate fingers, and amplifies the amplified signal output from each of the drain fingers of the common-source transistor; a gate bus bar connected to the gate fingers of the common-gate transistor; and capacitors each having a first end connected to the gate bus bar and a second end grounded: wherein the capacitors are arranged at respective positions where impedances obtained by looking toward the respective capacitors from the respective gate fingers of the common-gate transistor are equal to each other.

A system and method which includes receiving an input signal having an envelope and generating an envelope detection signal corresponding to the envelope. A bias current provided to an amplifier circuit is adjusted based upon the envelope detection signal, the amplifier circuit including an amplifier and a transformer. The transformer is configured to establish a magnetically coupled feedback loop from an output of the amplifier to an input of the amplifier. An output signal is provided, by the amplifier circuit, in response to the input signal.

Apparatus and methods for load modulated power amplifiers are provided. In certain embodiments, a load modulated power amplifier system includes a power amplifier that receives a radio frequency signal at an input and provides an amplified radio frequency signal at an output, and a controllable load impedance coupled to the output of the power amplifier. The controllable load impedance receives an envelope signal that changes in relation to an envelope of the radio frequency signal, and the envelope signal is operable to control an impedance of the controllable load impedance to modulate a load at the output of the power amplifier.

Circuits and methods for improving IC yield during automated test equipment (ATE) calibration of circuit designs which require I.sub.DD calibration and use a closed feedback bias circuit, such as amplifier circuits. The circuit designs include bias branch/active circuit architectures where the active circuit includes one or more active devices. An example first embodiment uses an on-chip calibration switch between the on-chip grounds of a bias network and an active circuit comprising an amplifier. During calibration of the active circuit by the ATE, the calibration switch is closed, and after completion of calibration, the calibration switch is opened. An example second embodiment utilizes an active on-chip feedback loop calibration circuit to equalize voltages between the on-chip grounds of a bias network and an active circuit comprising an amplifier during calibration of the active circuit. Both embodiments mitigate or overcome miscalibration of active circuit current settings resulting from ATE test probe resistance.

A class-D RF power amplifier (PA) architecture with duty cycle control has improved power efficiency while suppressing even-order harmonics. An inductor and capacitor (LC) low pass filter (LPF) can also be integrated on-chip to further suppress harmonics and provide impedance transformation between the PA and load. This eases the design for customers and reduce their bill of materials cost. The LPF can also match the PA to the load impedance to improve efficiency. The harmonic levels can also be controlled by adjusting the duty cycle of the PA output.

Power amplifier systems with DC current reuse across stages are disclosed. In certain embodiments, a mobile device includes a transceiver configured to generate a first radio frequency input signal, and a front end system. The front end system includes a first power amplifier stage configured to amplify the first radio frequency input signal to generate a first radio frequency output signal, and a second power amplifier stage configured to amplify a second radio frequency input signal to generate a second radio frequency output signal. The first power amplifier stage and the second power amplifier stage are electrically connected in a first stack between a first power high supply voltage and a power low supply voltage and configured to operate with a shared DC bias current.