An amplifier includes a transistor chip including a plurality of transistor cells, a gate pad, and a drain pad, a matching substrate having a surface on which a metal pattern is formed, a terminal with a width larger than a width of the transistor chip and than a width of the matching substrate, a plurality of terminal wires connecting the terminal to the metal pattern, and a plurality of chip wires connecting the metal pattern to the transistor chip. Inter-wire distances of portions of the plurality of terminal wires connected to the metal pattern are larger than inter-wire distances between portions of the plurality of terminal wires connected to the terminal.

Apparatus and methods for true power detection are provided herein. In certain embodiments, a power amplifier system includes an antenna, a directional coupler, and a power amplifier electrically connected to the antenna by way of a through line of the directional coupler. The power amplifier system further includes a combiner that combines a first coupled signal from a first end of the directional coupler's coupled line with a second coupled signal from a second end of the directional coupler's coupled line.

Apparatus and methods for true power detection are provided herein. In certain embodiments, a power amplifier system includes an antenna, a directional coupler, and a power amplifier electrically connected to the antenna by way of a through line of the directional coupler. The power amplifier system further includes a combiner that combines a first coupled signal from a first end of the directional coupler's coupled line with a second coupled signal from a second end of the directional coupler's coupled line.

An amplifier circuit includes an input terminal, an output terminal, a transistor provided in between the input terminal and the output terminal, and a coiled or meandered inductor. The transistor has a gate, a source, and a drain, and of these gate, source, and drain, two terminals are connected to ground terminals that are different from each other. The inductor is connected between the ground terminals to which the foregoing two terminals are connected.

A variable-gain power amplifying technique includes generating, with a network of one or more reactive components included in an oscillator, a first oscillating signal, and outputting, via one or more taps included in the network of the reactive components, a second oscillating signal. The second oscillating signal has a magnitude that is proportional to and less than the first oscillating signal. The power amplifying technique further includes selecting one of the first and second oscillating signals to use for generating a power-amplified output signal, and amplifying the selected one of the first and second oscillating signals to generate the power-amplified output signal.

Apparatus and methods for true power detection are provided herein. In certain embodiments, a power amplifier system includes an antenna, a directional coupler, and a power amplifier electrically connected to the antenna by way of a through line of the directional coupler. The power amplifier system further includes a first switch, a second switch, and a combiner that combines a first coupled signal received from a first end of the directional coupler’s coupled line through the first switch and a second coupled signal received from a second end of the directional coupler’s coupled line through the second switch.

Apparatus and methods for true power detection are provided herein. In certain embodiments, a power amplifier system includes an antenna, a directional coupler, and a power amplifier electrically connected to the antenna by way of a through line of the directional coupler. The power amplifier system further includes a first switch, a second switch, and a combiner that combines a first coupled signal received from a first end of the directional coupler’s coupled line through the first switch and a second coupled signal received from a second end of the directional coupler’s coupled line through the second switch.

Disclosed is a power amplifier system having a main amplifier with an input coupled to a main radio frequency (RF) input and an output connected to a main RF output, wherein the main amplifier exhibits a nonlinear gain characteristic with compression. At least one compression compensating amplifier has a signal input coupled to the common RF input and a signal output coupled to the common RF output.

A control system is configured to control an output power of a power amplifier. The control system is operable to detect when the power amplifier is in first state and responsively provide first additional bias to the power amplifier. The first additional bias assists or enables the power amplifier in increasing the output power. The control system is also operable to detect when the power amplifier is in a second state and responsively provide second additional bias to the power amplifier. The second additional bias assists or enables the power amplifier in increasing the amount of output power.

A low noise amplifier and a method of controlling an amplifier circuit that can enable detection of a fault are provided. The low noise amplifier includes an amplifier circuit. The amplifier circuit includes an amplification transistor configured to amplify a signal input from an input terminal and to output the amplified signal to a first node, a current mirror circuit configured to supply a bias current to the amplification transistor, a resistor provided on a feedback path for feeding an output of the first node back to the input terminal, and a first switch provided on the feedback path and configured to set up or cut off the feedback path. The feedback path is cut off by the first switch when detection of a fault of the amplification transistor is performed.