A power supply circuit in a wireless communications system includes an envelope tracking modulator coupled to a first power amplifier circuit and a second power amplifier circuit, so that the power supply circuit supplies power to the first power amplifier circuit and the second power amplifier circuit. When a transmit signal output by a processor is within a first bandwidth range, the power supply circuit supplies power to the first power amplifier circuit, and the first power amplifier circuit amplifies power of the transmit signal. When the transmit signal output by the processor meets a second bandwidth range, the power supply circuit supplies power to the second power amplifier circuit, and the second power amplifier circuit amplifies the transmit signal.

A power supply circuit in a wireless communications system includes an envelope tracking modulator coupled to a first power amplifier circuit and a second power amplifier circuit, so that the power supply circuit supplies power to the first power amplifier circuit and the second power amplifier circuit. When a transmit signal output by a processor is within a first bandwidth range, the power supply circuit supplies power to the first power amplifier circuit, and the first power amplifier circuit amplifies power of the transmit signal. When the transmit signal output by the processor meets a second bandwidth range, the power supply circuit supplies power to the second power amplifier circuit, and the second power amplifier circuit amplifies the transmit signal.

An amplifier circuit includes a first amplifier that amplifies a high frequency signal, and a load circuit that changes a load impedance of the first amplifier without being controlled by an external circuit so that a saturation power at a first temperature is higher than a saturation power at a second temperature lower than the first temperature, and an efficiency at the first temperature is lower than an efficiency at the second temperature.

An amplifier circuit includes a first amplifier that amplifies a high frequency signal, and a load circuit that changes a load impedance of the first amplifier without being controlled by an external circuit so that a saturation power at a first temperature is higher than a saturation power at a second temperature lower than the first temperature, and an efficiency at the first temperature is lower than an efficiency at the second temperature.

A tracker module is provided that includes a second substrate that is separate from a first substrate, a tracker component, and a low pass filter. A power amplifier is disposed on or in the first substrate. Moreover, the tracker component supplies a power supply voltage to the power amplifier. The low pass filter is disposed on a path between an output terminal of the tracker component and the power amplifier. The tracker component and the low pass filter are disposed on or in the second substrate.

A tracker module is provided that includes a second substrate that is separate from a first substrate, a tracker component, and a low pass filter. A power amplifier is disposed on or in the first substrate. Moreover, the tracker component supplies a power supply voltage to the power amplifier. The low pass filter is disposed on a path between an output terminal of the tracker component and the power amplifier. The tracker component and the low pass filter are disposed on or in the second substrate.

The present invention is a rectangular waveguide providing amplification of an electromagnetic wave via interaction with an electron beam in a linear interaction channel where the electron beam enters the waveguide at a first curved part of the waveguide, traverses the linear interaction channel and exits the waveguide at a second curved part of the waveguide.

The present invention is a rectangular waveguide providing amplification of an electromagnetic wave via interaction with an electron beam in a linear interaction channel where the electron beam enters the waveguide at a first curved part of the waveguide, traverses the linear interaction channel and exits the waveguide at a second curved part of the waveguide.

The invention relates to a broadband high power amplifier that comprises a signal input adapted to receive an input signal, at least one amplifier stage adapted to amplify the received input signal, a signal output adapted to output the signal amplified by the at least one amplifier stage as an output signal, a monitoring unit adapted to monitor signal characteristics of the input signal and the output signal and a control unit adapted to operate the at least one amplifier stage at an optimal operating point depending on the current signal characteristics monitored by said monitoring unit.

The invention relates to a broadband high power amplifier that comprises a signal input adapted to receive an input signal, at least one amplifier stage adapted to amplify the received input signal, a signal output adapted to output the signal amplified by the at least one amplifier stage as an output signal, a monitoring unit adapted to monitor signal characteristics of the input signal and the output signal and a control unit adapted to operate the at least one amplifier stage at an optimal operating point depending on the current signal characteristics monitored by said monitoring unit.