Beamforming channels of a satellite are calibrated using a low power, spread spectrum calibration signal. The power of the calibration signal is below the noise level of a user signal in an active channel, allowing channels to be calibrated while active. When calibrating the transmit side circuitry, a two-stage calibration can be used, first calibrating the output hybrid matrix, then calibrating the whole of the transmit side. To improve performance, the dwell time spend calibrating a channel can be based on the power of the user signal in the channel. A transmit probe can be used to inject a calibration signal into the receive antennae and a receive probe can be used to extract the calibration signal from the transmit antennae. To reduce frequency of calibrations, the calibrations can be based on path-to-path differences. These techniques are also applied to multiport amplifiers (MPAs).

A Doherty amplifier including: a first transistor for main amplifier having a source-to-drain parasitic capacitance and operating in class AB; a transmission line whose input end is connected to an output end of the first transistor and whose output end is connected to a composite point; a second transistor for auxiliary amplifier having a source-to-drain parasitic capacitance and operating in class C; a series capacitor whose input end is connected to an output end of the second transistor and whose output end is connected to the composite point, and to reduce the capacitance value of impedance seen from the composite point toward the output end of the second transistor at the time of a backoff operation; and an output matching circuit connected between the composite point and a point of connection to an output load, to match the impedance of the composite point to the impedance of the output load.

Systems and apparatuses are disclosed that include an RF generator configured to generate RF signals having a wavelength. Amplifiers are configured to receive and amplify the RF signals from the RF generator and are separated from each other by a separation distance in a range between about 0.2 times the wavelength and about 10.0 times the wavelength. A power management system is configured to control one or more of the amplifiers based on information received that is associated with the RF signals.

In a Doherty amplifier including a carrier amplifier (6) and a peaking amplifier (8) connected in parallel with each other, a compensation circuit (9) for causing an impedance seen from an output end (9a) of the compensation circuit (9) toward the peaking amplifier (8) to be open within a used frequency range and compensating for frequency dependence of an impedance seen from an output of a combiner (10) toward the combiner (10) in a state in which the peaking amplifier (8) is not operating is arranged between the peaking amplifier (8) and the combiner (10). This achieves a wider bandwidth without making the circuit larger in size and more complicated.

An amplification unit contains two or more sets containing a plurality of amplification circuits, and amplifies power of an RF (Radio Frequency) signal. A combining unit contains two or more combiners corresponding to the two or more sets, combines RF signals output by the amplification circuits, and outputs a resultant RF signal. The amplification unit has one chassis storing each amplification circuit. The amplification unit and the combining unit have two or more connectors which are arranged transversely. The amplification unit and the combining unit are attachable/detachable.

An amplification unit contains two or more sets containing a plurality of amplification circuits, and amplifies power of an RF (Radio Frequency) signal. A combining unit contains two or more combiners corresponding to the two or more sets, combines RF signals output by the amplification circuits, and outputs a resultant RF signal. The amplification unit has one chassis storing each amplification circuit. The amplification unit and the combining unit have two or more connectors which are arranged transversely. The amplification unit and the combining unit are attachable/detachable.

An RF amplifier is described including an input, an output, a parallel arrangement of a first branch and at least one further branch, each branch comprising a bipolar transistor in a degenerative emitter configuration having a base coupled to the input, a collector coupled to a common collector node, and an emitter degeneration impedance arranged between the emitter and a common rail. The common collector node is coupled to the output, the base of the first branch bipolar transistor is biased at a first bias voltage and the base of the at least one further branch bipolar transistor is biased at a bias voltage offset from the first bias voltage. In operation of the RF amplifier a IM3 distortion current output by the first branch bipolar transistor is in antiphase to a IM3 distortion current output by the at least one further branch bipolar transistor.

The embodiments described herein provide wideband highly asymmetrical power efficient amplifier device that include a compact input power distribution network with input termination circuit. The input termination circuit is configured to provide control of the power distribution at the amplifier input. In one embodiment, the input termination circuit is configured to generate and reflect a frequency dependent portion of an input signal back toward the amplifier device inputs. This input reflection controls the input power distribution and shape of time domain input signal in a way that can affect amplifier device efficiency and linearity.

A power amplifier includes a main amplifier, an auxiliary amplifier, and a control circuit. The main amplifier is configured to amplify input power, and the auxiliary amplifier is configured to amplify the input power when the input power exceeds a certain level. The control circuit, which is provided between a source of the main amplifier and a ground, is configured to control a source potential of the main amplifier so as to increase the source potential when the input power reaches at least a certain value.

A power amplification device capable of detaching an element relating to the power amplification of an RF signal from an element relating to the combining of RF signals. The amplifying unit 1 is provided with a plurality of groups of amplifier circuits 2 that amplifies the power of a RF signal and the plurality of groups of amplifier circuits each includes a predetermined number of the amplifier circuits 2. A combining unit 5 includes a first combiner 7 and a second combiner 8. The first combiner 7 is provided in association with the group of the amplifier circuits 2, combines RF signals output from the amplifier circuits 2 belonging to the corresponding group, and outputs the RF signal after combining. The second combiner 8 combines the RF signals output from each first combiner 7 and outputs the RF signal after combining. Each first combiner 7 is a combiner usable for an RF signal in a specific frequency band. The amplifying unit 1 is attachable to and detachable from the combining unit 5.