A Doherty amplifier is configured in such a way that a phase adjustment circuit adjusts either the phase of a return signal going to a first auxiliary amplification element as a result of passage of a first signal amplified by a second main amplification element through a second auxiliary amplification element as the return signal, or the phase of the return signal going to the second auxiliary amplification element as a result of reflection of the return signal by the first auxiliary amplification element, at a time of a backoff operation of the second auxiliary amplification element, in such a way that the sum of the phase of the return signal going to the first auxiliary amplification element and the phase of the return signal going to the second auxiliary amplification element is not equal to 0 degrees in the operating frequency band of the first signal.

A system, in an active reflector device, adjusts a first amplification gain of each of a plurality of radio frequency (RF) signals received at a receiver front-end from a first equipment via a first radio path of an NLOS radio path. A first phase shift is performed on each of the plurality of RF signals with the adjusted first amplification gain. A combination of the plurality of first phase-shifted RF signals is split at a transmitter front-end. A second phase shift on each of the split first plurality of first phase-shifted RF signals is performed. The plurality of RF signals as a directed beam is transmitted to a second equipment via a second radio path of the NLOS radio path.

An embodiment of a Doherty amplifier module includes a substrate, an RF signal splitter, a carrier amplifier die, and a peaking amplifier die. The RF signal splitter divides an input RF signal into first and second input RF signals, and conveys the first and second input RF signals to first and second splitter output terminals. The carrier amplifier die includes one or more first power transistors configured to amplify, along a carrier signal path, the first input RF signal to produce an amplified first RF signal. The peaking amplifier die includes one or more second power transistors configured to amplify, along a peaking signal path, the second input RF signal to produce an amplified second RF signal. The carrier and peaking amplifier die are coupled to the substrate so that the RF signal paths through the carrier and peaking amplifier die extend in substantially different (e.g., orthogonal) directions.

Embodiments describe systems, apparatuses, and methods for transmitting/receiving signal data to/from a plurality of transceiver modules. Devices in accordance with some embodiments can include a plurality of wireless transceiver modules, each wireless transceiver module to be communicatively coupled to a corresponding external transceiver mixture, one or more antennas to exchange signal data with the plurality of external transceiver modules, a radio frequency (RF) circulator, and one or more amplifiers to amplify the signal data received by the one or more antennas and signal data to be transmitted by the one or more antennas. The use of the RF circulator prevents transmitting signals that may collide with each other and cause interference with the communications.

This application is generally related to methods for improving performance in a system. One of the methods may include a step of determining whether absorbed power in a system meets a predetermined threshold. The absorbed power may be based upon first and second Walsh codes transmitted to each of first and second gain and phase modulators in the system. The first Walsh code may be orthogonal to the second Walsh code. A first set of the first and second Walsh codes may be inverted with respect to a second set of the first and second Walsh codes. The method may also include a step of modulating the absorbed power in view of the determination. The method may further include a step of transmitting feedback based upon the modulated power to the first and second gain and phase modulators.

Apparatus and methods for a low-load-modulation power amplifier are described. Low-load-modulation power amplifiers can include multiple amplifiers connected in parallel to amplify a signal that has been divided into parallel circuit branches. One of the amplifiers can operate as a main amplifier in a first amplification class and the remaining amplifiers can operate as peaking amplifiers in a second amplification class. The main amplifier can see low modulation of its load between the power amplifier's fully-on and fully backed-off states. Improvements in bandwidth and drain efficiency over conventional Doherty amplifiers are obtained.

A radio frequency (RF) transmitter includes a radiating element, a chip and a phase shifting circuit. The radiating element is arranged to receive a plurality of electrical signals to produce an RF output signal. The chip includes an amplifier circuit. The amplifier circuit is configured to amplify an RF input signal to generate a plurality of amplified signals at a plurality of output terminals, respectively. The phase shifting circuit is located outside the chip, and coupled to the output terminals and the radiating element. The phase shifting circuit is arranged to phase shift the amplified signals, and accordingly generate the electrical signals fed to the radiating element. The phase shifting circuit and the radiating element are formed on a same substrate.

A power amplifier circuit includes a power splitter, a first amplifier, a second amplifier, a third amplifier, a fourth amplifier, a first bias circuit, a first line connecting the first bias circuit and the first amplifier, and a second line connecting the first bias circuit and the third amplifier on the same semiconductor substrate, in which the first line and the second line are formed such that a voltage drop amount of the first bias voltage between the first bias circuit and the first amplifier is substantially equal to a voltage drop amount of the first bias voltage between the first bias circuit and the third amplifier.

In some embodiments, an amplifier system can include an amplifier circuit having first and second amplifiers configured to amplify respective first and second portions of an input signal. Each of the first and second amplifiers can include a cascode stage with input and output transistors arranged in a cascode configuration. The amplifier system can further include an envelope tracking bias circuit coupled to the amplifier circuit and configured to provide a bias signal to the output transistor of the cascode stage of at least one of the first and second amplifiers. The amplifier system can further include a supply circuit configured to provide a non-envelope tracking supply voltage to the output transistor of the cascode stage of the at least one of the first and second amplifiers.

Various embodiments provide systems, devices, and methods for a multi-core digital power amplifier with an unbalanced power combiner. In one example, two or more cores are combined with a transformer section that has a first coupling coefficient and another two or more cores are combined with a second transformer section that has a second coupling coefficient that is different than the first coupling coefficient. The outputs of different cores may be cross-coupled with the primary inductors of the transformers. The digital power amplifier may provide an output power that is flat over a relatively wide operating range. Other embodiments may be described and claimed.