A Doherty amplifier has a first amplifier path that includes a first amplifier, a second amplifier path that includes a second amplifier, a power divider, and a short-circuited stub. The power divider receives an RF signal and divides the RF signal into first and second input signals. The power divider includes first and second power divider outputs that produce the first and second input signals, respectively. The short-circuited stub is coupled between the first power divider output and the first amplifier or between the second power divider output and the second amplifier. The first and second amplifier paths are characterized by first and second frequency-dependent insertion phases, respectively. A slope of the first or second frequency-dependent insertion phase is altered by the short-circuited stub. The power divider produces the first and second input signals with a quadrature phase shift.

A power amplifier includes a first amplifier configured to amplify a first high-frequency signal, a second amplifier configured to amplify a second high-frequency signal delayed with respect to the first high-frequency signal by at least 90 degrees, a hybrid coupler including a first transmission line and a second transmission line, a first power-supply circuit for the first amplifier, a second power-supply circuit for the second amplifier, and an output matching network. The hybrid coupler is connected to an output end of the first amplifier at a first end of the first transmission line. The first transmission line is connected to the first power-supply circuit and the output matching network at a second end. The second transmission line is connected to an output end of the second amplifier at a first end. The second transmission line is connected to the second power-supply circuit at a second end.

A balanced amplifier system having input and output quadrature couplers or equivalents thereof and two amplifiers there between. An RF signal is presented to a first input of an input quadrature coupler such that an amplified RF signal is output at a first output of the output quadrature coupler. A RF control signal is presented to a second input of the quadrature coupler such that an amplified control signal is outputted at the other output of the output quadrature coupler. The system is configured to reflect the amplified signal back into the second port of the output quadrature coupler in order to vary an impedance seen by the amplifiers of the balanced amplifier.

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.

A multistage linear power amplifier receiving an input signal. The multistage linear power amplifier comprises a plurality of Class-AB amplifiers connected in a cascade configuration. The plurality of Class-AB amplifiers amplifies the input signal to generate an amplified input signal. At least one of the plurality of Class-AB amplifiers is biased such that the multistage linear power amplifier emulates a Class-C amplifier.

An amplifier arrangement (200) for amplifying input signals and a method for operating the amplifier arrangement are disclosed. The amplifier arrangement (200) comprises a main amplifier circuit (210) having an input and an output; a first (221) and second (222) auxiliary amplifier circuits each having an input and an output, wherein each of the first (221) and second (222) auxiliary amplifier circuits being selectively operable to operate in combination with the main amplifier circuit (210). The amplifier arrangement (200) further comprises a single hybrid coupler circuit (230) having a first port (221) being coupled to the output of the main amplifier circuit (210), a second port (232) being coupled to the output of the first auxiliary amplifier circuit (221), a third port (233) being coupled to the output of the second auxiliary amplifier circuit (222) and a fourth port (234) being coupled to the load (240) of the amplifier (200).

The present invention provides an amplifier arrangement for amplifying a broadband signal, the amplifier arrangement comprising a signal splitter configured to receive the broadband signal and output a first split signal and a second split signal, and a balanced amplifier that is coupled to the signal splitter and is configured to amplify the first split signal and the second split signal and is configured to output a single amplified broadband signal based on the amplified first split signal and the amplified second split signal. The present invention further provides a respective method.

A directional coupler includes a main line through which a first signal in a first frequency band and a second signal in a second frequency band pass from a first port to a second port, a sub-line electromagnetically coupled to the main line and having a third port and a fourth port, the third port outputting a first coupled signal corresponding to the first signal and a second coupled signal corresponding to the second signal, a first termination circuit connected to the fourth port and used in outputting the first coupled signal, a second termination circuit connected to the fourth port and used in outputting the second coupled signal, and a first filter circuit disposed between the fourth port and the first termination circuit, wherein the first filter circuit has frequency characteristics allowing the first coupled signal to pass therethrough and attenuating the second coupled signal.

Disclosed is a reconfigurable power amplifier having a 2.sup.N?1 number of input-side reconfigurable quadrature couplers connected in a tree structure, wherein a 2.sup.(N?1) number of the input-side reconfigurable quadrature couplers have coupler output terminals, and a root of the tree structure is one of the input-side reconfigurable quadrature couplers having a main input terminal. Also included is a 2.sup.N?1 number of output-side reconfigurable quadrature couplers connected in a tree structure, wherein a 2.sup.(N?1) number of the output-side reconfigurable quadrature couplers have coupler input terminals, and a root of the tree structure is one of the output-side reconfigurable quadrature couplers having a main output terminal. Further included is a 2.sup.N number of constituent amplifiers divided into amplifier pairs having amplifier input terminals connected to corresponding ones of the coupler output terminals and having amplifier output terminals coupled to corresponding ones of the coupler input terminals.

The present invention relates to a four-way Doherty amplifier. The invention further relates to a mobile telecommunications base station.

The invention proposes a new Doherty combiner topology that allows peak efficiencies to be reached at deeper back-off levels than conventional Doherty combiners.