A power amplifier (PA) system is provided for multi-mode multi-band operations. The PA system includes one or more amplifying modules, each amplifying module including one or more banks, each bank comprising one or more transistors; and a plurality of matching modules, each matching module being configured to be adjusted to provide impedances corresponding to frequency bands and conditions. A controller dynamically controls an input terminal of each bank and adjusts the matching modules to provide a signal path to meet specifications on properties associated with signals during each time interval.

An amplifier includes amplification stages connected in parallel between an input point and an output point and a feedback circuit, wherein the amplification stages each include a transistor configured to amplify a signal supplied from the input point, a harmonic processing unit configured to process harmonics present in an amplified signal output from an output node of the transistor, a connection point between the output node and the harmonic processing unit, and a transmission line connecting the connection point and the output point, wherein the feedback circuit feeds back a signal at the output point or a midway point of the transmission line of a given one of the amplification stages to a first end of a resistor connected to the connection point of the given one of the amplification stages, a second end of the resistor being connected to the connection point of another one of the amplification stages.

A first transmission line and a third transmission line are disposed at different positions in a thickness direction of a substrate. The third transmission line includes a first end portion connected to one end portion of the first transmission line, and a second end portion that is grounded. The first transmission line is electromagnetically coupled to the third transmission line. The first transmission line has a coil pattern and the third transmission line has a partially open loop pattern.

Radio-frequency devices that include metamaterial structures are provided. Inclusion of resonator sections in a structure enables the utilization of desirable line segment widths without sacrificing performance, and further enables a reduction in the amount of space or area taken up by such devices on a printed circuit board.

Systems and methods for communicating electromagnetic signals and/or power and, more particularly for example, to power combiners and similar systems and methods for communicating electromagnetic signals and/or power generated by amplifiers to loads, are described herein. In at least example embodiment, a power amplifier system includes first and second amplifier circuits and a power combiner circuit coupled to each of the first and second amplifier circuits and having a first microstrip transmission line component, a slotline formation, and an additional coupling component that is capable of being at least indirectly coupled to a load, where the first microstrip transmission line component and additional coupling component are electromagnetically coupled by way of the slotline formation.

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.

A distributed circuit includes: a first transmission line that has an input end to which an input signal is input; a second transmission line that has an output end from which an output signal is output; a plurality of unit cells that are disposed along the first and second transmission lines, the input terminals of the unit cells being connected to the first transmission line, the output terminals of the unit cells being connected to the second transmission line; two input termination resistors connected in parallel to an end of the first transmission line; and two output termination resistors connected in parallel to an end of the second transmission line. In the distributed circuit, at least one input termination resistor is a temperature-gradient resistor, and voltages at the two input termination resistors are changed symmetrically.

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.

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.

A wireless communication device includes a first low-noise amplifier (LNA). The wireless communication device also includes a first LNA load circuit coupled to an output of the LNA. The wireless communication device further includes a power splitter switchably coupled to the first LNA load circuit. The power splitter includes a negatively coupled transformer and is switchably coupled to multiple outputs.