A method for transforming the impedance of a radio-frequency transmission line of a printed circuit from a first impedance value to a second impedance value, the radio-frequency transmission line being adapted to transport a radio-frequency signal at a frequency value comprised in a frequency range defined between a minimum frequency value and a maximum frequency value, wherein the following steps are envisaged:—dividing the radio-frequency transmission line into a plurality of circuit sections each one of the circuit sections including a first and a second impedance connected in parallel with each other by two circuit branches placed at a maximum distance (d.sub.max) from each other, wherein the circuit sections have respective third impedance values that gradually increase, respectively decrease, from the first impedance value to the second impedance value;—determining the maximum distance between the circuit branches in such a way as to avoid any undesired frequency values within the frequency range;—setting a fourth impedance value of one of the two impedances;—calculating a fifth impedance value of the other one of the two impedances, such that the impedance value of the circuit section is the third respective impedance value.

An on-chip transformer circuit is disclosed. The on-chip transformer circuit comprises a primary winding circuit comprising at least one turn of a primary conductive winding arranged as a first N-sided polygon in a first dielectric layer of a substrate; and a secondary winding circuit comprising at least one turn of a secondary conductive winding arranged as a second N-sided polygon in a second, different, dielectric layer of the substrate. In some embodiments, the primary winding circuit and the secondary winding circuit are arranged to overlap one another at predetermined locations along the primary conductive winding and the secondary conductive winding, wherein the predetermined locations comprise a number of locations less than all locations along the primary conductive winding and the secondary conductive winding.

A multiple-path amplifier (e.g., a Doherty amplifier) includes a first transistor (e.g., a main amplifier FET), a second transistor (e.g., a peaking amplifier FET), a combining node, and a shunt-inductance circuit. The first and second amplifiers and the combining node structure are integrally-formed with a semiconductor die, and the shunt-inductance circuit is integrated with the die. Outputs of the first and second transistors are electrically coupled to the combining node structure. The shunt-inductance circuit is electrically coupled between the combining node structure and a ground reference node. The shunt-inductance circuit includes a shunt inductance (e.g., including wirebond(s) and/or spiral inductor(s)) that is integrated with the semiconductor die. The multiple-path amplifier also may include an integrated phase shifter/impedance inverter coupled between the outputs of the first and second transistors, and which is configured to impart a 90-degree phase delay between intrinsic drains of the first and second transistors.

A front-end module of a wireless device can replace a passive duplexer with an active duplexer that uses metamaterial matching circuits. The active duplexer can be formed from a power amplifier circuit and a low noise amplifier circuit that each include a metamaterial matching circuit. The combination of a power amplifier circuit and a low noise amplifier circuit that each utilize metamaterials to form the associated matching circuit can provide the functionality of a duplexer without including the additional circuitry of a stand-alone or passive duplexer. Thus, in certain cases, the front-end module can provide duplexer functionality without including a separate duplexer. Advantageously, in certain cases, the size of the front-end module can be reduced by eliminating the passive duplexer. Further, the loss introduced into the signal path by the passive duplexer is eliminated improving the performance of the communication system that includes the active duplexer.

A power amplifier module can be formed that includes metamaterial matching circuits. This power amplifier module can be included as part of a front-end module of a wireless device. The front-end module can replace a passive duplexer with an active duplexer that uses the power amplifier module in combination with a low noise amplifier circuit that can include a metamaterial matching circuit. The combination of PA and LNA circuits that utilize metamaterials can provide the functionality of a duplexer without including a stand-alone or passive duplexer. Thus, in certain cases, the front-end module can provide duplexer functionality without including a separate duplexer. Advantageously, in certain cases, the size of the front-end module can be reduced by eliminating the passive duplexer. Further, the loss introduced into the signal path by the passive duplexer is eliminated improving the performance of the communication system that includes the active duplexer.

A plurality of transmission lines (3b,3c) are connected to a transistor (1) and have different characteristic impedances. A plurality of open stubs (4a,4b) are connected to the plurality of transmission lines (3b,3c) respectively. A length of each open stub (4a,4b) is shorter than a length of each transmission line (3b,3c).

An RF power package includes a substrate having a metallized part and an insulating part, an RF power transistor die embedded in or attached to the substrate, the RF power transistor die having a die input terminal, a die output terminal, an input impedance and an output impedance, a package input terminal formed in the metallized part or attached to the insulating part of the substrate, a package output terminal formed in the metallized part or attached to the insulating part of the substrate, and a first plurality of planar tuning lines formed in the metallized part of the substrate and electrically connecting the die output terminal to the package output terminal. The first plurality of planar tuning lines is shaped so as to transform the output impedance at the die output terminal to a higher target level at the package output terminal.

A monolithic microwave integrate circuit (MMIC) presents as a power amplifier including a 9:1 overlay transformer and artificial low impedance transmission lines. The 9:1 overlay transformer effects the output impedance thereof. The artificial low impedance transmission lines behave as inductors without occupying an amount of space equivalent to that of an inductor having similar properties as the artificial low impedance transmission line.

A control circuit (16) is configured to detect the impedance P1 of a load (3) and control each of the reactance value L1 of a first variable reactance element (12), the reactance value L2 of a second variable reactance element (14), and the phase shift amount φ of a phase shifter (15) on the basis of the detected impedance P1. Consequently, impedance matching can be achieved even with the phase shifter (15) that performs discrete phase shift control.

The present invention discloses an impedance matching circuit and method. The circuit is applied to a power supply circuit of an envelope tracking radio frequency power amplifier. An envelope tracking power supply is connected with a radio frequency power amplifier through a first matching circuit. The envelope tracking radio frequency power amplifier obtains the optimal efficiency by performing matching according to an optimal efficiency load impedance of the envelope tracking power supply and a conjugate impedance of an optimal efficiency load impedance of the radio frequency power amplifier.