According to one embodiment, an amplifier circuit includes N (N>=3) transistors, two first branches and N2 second branches. The N (N>=3) transistors are connected in parallel. The two first branches each include the transistor and a first transmission line which is connected to an output terminal of the transistor. The N2 second branches each include the transistor and a second transmission line which is connected to the output terminal of the transistor. For each of the first branches, a sum between an electrical length of a parasitic component of the transistor and the electrical length of the first transmission line are odd multiples of approximately 90 degrees. For each of the second branches, the sum between the electrical length of the parasitic component of the transistor and the electrical length of the second transmission line are multiples of approximately 180 degrees.

A power amplifying radiator is disclosed that includes an electric field receiver or radiofrequency (RF) energy coupling and impedance matching element, a capacitive coupler, a cavity combiner including a coaxial-cavity section providing electromagnetic communication with the capacitive coupler, and a phased-array antenna/one or more phased-array antennas. The RF energy coupling and impedance matching element is in electromagnetic communication with the one or more phased-array antennas via the cavity combiner. The cavity combiner includes a center conductor configured and disposed to project from the coaxial-cavity section such that the cavity combiner defines a co-axial cross-sectional configuration. The power amplifying radiator may be included within a high power microwave system.

A system having a set of power amplifiers each having a primary inductive structure configured to provide an output signal. A secondary inductive structure is configured to inductively couple to each of the primary inductive structures. A transmission line is provided with a signal trace and a ground trace. The signal trace of the transmission line is connected to a first end of the secondary inductive structure. A return path from a second end of the secondary inductive structure is coupled via a resonant network to the ground trace of the transmission line, in which the return path is spaced away from the secondary inductive structure to minimize inductive coupling to the primary structures.

Power amplifiers such as multi-path power amplifiers, systems employing such amplifiers, and methods of implementing amplifiers and amplifier systems are disclosed herein. In one example embodiment, a multi-path power amplifier includes a first semiconductor die with an integrated first transistor having a first source-to-drain pitch, and a second semiconductor die with an integrated second transistor having a second source-to-drain pitch, where the second source-to-drain pitch is smaller than the first source-to-drain pitch by at least 30 percent. In another example embodiment, a Doherty amplifier system includes a first semiconductor die with a first physical die area to total gate periphery ratio, and a second semiconductor die with a second physical die area to total gate periphery ratio, where the second physical die area to total gate periphery ratio is smaller than the first physical die area to total gate periphery ratio by at least 30 percent.

A power amplifier cell comprising a first power amplifier, a second power amplifier and a balun. The balun comprises a first inductor and a second inductor that define a first transformer; and a third inductor and a fourth inductor that define a second transformer. The following: (i) a parasitic capacitance of the first power amplifier; (ii) a leakage inductance of the first transformer; and (iii) a capacitive coupling between the first inductor and the second inductor, contribute to a first impedance matching circuit for the first power amplifier. Also, the following (iv) a parasitic capacitance of the second power amplifier; (v) a leakage inductance of the second transformer; and (vi) a capacitive coupling between the third inductor and the fourth inductor, contribute to a second impedance matching circuit for the second power amplifier.

Aspects of temperature dependent stabilization and peaking control in amplifiers are described. An example amplifier includes a variable gain amplifier, a power amplifier, a variable compensation element coupled to the variable gain amplifier, and a controller that directs operation of the variable compensation element to adjust one or more operating characteristics of the amplifier. In one aspect, the variable compensation element comprises a variable impedance, and the controller varies the impedance across inputs of the variable gain amplifier based on temperature to stabilize the amplifier. In another aspect, the variable compensation element comprises a negative capacitance, and the controller varies a coupling of the negative capacitance across inputs of the variable gain amplifier based on temperature to linearize gain of the amplifier. The variable compensation element can include both a variable impedance and negative capacitance, and stability, peaking control, and linearity of the amplifier can be controlled.

A power management apparatus operable with multiple configurations is disclosed. In embodiments disclosed herein, the power management apparatus can be configured to concurrently generate multiple modulated voltages based on a configuration including a single power management integrated circuit (PMIC) or a configuration including a PMIC and a distributed PMIC. Regardless of the configuration, the power management apparatus employs a single switcher circuit, wherein multiple reference voltage circuits are configured to share a multi-level charge pump (MCP). As a result, it is possible to reduce footprint of the power management apparatus while improving isolation between the multiple modulated voltages.

A sound system includes a sound source having an analogue audio signal output and a sound volume control; signal amplifier apparatus (10) comprising an analogue signal input (12) configured to be coupled to the analogue audio signal output of the sound source, an analogue signal output (18) and an amplifier module (62) coupled between the signal input and the signal output. The amplifier module (62) has a fixed amplification gain within a range of 10 to 12 decibels. Control of the audio signal is effected solely by the sound volume control of the sound source. The amplifier module (64) also provides a fixed gain bass boost of 6 decibels. The system provides linear amplification and allows a user to reduce the volume of the sound source, which significantly reduces signal distortion. Volume control is at the sound source and not at the amplifier module, which optimises amplification quality and reduces the power requirement of the amplifier apparatus (10).

A multi-gain LNA with inductive source degeneration is presented. The inductive source degeneration is provided via a tunable degeneration network that includes an inductor in parallel with one or more switchable shunting networks. Each shunting network includes a shunting capacitor that can selectively be coupled in parallel to the inductor. A capacitance of the shunting capacitor is calculated so that a combined impedance of the inductor and the shunting capacitor at a narrowband frequency of operation is effectively an inductance. The inductance is calculated according to a desired gain of the LNA. According to one aspect, the switchable shunting network includes a resistor in series connection with the shunting capacitor to provide broadband frequency response stability of the tunable degeneration network. According to another aspect, the LNA includes a plurality of selectable branches to further control gain of the LNA.

An impedance control unit is disclosed. Also disclosed are a balun unit, an electronic device, and a Doherty amplifier, each comprising the impedance control unit.

The impedance control unit comprises a pair of re-entrant type coupled lines, and further comprises an electrical short between the intermediate plane and the ground plane arranged locally inside the pair of coupled lines.