A multi-frequency tunable low-noise amplifier and a multi-frequency tuning implementation method therefor. The amplifier comprises: a system controller (13) and a micro-electro-mechanical system (MEMS) matching tuner (12) connected to the system controller (13). The system controller (13) is configured to respond to a first operation executed by a user via a user interface (15) when in a first mode, to acquire a first matching value produced on the basis of the first operation, and to output the first matching value to the MEMS matching tuner (12). The MEMS matching tuner (12) is configured to be controlled by the system controller (13) and to support the amplifier working on different frequency bands in tuning processing, thus allowing the matching value of the MEMS matching tuner (12) itself to match a current working frequency band.

An amplifier system including a push-pull power amplifier having an input to receive a radio frequency (RF) input signal and an output, the push-pull power amplifier being configured to amplify the RF input signal and provide at the output an RF output signal that is an amplified version of the RF input signal, a switchable shunt capacitance switchably connected between a load-line connected to the output of the push-pull power amplifier and a reference potential, and a switch configured to selectively connect the switchable shunt capacitance to the reference potential and disconnect the switchable shunt capacitance from the reference potential to vary an impedance of load-line.

An adaptive power amplifier and a radio frequency transmitter thereof are described. The radio frequency transmitter is a transmitter to transmit a transmission signal for a wireless communication system. The radio frequency transmitter includes at least one direct-current (DC) to direct-current (DC) converter coupled to an external power supply device for operation, a digital-to-analog converter configured to convert a digital signal into an analog signal, a filter configured to filter a harmonic component of the analog signal to generate an input signal, a RF up-converter configured to up-convert the input signal according to a desired channel frequency for generating a modulated signal, and a power amplifying circuit coupled to the DC-to-DC converter and the external power supply device, for selectively receiving one of different supply voltages for operation, and amplifying the modulated signal to generate a RF output signal.

A method and an apparatus for improving signal quality through noise detection in an electronic device are provided. The electronic device may include a power amplifier configured to amplify and output a transmitted signal, a noise detector configured to detect noise in a receiving band by the power amplifier and to output a power level of the detected noise, and a processor configured to acquire the power level of the noise through the noise detector, acquire control information to change the output power of the power amplifier based on the power level of the noise, and control the output power of the power amplifier based on the control information.

A broadcast receiving device for a motor vehicle includes at least one antenna having a given antenna impedance, an antenna amplifier having a given amplifier impedance and a matching circuit which is configured to adapt the antenna impedance to the amplifier impedance. The broadcast receiving device is characterized in that the matching circuit is arranged outside of the amplifier core of the antenna amplifier.

A power amplification circuit that includes: a capacitor element in which a first metal layer, a first insulating layer, a second metal layer, a second insulating layer and a third metal layer are sequentially stacked, the capacitor element including a first capacitor in which the first metal layer serves as one electrode thereof and the second metal layer serves as another electrode thereof, and a second capacitor in which the second metal layer serves as one electrode thereof and the third metal layer serves as another electrode thereof; and a transistor that amplifies a radio-frequency signal. The radio-frequency signal is supplied to the one electrode of the first capacitor. The other electrode of the first capacitor and the one electrode of the second capacitor are connected to a base of the transistor, and the other electrode of the second capacitor is connected to the emitter of the transistor.

An electrical device (e.g., an integrated circuit) includes an amplifier, a configurable common mode gain trim circuit, and a memory. The configurable common mode gain trim circuit is coupled to the amplifier. The memory is configured to include trim data that is usable during an initialization process for the electrical device to configure the impedance matching circuit.

Aspects of this disclosure relate to an amplification circuit that includes a stacked amplifier and a bias circuit. The stacked amplifier includes at least a first transistor and a second transistor in series with each other. The stacked amplifier is operable in at least a first mode and a second mode. The bias circuit is configured to bias the second transistor to a linear region of operation in the first mode and to bias the second transistor as a switch in the second mode. In certain embodiments, the amplification circuit can be a power amplifier stage configured to receive a supply voltage that has a different voltage level in the first mode than in the second mode.

Radio frequency (RF) amplification devices are disclosed that include Doherty amplification circuits and methods of operating the same. In one embodiment, a Doherty amplification circuit includes a main carrier RF amplifier, a peaking RF amplifier, and a periodic quadrature coupler. To provide Doherty amplification, the peaking RF amplifier is configured to be deactivated while an RF signal is below a threshold level and is configured to be activated while the RF signal is above the threshold level. The periodic quadrature coupler is configured to combine a first RF split signal from the main carrier RF amplifier and a second RF split signal from the peaking RF amplifier into the RF signal, such that the RF signal is output from an output port while the peaking RF amplifier is activated. The periodic quadrature coupler allows the Doherty amplification circuit to provide broadband amplification in various RF communication bands.

A high frequency amplifier includes a high frequency amplifier transistor integrated in a first die of a first semiconductor technology and a matching circuit. The high frequency amplifier transistor has an input terminal, an output terminal and a reference terminal. The reference terminal is coupled to a reference potential. The matching circuit includes at least a first inductive bondwire, a second inductive bondwire and a capacitive element arranged in series with said inductive bondwires. The capacitive element is integrated in a second die of a second semiconductor technology different from the first semiconductor technology. The second semiconductor technology includes an isolating substrate for conductively isolating the capacitive element from a support attached at a first side to the second die. The capacitive element includes a first plate electrically coupled to a first bondpad of the second die and a second plate electrically coupled to a second bondpad of the second die.