A digital microwave radio system includes a splitter that splits a common baseband input into two baseband outputs, first and second transmitters, each transmitter electrically connected to a baseband output of the splitter via a mixer, a common local oscillator electrically connected to the mixer of the first transmitter and the mixer of the second transmitter via an adjustable phase shifter, respectively, and a combiner. The common local oscillator is configured to up-convert each baseband output into a radio-frequency signal using a corresponding mixer. The combiner combines the two radio-frequency signals into a 0-degree phase-shift output and a 180-degree phase-shift output, respectively. A phase error control loop adjusts the phase shifter to minimize the 180-degree phase-shift radio-frequency output. A combiner gain control loop adjusts the output power level of the two transmitters in accordance with an actual power detector reading at the 0-degree phase-shift radio-frequency output.

Doherty power amplifiers and devices are described with a low voltage driver stage in a carrier-path and a high voltage driver stage in a peaking-path. In an embodiment a Doherty power amplifier has a carrier-path driver stage transistor configured to operate using a first bias voltage at the driver stage output, and a final stage transistor configured to operate using a second bias voltage at the final stage output. A peaking-path driver stage transistor is configured to operate using a third bias voltage at the driver stage output, and a final stage transistor electrically coupled to the driver stage output of the peaking-path driver stage transistor is configured to operate using a fourth bias voltage at the final stage output, wherein the third bias voltage is at least twice as large as the first bias voltage.

A radio frequency module includes: a module board that includes a first principal surface and a second principal surface on opposite sides of the module board; a power amplifier configured to amplify a transmission signal; a first circuit component; and a power amplifier (PA) control circuit configured to control the power amplifier. The power amplifier and the PA control circuit are stacked on the first principal surface, and the first circuit component is disposed on the second principal surface.

Power amplification system with variable supply voltage. A power amplification system can include a power amplifier and a boost converter configured to provide a supply voltage to the power amplifier. The power amplification system can include a control system configured to provide a boost converter control signal to the boost converter to adjust the supply voltage based on a parameter associated with the power amplifier.

Methods and devices to improve nonlinearity performance of low noise amplifiers (LNAs) are disclosed. The described methods and devices reduce the capacitive loading of the LNA amplifying devices on the bypass path of the LNAs when operating in the bypass mode. This is performed by decoupling the active devices from ground to put the amplifying devices in a floating state, thus minimizing the impact of the gate-source capacitances of the amplifying devices on the overall linear performance of the LNA operating in the bypass mode.

A complementary balanced low-noise amplifier is disclosed. In one aspect, the low-noise amplifier (LNA) may be a single-ended cascoded complementary common-source LNA that is capable of operating in low-power conditions. In particular, the LNA may include a first path with a common-source amplifier formed from an N-type material and a second path with a common-source amplifier formed from a P-type material that collectively form a complementary common-source amplifier. By providing two paths in the complementary amplifier, headroom may be preserved for output transistors. Additionally, higher-order intercept points (e.g., IP2 or IP3) characteristics have better performance profiles resulting in better overall performance and improved user experience.

A technology related to a power amplifier used in a wireless communication circuit is disclosed. A radio frequency (RF) power amplifier includes a plurality of unit differential amplifiers of which inputs are connected to a common input terminal and outputs are connected to a common adder, and having a gain of a weight of a corresponding bit of a binary gain control word. Each of the differential amplifiers may be configured as a complementary metal-oxide semiconductor (CMOS) differential cascode amplifier. In addition, the RF power amplifier may include a structure in which a plurality of attenuators of the same structure are cascade-connected so that an attenuation rate may be linearly and digitally controlled and an output of each attenuator is connected to an output adder through differential buffers of which turn-on and turn-off are controlled by a controller.

To provide a monitoring system capable of monitoring, without stopping operations for a long period of time, a change of the characteristics of an apparatus to be subjected to characteristic measurement, to which high frequency signals are inputted. [Solution] A signal to be monitored and a reference signal are inputted to an input unit 11 , and the input unit inputs one of the inputted signals to an apparatus 15 to be subjected to characteristic measurement. On the basis of an output signal of the apparatus 15 and the reference signal in the cases where the reference signal is inputted to the apparatus, an input/output characteristic calculation unit 12 calculates the input/output characteristics of the apparatus 15 . On the basis of calculation results obtained from the input/output characteristic calculation unit 12, a correction result generating unit 13 generates a correction result signal that indicates the results obtained by correcting an output signal of the apparatus 15 in the cases where the signal to be monitored is inputted to the apparatus. On the basis of the correction result signal generated by the correction result generating unit 13 , a failure determining unit 14 determines whether the apparatus has a failure.

A radio frequency filter includes communication bandpass filters disposed corresponding respectively to a plurality of communication bands, a switch, and a matching circuit. The switch includes a common terminal and a plurality of optionally selectable terminals, the plurality of optionally selectable terminals being individually connected to the plurality of bandpass filters in a one-to-one relation. The matching circuit is connected to the common terminal and is a common matching circuit to the plurality of communication bandpass filters. The plurality of communication bandpass filters are set such that filter characteristics of a serial circuit in combination of one of the plurality of communication bandpass filters, the one being selected by the switch, and the common matching circuit are improved in comparison with filter characteristics of the selected communication bandpass filter with respect to the communication band corresponding to the selected communication bandpass filter.

A transmitter is provided. The transmitter includes a bus system including at least two bus lines. Further, the transmitter includes an envelope tracking circuit coupled to the at least two bus lines, and a plurality of power amplifiers. At least a first one of the plurality of power amplifiers, while in active state, is configured to selectively couple its input to the one of the at least two bus lines which is supplied with a supply voltage or a bias signal by the envelope tracking circuit that is based on an envelope of a first baseband signal related to a first radio frequency signal received by the first one of the plurality of power amplifiers for amplification.