A radio-frequency module includes a first base, which has at least a part formed of a first semiconductor material and which includes a low-noise amplifier circuit, a second base, which has at least a part formed of a second semiconductor material having a thermal conductivity lower than that of the first semiconductor material and which includes a power amplifier circuit, and a module substrate, which has a principal surface on which the first base and the second base are disposed. The first base is joined to the principal surface with electrodes interposed in between. The second base is disposed between the module substrate and the first base in cross-sectional view, and is joined to the principal surface with an electrode interposed in between. At least a part of the first base overlaps at least a part of the second base in plan view.

A communication system for SAR (Specific Absorption Rate) reduction includes an RF (Radio Frequency), an antenna element, a coupler, and a controller. The RF module provides RF power. The antenna element is excited by the RF module. The coupler is coupled between the RF module and the antenna element. The controller receives antenna information from the coupler. The controller adjusts the level of RF power according to the antenna information.

A radio-frequency assembly is described which can be used in communication satellites, for example. The radio-frequency assembly contains a signal source in the form of a semiconductor amplifier output, an impedance matching filter, and a radio-frequency waveguide. The impedance matching filter is connected to the semiconductor amplifier output on the input side and to the radio-frequency waveguide on the output side. The impedance matching filter has a different impedance value on the input side from that on the output side and is matched to the semiconductor amplifier output on the input side and matched to the radio-frequency waveguide on the output side. Consequently, a separate matching circuit between semiconductor amplifier output and radio-frequency waveguide is no longer necessary.

Broadband feedforward power amplifiers are disclosed herein. In certain embodiments, a broadband feedforward power amplifier includes a power amplifier electrically connected between a radio frequency (RF) input and an RF output, and a feedforward compensation circuit including a first amplifier electrically connected in parallel with the power amplifier, a load impedance, and a second amplifier electrically connected between the radio frequency input and the load impedance. The feedforward compensation circuit generates a compensation signal based on sensing an output of the first amplifier and an output of the second amplifier, and provides the compensation signal to the radio frequency output to thereby compensate the power amplifier for non-linearity.

The invention relates to a directional coupler comprising a non-straight main conductor line for receiving a high power signal and at least one coupling element. The main conductor line is arranged to run in a plane P.sub.0. The at least one coupling element is arranged sectionally parallel to the main conductor line. Further, the invention relates to a method for measuring RF voltage and/or RF power using a directional coupler. The method comprises the steps of combining the measured signals of the directional coupler and the measured voltage and current values of the VI sensor unit. In case, one of the measured signals has a low or zero level the sensitivity of the measuring of RF voltage and/or RF power is increased.

A digital radio frequency (RF) transmitter including processing circuitry configured to generate first through third pattern signals based on a pattern of an inphase (I)-quadrature (Q) binary data pair and a pattern of an inverted I-Q binary data pair, the first through third pattern signals having a same pattern and different phases, and a switched-capacitor digital-to-analog converter (SC-DAC) configured to remove an n-th harmonic component of an RF analog signal by amplifying the first through third pattern signals to have a certain magnitude ratio and synthesizing the amplified first through third pattern signals into the RF analog signal, where “n” is an integer of at least 3, may be provided.

Radio frequency (RF) systems with tunable filters are provided herein. In certain embodiments, an RF system includes a first RF processing circuit configured to process a first frequency band of a first communication standard and a second frequency band of a second communication standard. The first frequency band and the second frequency band are close in frequency and/or partially overlapping in frequency. The first RF processing circuit includes a tunable filter for changing the bandwidth of the first RF processing circuit to enhance the robustness of the first RF processing circuit to blocker or jammer signals of a third frequency band.

In some embodiments, stability in power amplifiers can be achieved under high in-band voltage standing wave ratio condition, with an amplifier circuit that includes an amplifier having a first stage and a second stage, with each stage including an input and an output, such that the output of the first stage is coupled to the input of the second stage. The amplifier circuit further includes a stabilizing circuit implemented on the input side of the second stage and configured to provide stability in operation of the amplifier under a high in-band voltage standing wave ratio condition.

This disclosure provides techniques for impedance matching. A radio frequency (RF) device includes a power detector to determine a transmitter leakage and a post-processing unit to determine a receiver leakage, and determines if isolation is acceptable based on the leakages. The RF device may include a device for measuring antenna impedance. Otherwise, the RF device may select multiple tuner settings (e.g., capacitor values) for test signals to be transmitted and received at a target frequency, determine multiple sets of leakage values, determine multiple reflection coefficients based on the multiple sets of leakage values, and determine an estimated antenna impedance at the target frequency based on the reflection coefficients. The RF device then determines impedance tuner settings based on the measured or estimated antenna impedance. Alternatively, the RF device determines impedance tuner settings using an inverse machine-learning model based on a determined matching impedance.

A matching circuit includes first and second ports, an autotransformer, and first and second capacitors. The autotransformer includes a first terminal coupled to a first port, a second terminal coupled to a second port, and a common terminal coupled to a reference potential, and includes a series parasitic inductor and a parallel parasitic inductor. The first capacitor is coupled in shunt to the second terminal, and defines a low pass filter together with the series parasitic inductor. The second capacitor is coupled in series between the first port and the first terminal, and defines a high pass filter together with the parallel parasitic inductor.