An amplifier circuit with in-band gain degradation compensation is shown. The amplifier circuit has an input-stage amplifier, at least one intermediate-stage amplifier, and an output-stage amplifier cascaded between an input port and an output port of the amplifier circuit. A compensation capacitor is coupled between the output port of the amplifier circuit and an output port of the input-stage amplifier. A high-order damping circuit is coupled to an output port of the intermediate-stage amplifier.

An example object of the present invention is to provide a power amplifier with better conversion efficiency. The power amplifier including a power amplifier circuit that includes: a first switching element; a second switching element; a first capacitor; and a second capacitor. The first switching element is controlled by a first PWM signal generated from an input signal. The second switching element is controlled by a second PWM signal in a reverse phase to the first PWM signal. The first capacitor is a capacitor connected in parallel to the first switching element. The second capacitor is a capacitor connected in parallel to the second switching element.

A digital envelop tracker for a power amplifier. The digital envelop tracker includes a supply filter for filtering a supply voltage to a power amplifier, a level selection circuitry configured to determine a level of supply voltage based on an instantaneous power of an input data stream, schedule a series of switching events based on the determined level of supply voltage, and generate a level select signal based on the scheduled series of switching events, and a switch for connecting one of supply voltages to the supply filter based on the level select signal. The level selection circuitry schedules a primary switching event of the switch based on the determined level of supply voltage and secondary switching events of the switch delayed with respect to the primary switching event based on the determined level of supply voltage to generate a filter response of the supply filter with smaller peaking.

A modified-material-based high-precision combined antenna for satellite navigation and communications includes a high-frequency satellite navigation antenna metal radiating surface, a low-frequency satellite navigation antenna metal radiating surface, a WIFI/Bluetooth antenna metal radiating surface, a PCB, a shielding metal cavity and an injection molded modified-material-based substrate. The low-frequency satellite navigation antenna metal radiating surface is located between the high-frequency satellite navigation antenna metal radiating surface and the PCB. The WIFI/Bluetooth antenna metal radiating surface is located on a side of the low-frequency satellite navigation antenna metal radiating surface. The injection molded modified-material-based substrate is made of polyphenyl ether doped with a modified material, and the modified material has a relative permittivity of 2.65 and a density of 1.06 g/cm.sup.3. The injection molded modified-material-based substrate includes a first injection molded modified-material-based substrate and a second injection molded modified-material-based substrate.

Systems and methods are provided for amplifying multiple input signals to generate multiple output signals. An example system includes a first channel, a second channel, and a third channel. The first channel is configured to receive one or more first input signals, process information associated with the one or more first input signals and a first ramp signal, and generate one or more first output signals. The second channel is configured to receive one or more second input signals, process information associated with the one or more second input signals and a second ramp signal, and generate one or more second output signals. The first ramp signal corresponds to a first phase. The second ramp signal corresponds to a second phase. The first phase and the second phase are different.

A high frequency amplifier circuit includes an input terminal and an output terminal, transmission power amplifiers (11L, 11H) that amplify a high frequency signal in first and second frequency bands, each of which is a part of a communication band, at equal to or higher than a prescribed amplification factor, respectively, switches (21, 31) that exclusively switch connection between the input terminal, the transmission power amplifier (11L), and the output terminal, and connection between the input terminal, the transmission power amplifier (11H), and the output terminal, and a transmission filter that is connected between the output terminal and the switch (31) and has a communication band as a pass band, the first frequency band including a frequency band other than the second frequency band, the second frequency band including a frequency band other than the first frequency band.

A power supply for supplying a power to a heating mechanism used for heating a measurement target that emits a measurement signal includes an input device configured to output an input signal that reflects a control signal in a differentiable periodic waveform having a frequency of 1 kHz or less. The power supply includes a switching amplifier configured to amplify the input signal from the input device and output the amplified signal.

An output matching circuit includes: a converter electrically connected to an output end of a power amplifier element to convert an impedance of the output end to an impedance higher than the impedance of the output end by magnetic coupling; and a first filter circuit electrically connected between the output end of the power amplifier element and the converter to make a short circuit in a frequency band different from a predetermined transmission frequency band.

Desired characteristics can be achieved. A radio-frequency circuit includes an inductor and a switch. The inductor has a first end and a second end. The switch has a first input-output terminal, a second input-output terminal, a first switching terminal coupled to the first end of the inductor, and a second switching terminal coupled to the second end of the inductor. The switch can switch between a first state and a second state. In the first state, the first input-output terminal is coupled to the first switching terminal, and the second input-output terminal is coupled to the second switching terminal. In the second state, the first input-output terminal is coupled to the second switching terminal, and the second input-output terminal is coupled to the first switching terminal.

Systems and methods are disclosed for on-chip harmonic filtering for radio frequency (RF) communications. For disclosed embodiments, a filter circuit is coupled between a first internal node and a connection pad for an integrated circuit. The filter circuit includes a first inductance, a variable capacitance, and a second inductance. The capacitance amount for the variable capacitance is controlled to tune filtering for the filter circuit to a harmonic of a frequency for a transmit output signal. A power amplifier outputs the transmit output signal to the connection pad without passing through the filter circuit. The filter circuit filters the harmonic of the frequency for the transmit output signal, shunting harmonic current to ground. For one embodiment, the filtered harmonic is a third harmonic of the transmit frequency. For one embodiment, the transmit output signal has an output power greater than or equal to 15 dBm.