Gain is suppressed. In a power amplification circuit, a first transistor has a first input terminal, a first output terminal, and a first ground terminal. A second transistor has a second input terminal, a second output terminal, and a second ground terminal. The second input terminal is connected to the first input terminal. The second output terminal is connected to the first output terminal. A first bias circuit is connected to the first input terminal. A second bias circuit is connected to the second input terminal. A first resistor is connected between the first ground terminal and the ground. A second resistor is connected between the second ground terminal and the ground. The second resistor has a resistance value greater than that of the first resistor.

A higher-speed operation of a power amplifier circuit is achieved. A power amplifier circuit includes multi-stage amplifier units, an ET terminal, and an APT terminal. The multi-stage amplifier units include a final-stage amplifier unit. The final-stage amplifier unit includes a first amplifier element and a second amplifier element that are connected in parallel with each other. The first amplifier element is connected to the ET terminal. The second amplifier element is connected to the APT terminal.

Aspects of this disclosure relate to a receiver for digital predistortion (DPD). The receiver includes an analog-to-digital converter (ADC) having a sampling rate that is lower than a signal bandwidth of an output of a circuit having an input that is predistorted by DPD. DPD can be updated based on feedback from the receiver. According to certain embodiments, the receiver can be a narrowband receiver configured to observe sub-bands of the signal bandwidth. In some other embodiments, the receiver can include a sub-Nyquist ADC.

Aspects of this disclosure relate to a receiver for digital predistortion (DPD). The receiver includes an analog-to-digital converter (ADC) having a sampling rate that is lower than a signal bandwidth of an output of a circuit having an input that is predistorted by DPD. DPD can be updated based on feedback from the receiver. According to certain embodiments, the receiver can be a narrowband receiver configured to observe sub-bands of the signal bandwidth. In some other embodiments, the receiver can include a sub-Nyquist ADC.

Apparatuses and methods for adjusting a power capability of a system is described. In an example, a system can include an antenna array and a beamformer connected to the antenna array. The beamformer can include a communication channel. The system can further include a first power converter that can be configured to convert a supply voltage to a first regulated voltage. The first power converter can apply the first regulated voltage to the beamformer. The system can further include a second power converter that can be configured to convert the supply voltage to a second regulated voltage different from the first regulated voltage. The second power converter can apply the second regulated voltage to a power amplifier in the communication channel to adjust a maximum power capability of the power amplifier.

A bias circuit includes a current generating circuit generating an internal base current based on a reference current, a bias output circuit generating a base bias current based on the internal base current and outputting the base bias current to an amplifying circuit, and a temperature compensation circuit regulating the base bias current based on a temperature voltage reflecting a change in ambient temperature.

The disclosure relates to a pre-5th-generation (5G) or 5G communication system to be provided for supporting higher data rates beyond 4th-generation (4G) communication system such as long term evolution (LTE). An operation method of a device for upconversion in a wireless communication system is provided. The method includes receiving a first local oscillator (LO) signal, generating a second LO signal, based on the first LO signal and cross-coupled latches, receiving an input signal, generating an upconverted frequency, based on the second LO signal and the input signal, generating an output signal obtained by processing a harmonic component included in the upconverted frequency, and transmitting the generated output signal.

A wideband amplifier includes a first stage and a second stage. The first stage includes a transconductance transistor driven by an input signal through an input transformer. The transconductance transistor couples to a cascode transistor forming an output node for the first stage. The second stage couples the output node from the first stage through an output transformer to drive an output transistor.

An compensation circuit for an Amplitude Modulation-Amplitude Modulation (AM-AM) of a Radio Frequency (RF) power amplifier, including: a first biasing circuit, a power amplifier, and a compensation circuit located between the first biasing circuit and the power amplifier; herein, the compensation circuit includes a diode detection circuit and a feedforward amplifier for compensating AM-AM distortion.

An compensation circuit for an Amplitude Modulation-Amplitude Modulation (AM-AM) of a Radio Frequency (RF) power amplifier, including: a first biasing circuit, a power amplifier, and a compensation circuit located between the first biasing circuit and the power amplifier; herein, the compensation circuit includes a diode detection circuit and a feedforward amplifier for compensating AM-AM distortion.