Postech Foundation

Samsung Electronics Co., Ltd.

Postech Academy-industry Foundation

Pohang University of Science and Technology Foundation

Young Yun Woo

Bumman Kim

Youngoo Yang

Jae Hyok Yi

Seung Woo Kim

Jangheon Kim

Junghwan Moon

Jaehyok Yi

A linear amplification with nonlinear components (LINC) power transmitter is provided. The LINC power transmitter includes a digital signal processing unit which controls the LINC power transmitter; a frequency modulation unit which modulates or converts a digital signal output from the digital signal processing unit into a radio-frequency (RF) signal; a signal amplification unit which amplifies the RF signal output from the frequency modulation unit using a gain amplifier and a power amplification module; and a direct current/direct current (DC/DC) conversion unit which controls bias of the power amplification module. Here, the DC/DC conversion unit controls a base bias and/or a collect bias of the power amplification module, and the power amplification module operates in saturation.

LINC power transmitter

A Doherty power amplifying apparatus includes a harmonic-controlled Doherty amplifier; and an input matching unit and an output matching unit for input matching and output matching the harmonic-controlled Doherty amplifier, respectively. The harmonic-controlled Doherty amplifier includes a carrier amplifier; a peaking amplifier arranged in parallel to the carrier amplifier; and a harmonic control circuit, arranged in front of the output matching unit, for controlling a harmonic component of an output of the Doherty amplifier to enable the Doherty amplifier to perform a switching or saturation operation.

Doherty amplifying apparatus using a harmonic control circuit

Provided is a digital feedback linearizing apparatus and method to linearize a power amplifier (PA), which is intended to improve the linearity of a mobile communication base station PA, and more particularly, a digital feedback linearizing apparatus and method to linearize a PA using a digital signal process (DSP) and a feedback technology, in which a predistorted signal required for linearization is generated by adding an input signal input through a predetermined path to an inverse distortion component corresponding to a distortion component of an PA and in which a linearly amplified output signal is obtained by passing the predistorted signal through the PA.

Digital feedback linearizing apparatus to linearize power amplifier and method used by the apparatus

A linearized amplification apparatus includes a means for dividing an input signal into a main channel signal and a subsidiary channel signal, a PAR (Peak-to-Average power Ratio) adjustment block for reducing a PAR of the main channel signal to generate a sub-main signal having a reduced PAR compared to the PAR of the main channel signal, an error extraction block for extracting an error signal from the subsidiary channel signal and amplifying the error signal, the amplified error signal corresponding to distortion components in the sub-main signal, and a means for coupling the sub-main signal with the amplified error signal to generate an output signal having an increased PAR compared to the PAR of the sub-main signal.

Linearization apparatus capable of adjusting peak-to-average power ratio

A feedforward amplifier, and a method of improving the performance thereof, are provided. More particularly, a feedforward amplifier using imperfect cancellation of a main signal and a method of improving the performance thereof, in which, by including a predetermined amount of a main signal in an error signal that is input to an error signal cancellation loop of the feedforward amplifier, more error components of a final output signal are removed, such that the linearity and efficiency of the final output signal improve.

Feedforward amplifier and method of improving the performance thereof

A predistortion linearizer for predistorting a radio frequency(RF) signal includes a power divider, an even order harmonics generator and a predistortion component producer. The power divider divides the RF signal into a first and a second RF signals. The even order harmonics generator, responsive to the second RF signal, generates one or more even order harmonics of the fundamental frequencies. And, the predistortion component producer produces one or more odd order harmonics from the fundamental frequencies and the even order harmonics to provide a predistorted RF signal including the fundamental frequencies and the odd order harmonics. The power divider divides the RF signal into first and second RF signals and delays the first RF signal.

Predistortion linearizer using even order intermodulation components

Quarter wave transformers are connected to final outputs of a carrier amplifier and a peaking amplifier, which are coupled in parallel to each other, so as to induce a Doherty operation of a microwave Doherty amplifier. Load matching circuits for obtaining a microwave output matching are connected to output terminals of the carrier amplifier and the peaking amplifier. A phase tuning component is positioned behind the load matching circuit. Accordingly, a matching state can be maintained without being changed at a high power level but can be adjusted depending on phase variations at a low power level to attain efficiency enhancements and optimum linearity.

Growing community of inventors

Pohang, South Korea

Young Yun Woo