Postech Foundation

Samsung Electronics Co., Ltd.

Postech Academy-industry Foundation

Pohang University of Science and Technology Foundation

Bumman Kim

Young Yun Woo

Youngoo Yang

Jae Hyok Yi

Jihoon Kim

Juho Son

Byungjoon Park

Kyunghoon Moon

Daechul Jeong

Seung Woo Kim

Il-Du Kim

Seokwon Lee

Jangheon Kim

Jeonghyeon Cha

Joung Hyun Yim

Dong-Geun Lee

Kyoung-Tae Kim

Jung-Hwan Son

Junghwan Moon

Ildu Kim

Jaehyok Yi

Seonghan Ryu

Junyoul Lim

The method and system for converging a 5th-generation (5G) communication system for supporting higher data rates beyond a 4th-generation (4G) system with a technology for internet of things (IoT) are provided. The method includes intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. The system includes a power amplification device capable of minimizing the effect of envelope impedance. The power amplification device may be incorporated in a terminal and a base station.

Power amplification device, terminal having the same, and base station having the same

An apparatus of a power amplifier is provided. The apparatus includes an input boosting circuit configured to match a second harmonic input signal using a harmonic control circuit of an input stage to maximize an efficiency and an output power, a die cell configured to receive and amplify an output signal of the input boosting circuit, and an output boosting circuit configured to receive an output signal of the die cell and to match a second harmonic output signal of the output signal of the die cell using a harmonic control circuit of an output stage to maximize the efficiency and the output power.

Apparatus and method for matching harmonics

An apparatus and an operating method of an asymmetric Doherty power amplifier. A Doherty power amplifier apparatus includes a power divider configured to provide a power signal to a carrier amplifier and a peaking amplifier. The apparatus also includes the carrier amplifier configured to amplify a power of the signal input from the power divider. The apparatus further includes the peaking amplifier configured to have a maximum output power magnitude different from the carrier amplifier and amplify the power of the signal input from the power divider. The apparatus still further includes at least two offset transmission lines disposed at ends of the carrier amplifier and the peaking amplifier and configured to regulate a load impedance. The apparatus also includes an output combiner configured to combine and output outputs of the carrier amplifier and the peaking amplifier of different sizes.

Apparatus and method for improving performance in Doherty amplifier

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

A power amplifying apparatus includes a Doherty amplifier having a carrier amplifier and a peaking amplifier connected in parallel, each having an input/output matching circuit and an asymmetric power driver for driving the carrier amplifier and the peaking amplifier using an asymmetric power driver.

Power amplifying apparatus using asymmetric power drive

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 multi-layer dielectric resonant device has a dielectric resonator and a microstrip line to be coupled to the dielectric resonator. The dielectric resonator includes a first dielectric layer, a second dielectric layer, a third dielectric layer, a metallic substrate and a metallic plate. The second dielectric layer is placed on the first dielectric layer and has a dielectric constant higher than that of the first dielectric layer. The third dielectric layer is placed on the second dielectric layer and has a dielectric constant lower than that of the second dielectric layer. The metallic substrate is placed in the center portion of the second dielectric constant layer to reduce the conductor loss of the dielectric resonator. The metallic plate constitutes the outer wall of the dielectric resonator.

Dielectric resonator having a multilayer structure

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 microwave Doherty amplifier employs a way-extension in which N ways (N&#x2267;2, N is a natural number) are established, and envelope tracking for high efficiency and linearity of the power amplifier of a mobile communications base station or of a handset with improved reliability. The Doherty amplifier includes N ways, where N&#x2267;2 and N is a natural number; a carrier amplifier which is placed on one of the N ways; peak amplifiers which are placed on respective ways of the (N&#x2212;1) ways excluding the way on which the carrier amplifier is placed; a power distribution unit which distributes power to each of the N ways; and a quarter wave impedance transformer at which the N ways meet.

Doherty amplifier

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.

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Pohang, South Korea

Bumman Kim