• ETRI Journal
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• 제31권3호
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• pp.247-253
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• 2009

We propose a Ku-band driver and high-power amplifier monolithic microwave integrated circuits (MMICs) employing a compensating gate bias circuit using a commercial 0.5 ${\mu}m$ GaAs pHEMT technology. The integrated gate bias circuit provides compensation for the threshold voltage and temperature variations as well as independence of the supply voltage variations. A fabricated two-stage Ku-band driver amplifier MMIC exhibits a typical output power of 30.5 dBm and power-added efficiency (PAE) of 37% over a 13.5 GHz to 15.0 GHz frequency band, while a fabricated three-stage Ku-band high-power amplifier MMIC exhibits a maximum saturated output power of 39.25 dBm (8.4 W) and PAE of 22.7% at 14.5 GHz.

• Transactions on Electrical and Electronic Materials
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• 제14권5호
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• pp.235-241
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• 2013

A low power CMOS control circuit is applied in an integrated DC-DC buck converter. The integrated converter is composed of a feedback control circuit and power block with 0.35 ${\mu}m$ CMOS process. A current-sensing circuit is integrated with the sense-FET method in the control circuit. In the current-sensing circuit, a current-mirror is used for a voltage follower in order to reduce power consumption with a smaller chip-size. The N-channel MOS acts as a switching device in the current-sensing circuit where the sensing FET is in parallel with the power MOSFET. The amplifier and comparator are designed to obtain a high gain and a fast transient time. The converter offers well-controlled output and accurately sensed inductor current. Simulation work shows that the current-sensing circuit is operated with an accuracy of higher than 90% and the transient time of the error amplifier is controlled within $75{\mu}sec$. The sensing current is in the range of a few hundred ${\mu}A$ at a frequency of 0.6~2 MHz and an input voltage of 3~5 V. The output voltage is obtained as expected with the ripple ratio within 1%.

• ETRI Journal
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• 제32권1호
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• pp.151-153
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• 2010

A highly efficient linear and compactly integrated series-type Doherty power amplifier (PA) has been developed for wideband code-division multiple access handset applications. To overcome the size limit of a typical Doherty amplifier, all circuit elements, such as matching circuits and impedance transformers, are fully integrated into a single monolithic microwave integrated circuit (MMIC). The implemented PA shows a very low idle current of 25 mA and an excellent power-added efficiency of 25.1% at an output power of 19 dBm by using an extended Doherty concept. Accordingly, its average current consumption was reduced by 51% and 41% in urban and suburban environments, respectively, when compared with a class-AB PA. By adding a simple predistorter to the PA, the PA showed an adjacent channel leakage ratio better than -42 dBc over the whole output power range.

• ETRI Journal
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• 제35권3호
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• pp.546-549
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• 2013

A Ka-band 6-W high power microwave monolithic integrated circuit amplifier for use in a very small aperture terminal system requiring high linearity is designed and fabricated using commercial 0.15-${\mu}m$ GaAs pHEMT technology. This three-stage amplifier, with a chip size of 22.1 $mm^2$ can achieve a saturated output power of 6 W with a 21% power-added efficiency and 15-dB small signal gain over a frequency range of 28.5 GHz to 30.5 GHz. To obtain high linearity, the amplifier employs a class-A bias and demonstrates an output third-order intercept point of greater than 43.5 dBm over the above-mentioned frequency range.

• ETRI Journal
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• 제36권3호
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• pp.498-501
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• 2014

A C-band 50 W high-power microwave monolithic integrated circuit amplifier for use in a phased-array radar system was designed and fabricated using commercial $0.25{\mu}m$ AlGaN/GaN technology. This two-stage amplifier can achieve a saturated output power of 50 W with higher than 35% power-added efficiency and 22 dB small-signal gain over a frequency range of 5.5 GHz to 6.2 GHz. With a compact $14.82mm^2$ chip area, an output power density of $3.2W/mm^2$ is demonstrated.

• ETRI Journal
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• 제29권6호
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• pp.785-793
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• 2007

In this paper, we present an integrated rail-to-rail fully differential operational transconductance amplifier (OTA) working at low-supply voltages (1.5 V) with reduced power consumption and showing high DC gain. An embedded adaptive biasing circuit makes it possible to obtain low stand-by power dissipation (lower than 0.17 mW in the rail-to-rail version), while the high DC gain (over 78 dB) is ensured by positive feedback. The circuit, fabricated in a standard CMOS integrated technology (AMS 0.35 ${\mu}m$), presents a 37 V/${\mu}s$ slew-rate for a capacitive load of 15 pF. Experimental results and high values of two quality factors, or figures of merit, show the validity of the proposed OTA, when compared with other OTA configurations.

• 한국전자파학회논문지
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• 제27권12호
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• pp.1069-1074
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• 2016

본 논문에서는 TSMC 65 nm CMOS 공정를 이용하여 V-대역 이단 전력증폭기를 설계 및 제작하였다. 수동소자를 사용한 간단한 구조의 정합회로를 구성하였고, 입력과 출력 정합회로를 모두 집적하였다. Pre-distortion 기법을 통해 전력 이득을 보상해 줌으로써 전력증폭기의 선형성을 향상시켰다. 제작된 전력증폭기는 58.8 GHz의 동작 주파수와 1 V의 동작 전압에서 10.4 dB의 전력 이득, 9.7 dBm의 출력 전력 및 20.8 %의 효율 특성을 나타내었다.

• JSTS:Journal of Semiconductor Technology and Science
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• 제12권4호
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• pp.426-432
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• 2012

A fully-integrated low power K-band radar transceiver in 130 nm CMOS process is presented. It consists of a low-noise amplifier (LNA), a down-conversion mixer, a power amplifier (PA), and a frequency synthesizer with injection locked buffer for driving mixer and PA. The receiver front-end provides a conversion gain of 19 dB. The LNA achieves a power gain of 15 dB and noise figure of 5.4 dB, and the PA has an output power of 9 dBm. The phase noise of VCO is -90 dBc/Hz at 1-MHz offset. The total dc power dissipation of the transceiver is 142 mW and the size of the chip is only $1.2{\times}1.4mm^2$.

• 한국전기전자재료학회논문지
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• 제17권2호
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• pp.162-170
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• 2004

A 900MHz CMOS RF power amplifier with digitally controllable output power has been proposed and designed with 0.6${\mu}{\textrm}{m}$ standard CMOS technology. The designed power amplifier was composed of digitally controllable switch mode pre-amplifiers with an integrated 4nH spiral inductor load and class-C output stage. Especially, to compensate the 1ow Q of integrated spiral inductor, cascode amplifier with a Q-enhancement circuit is used. It has been shown that the proposed power control technique allows the output power to change from almost 3dBm to 13.5dBm. And it has a maximum PAE(Power Added Efficiency) of almost 55％ at 900MHz operating frequency and 3V power supply voltage.

• ETRI Journal
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• 제38권5호
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• pp.972-980
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• 2016

An ultra-wideband microwave monolithic integrated circuit high-power amplifier with excellent input and output return losses for phased array jammer applications was designed and fabricated using commercial $0.25-{\mu}m$ AlGaN/GaN technology. To improve the wideband performance, resistive matching and a shunt feedback circuit are employed. The input and output return losses were improved through a balanced design using Lange-couplers. This three-stage amplifier can achieve an average saturated output power of 15 W, and power added efficiency of 10% to 28%, in a continuous wave operation over a frequency range of 6 GHz to 18 GHz. The input and output return losses were demonstrated to be lower than -15 dB over a wide frequency range.