Changkun Park

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A load-shared CMOS power amplifier (PA) for 1.8-GHz polar transmitter applications has been implemented in standard 0.18-mum CMOS technology and fully characterized to demonstrate its efficiency boosting technique in low power mode. With the aid of cascode amplifiers, the load-shared configuration achieves efficiency improvement at low supply voltage in a(More)
A 1.9-GHz CMOS differential power amplifier for a polar transmitter is implemented with a 0.18-mum RF CMOS process. All of the matching components, including the input and output transformers, are fully integrated. The concepts of injection locking and variable load are applied to increase the efficiency and dynamic range of the amplifier. An asymmetric(More)
A quasi-four-pair structure of an RF CMOS power amplifier (PA) is proposed. The structure is applied to a 1.8-GHz class-E CMOS PA for a global system for mobile communications with a 0.18-mum RF CMOS process. This allows a simple design, as well as a high output power. The transistor size issues of the cascode PA are also studied. An integrated passive(More)
A tournament-shaped magnetically coupled power-combiner architecture for a fully integrated RF CMOS power amplifier is proposed. Various 1 : 1 transmission line transformers are used to design the power combiner. To demonstrate the new architecture, a 1.81-GHz CMOS power amplifier using the tournament-shaped power combiner was implemented with a 0.18-mum RF(More)
A class-E power amplifier is proposed in this study. It uses both nMOS and pMOS as switching devices to reduce the voltage stress of each transistor. A voltage-combining scheme with nMOS and pMOS is proposed, and a transformer is designed using this scheme. The power amplifier is implemented in a 0.18-mum RF CMOS process. Measurements show a maximum output(More)
A 1.8-GHz CMOS power amplifier for a polar transmitter is implemented with a 0.18- RF CMOS process. The matching components, including the input and output transformers, were integrated. A dual-primary transformer is proposed in order to increase the efficiency in the low power region of the amplifier. The loss induced by the matching network for the(More)
A fully integrated CMOS RF power amplifier for a 1.8 GHz band EDGE polar transmitter is presented. It is implemented with 0.18-mum CMOS process. The output power is 33.4 ~ 33.5 dBm and the power added efficiency is 39 ~ 41 percent when the frequency varies from 1.71 to 1.91 GHz. The dynamic range is increased by 12 dB with the use of the proposed switchable(More)
A 900-MHz linear power amplifier has been fabricated for ultra-high-frequency (UHF) radio frequency identification (RFID) reader applications using a 0.25-mum CMOS technology. An on-chip transmission-line transformer is used for output matching network. Input and inter-stage matching components, and RF chokes are fully integrated in the designed amplifier(More)
Meteorite studies suggest that each solar system object has a unique oxygen isotopic composition. Chondrites, the most primitive of meteorites, have been believed to be derived from asteroids, but oxygen isotopic compositions of asteroids themselves have not been established. We measured, using secondary ion mass spectrometry, oxygen isotopic compositions(More)
A 1.8 GHz power amplifier for a polar transmitter application is implemented with 0.18 mum RF CMOS technology, and a differential line inductor is proposed for the differential circuit. The differential line inductor is used as a low power matching network in the stage-convertible power amplifier in order to increase the efficiency of a low output power(More)