Jaemyung Chang
Korea Advanced Institute of Science and Technology · Engineering
About the Lab
Professor Jaemyung Chang's research lab specializes in advanced integrated circuit design for wireless communication systems and next-generation solid-state batteries. The lab focuses on developing high-performance RF and mixed-signal CMOS integrated circuits, including low-noise amplifiers, mixers, and transceivers for UHF and ISM band applications, while also pioneering innovative materials and interfacial engineering for all-solid-state lithium metal batteries. Key research directions include enhancing the stability and performance of solid electrolyte interfaces, particularly in garnet-type LLZO, through dopant engineering and artificial interlayers to suppress lithium dendrite growth. The lab bridges cutting-edge semiconductor technology with sustainable energy storage solutions.
Research Overview
Research Output Trend
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Selected Papers
15Large spiral inductors encased in oxide over silicon are shown to operate beyond the UHF band when the capacitance and loss resistance are greatly reduced by selective removal of the underlying substrate. Using a 100-nH inductor whose self-resonance lies at 3 GHz, a balanced tuned amplifier with a gain of 14 dB centered at 770 MHz has been implemented in a standard digital 2- mu m CMOS IC process. The core amplifier noise figure is 6 dB, and the power dissipation is 7 mW for a 3-V supply.< <ETX
An integrated low-noise amplifier and downconversion mixer operating at 1 GHz has been fabricated for the first time in 1 /spl mu/m CMOS. The overall conversion gain is almost 20 dB, the double-sideband noise figure is 3.2 dB, the IIP3 is +8 dBm, and the circuit takes 9 mA from a 3 V supply. Circuit design methods which exploit the features of CMOS well suited to these functions are in large part responsible for this performance. The front-end is also characterized in several other ways relevant
A single-chip transceiver for frequency-hopped code division multiple access (CDMA) in the 900 MHz industrial, scientific and medical (ISM) band is implemented in 1-/spl mu/m CMOS. It combines a digital frequency synthesizer, a double quadrature upconverter, an integrated oscillator, and a power amplifier with variable output. Data modulates a carrier hopping at 20 kHz with quaternary frequency-shift keying (4-FSK). At an output power level of +3 dBm, the harmonics and spurious tones lie at -52
Abstract Securing the chemical and physical stabilities of electrode/solid‐electrolyte interfaces is crucial for the use of solid electrolytes in all‐solid‐state batteries. Directly probing these interfaces during electrochemical reactions would significantly enrich the mechanistic understanding and inspire potential solutions for their regulation. Herein, the electrochemistry of the lithium/Li 7 La 3 Zr 2 O 12 ‐electrolyte interface is elucidated by probing lithium deposition through the electr
Abstract Lithium metal batteries using solid electrolytes are considered to be the next-generation lithium batteries due to their enhanced energy density and safety. However, interfacial instabilities between Li-metal and solid electrolytes limit their implementation in practical batteries. Herein, Li-metal batteries using tailored garnet-type Li 7-x La 3-a Zr 2-b O 12 (LLZO) solid electrolytes is reported, which shows remarkable stability and energy density, meeting the lifespan requirements of
Abstract Lithium metal batteries (LMBs) with inorganic solid-state electrolytes are considered promising secondary battery systems because of their higher energy content than their Li-ion counterpart. However, the LMB performance remains unsatisfactory for commercialization, primarily owing to the inability of the inorganic solid-state electrolytes to hinder lithium dendrite propagation. Here, using an Ag-coated Li 6.4 La 3 Zr 1.7 Ta 0.3 O 12 (LLZTO) inorganic solid electrolyte in combination wi
For pt. I see ibid., vol. 33, no. 4, April 1998. A 900-MHz direct-conversion receiver to detect a frequency-hopped carrier with frequency shift keying (FSK) modulation at 160 kb/s is integrated on the same chip as the transmitter. The receiver combines a low-noise amplifier with downconversion mixers and low-pass channel-select filters in quadrature channels. A digital correlating detector makes the data decisions. The received signal is dehopped when it is down-converted. The cascade noise figu
The mechanism of Li dendrite formation for Ta-doped LLZO (LLZTO) was investigated by examining the electronic structure and the laser annealing of LLZTO was performed as a bandgap engineering method to suppress the Li dendrite formation.
A 1 GHz Low Noise Amplifier and Mixer combination has been integrated in a standard 1?m CMOS process. The circuit is matched to 50? at the input, and drives a 50? load. Overall conversion gain is 22 dB, noise figure is 3.5 dB, and the IIP3 of the combination is +12 dBm. The fully balanced circuit drains 8 mA from 3V.
This article describes a fabrication procedure of high performance flexible ferroelectric materials supported on plastic substrates and the characterization of thin films on flexible substrates. Ferroelectric thin film was deposited using radio-frequency magnetron sputtering on a Si substrate and annealed at for crystallization. The metal-insulator -metal structure was successfully transferred onto flexible substrates by the standard microfabrication and soft lithographic printing methods after
We report a solution-processed, high-performance organic thin-film transistor (OTFT), using polystyrene (PS) as interlayer with the semiconducting material P2TDPP2TFT4 as an active layer. We achieved a significant improvement employing the PS as an interlayer between the P2TDPP2TFT4 and AlO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">X</sub> gate insulator. The filed-effect mobility (μ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xl
The present investigation reports a new processing technique that can reduce the sintering temperature of Sr‐ and Mg‐doped lanthanum gallate (LSGM), a good candidate material for the electrolyte of the solid oxide fuel cell (SOFC). When LSGM was sintered at 1623 K for 5 h in N 2 or O 2 , the samples were densified over 98% relative density. In contrast, only 93% relative density was achieved after sintering in air, the conventional sintering atmosphere. As a result of better densification in N 2
Research Areas
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