A5102809202- Magnetic properties of thin films
- Antenna Design and Analysis
- Microwave Engineering and Waveguides
- Advanced Antenna and Metasurface Technologies
- Magnetic Properties and Applications
- Ferroelectric and Piezoelectric Materials
- Metallic Glasses and Amorphous Alloys
- Magnetic Properties of Alloys
- Fluid Dynamics and Thin Films
- ZnO doping and properties
- Theoretical and Computational Physics
- Magnetic and transport properties of perovskites and related materials
- Microwave Dielectric Ceramics Synthesis
- Copper Interconnects and Reliability
- Semiconductor materials and devices
- Physics of Superconductivity and Magnetism
- nanoparticles nucleation surface interactions
- Acoustic Wave Resonator Technologies
- Magneto-Optical Properties and Applications
- Full-Duplex Wireless Communications
- Heusler alloys: electronic and magnetic properties
- Quantum and electron transport phenomena
- Electromagnetic Compatibility and Measurements
- Nanomaterials and Printing Technologies
- Characterization and Applications of Magnetic Nanoparticles
Kwangwoon University
2011-2024
Providence College
2022-2023
Nokia (United States)
2022-2023
University of Colorado Boulder
2013-2018
Chung-Ang University
2013
Hanyang University
2009-2013
Korea Food Research Institute
2012
Korea Aerospace University
2005
Korea Institute of Science and Technology
2004
Tohoku University
1999-2001
The demand for data across all communication networks continues to grow exponentially. This in turn requires an increase both capacity and density of backhaul point-to-point (PTP) point-to-multipoint (PTMP) links. D-band frequency range (110 170GHz) offers ample spectrum acceptable propagation characteristics next generation, high-data-rate systems [1], [2]. A transceiver (TRX) coupled with a 2D phased-array module can overcome the free-space path loss flat panel added capabilities such as...
A wideband patch antenna loaded with a planar metamaterial unit cell is proposed. The composed of an interdigital capacitor and complementary split-ring resonator (CSRR) slot. dispersion analysis the reveals that increase in series capacitance can decrease half-wavelength resonance frequency, thus reducing electrical size proposed antenna. In addition, circulating current distributions around CSRR slot increased finger length bring about TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML"...
A monostatic dual-polarized simultaneous transmit and receive (STAR) antenna system with high isolation is introduced. beamforming network (BFN) producing 0°, ±90°, ±180°, ±270° phase progression used to feed TX RX ports of four elements arranged in a sequential rotation array (SRA). Due the geometrical symmetry SRA, coupling from canceled at port BFN; therefore, infinite theoretically obtained. Full-wave simulations are verify theory study effects element spacing BFN imbalances. An...
An implantable zeroth-order resonance (ZOR) antenna is proposed. By using chip inductors, an epsilon negative ZOR was generated, while achieving extremely compact size. The has the overall dimensions of 0.021λ0×0.017λ0×0.002λ0 at Medical Implantable Communication Service (MICS) band (402–405 MHz) and 10 dB return loss bandwidth 2.2% ranging from 400 to 409 MHz. Furthermore, performance proposed insensitive electrical properties human body by virtue phenomenon.
First-principles calculations of the magnetic anisotropy energies Pd/Co metallic multilayers have been performed to investigate effect strain on interface anisotropy. Also, clarify contribution anisotropy, an unsupported Co monolayer and bulk calculated. These two systems different interfaces compared multilayer in sense that can be considered as vacuum/Co Co/Co multilayers, respectively. A is predicted exhibit a perpendicular accordance with experiment. Bulk shows but energy quite small...
A first-principles calculation of the magnetic anisotropy energies X/Co (X=Pt, Cu, Ag and Au) metallic multilayers has been performed to investigate effect strain on anisotropy. It is successfully predicted that Pt/Co Au/Co exhibit perpendicular anisotropies in accordance with experiments. The strength hybridization electronic states at interface determines relative position Fermi energy local density (LDOS) ‖m‖=2 character Co d electrons minority spin. If LDOS large energy, a system shows...
A reverse-phase ultra-high-performance liquid chromatography (u-HPLC) method was developed for the rapid quantification of 22 ginsenosides in ginseng products. The proposed analysis is based on a heating-block without further treatment. u-HPLC separation performed reversed C18 column (100 × 2 mm id, particle size µm) followed by ultraviolet detection at 203 nm. Aqueous 50% methanol used as extraction solvent. optimum amount solvent and time were 20 mL min (extracted twice with 10 mL),...
A dual-band on-body antenna for a wireless body area network repeater system is proposed. The designed has the maximum radiation directed toward inside of human in medical implantable communication service (MICS) band order to collect vital information from and outside industrial, scientific, (ISM) transmit that monitoring system. In addition, return loss property insensitive effects by utilizing epsilon negative zeroth-order resonance property.
The magnetic current in an annular slot is used to enhance the impedance bandwidth of a monopole and preserve consistent radiation patterns from K-band through V-band. equivalent circuit models monopole, slot, their combination are derived aid RF system analysis with this antenna, herein referred as combined slot-monopole antenna. proposed antenna designed using full-wave simulations theory experimentally validated. measured VSWR below 2 17.9 50 GHz. A far-field characterized monopole-like...
The anisotropy energies of (111) and (001) oriented Ag/Fe Au/Fe multilayers are obtained by a first-principle calculation to investigate the orientational dependence magnetic anisotropy. All systems show perpendicular in good agreement with experiments. In case multilayers, anisotorpy energy multilayer is larger than that multilayer. contrast Ag/Fe, Au/Fe(111) exhibits stronger system. all systems, large minority-spin LDOS | m =2 character Fe near Fermi could be origin
In this paper, a Multi-Input Multi-Output (MIMO) antenna is proposed. The isolation characteristic of proposed MIMO between two radiating elements improved by using Split Ring Resonator (SRR) array structure. fabricated satisfied the 10 dB return loss requirement and was higher than 15 in Mobile-WiMAX frequency band. measured peak gains were 2.3 dBi 2.4 dBi.
The influence of Ti seed layers on the structure self-organized Ag nanodots, obtained with a seed-layer-assisted thermal agglomeration method, has been investigated. samples were grown MgO(001) single crystal substrates by RF magnetron sputter deposition. deposited at room temperature and post-annealed 350 °C for 4 h while maintaining chamber vacuum conditions. results atomic force microscopy (AFM) observations indicated that insertion layer (0.6–5.0 nm) between MgO substrate promotes...
A wide-boom, microstrip-fed planar bidirectional log-periodic (LP) antenna is proposed and improvements in its impedance match, radiation, thermal performances are demonstrated. The boom width of each arm increased by moving virtual apexes into the other while preserving small flare angle self-complementarity. This modification widens ground plane for microstrip feed line results enhanced match gain. In addition, electrothermal multi physics analysis demonstrates that wide-boom mitigates hot...
An eight-element circular array of miniaturized combined transverse electromagnetic horn and loop elements for joint frequency time operation is presented. The use such ultrawideband compact directional element leads to stable wideband radiation patterns with moderate gain omnidirectional phase mode 0 operation. Moreover, a enabled by simply exciting specific element(s) in the also demonstrated. Obtained beams can be steered desired direction horizontal plane an appropriate element. Low...
Thermomigration (TM)-induced failures occurred in the current-confined-path (CCP) current perpendicular-to-the plane (CPP) giant magnetoresistance spin valve (GMR SV) read sensors with Cu nanopillar metal paths (∼5 nm diameter) operating at a high density (J&gt;2×107 A/cm2) have been numerically studied to explore magnetic and electrical stability. The interdiffusion (migration) from nanopillars into adjacent layers (e.g., CoFe) due thermally induced mass transport was found be main...
A semiquantitative characterization of the interfacial adhesion phase change materials is developed, which consists determining critical temperature (TCA) via measuring probability failure with using patterned films. By comparison TCA values, Ge-doped SbTe (Ge-ST) shown to have weaker than Ge2Sb2Te5 (GST), results from its limited ability in relaxation crystallization-induced stress. Nitrogen or oxygen doping Ge-ST produces significant increase TCA, close that GST. This improvement due...