Hong-Kyu Jang

Dr. Hong-Kyu Jang

orcid

Research Focus & Metrics

Academic Career Length

6Years (2021-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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19 January 2022 in Polymers
Verified
Journal Article
Open access
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HJHong-Kyu Jang
Hong-Kyu Jang
JKJinbong Kim
Jinbong Kim
JPJi-Sang Park
Ji-Sang Park
JMJin Bum Moon
Jin Bum Moon
JOJaecheol Oh
Jaecheol Oh
MKMin-Gyu Kang
Min-Gyu Kang
The purpose of this study is to prepare a resistive lossy material using conducting polymers for electromagnetic wave absorbers. This paper presents a conductive paste largely composed of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) with a polyurethane binder. The various secondary compounds are added in small amounts to an aqueous blended solution in order to enhance the electrical and mechanical properties of the conductive thin film. The synthesized conductive paste is characterized through electrical, chemical, and morphological analyses. The electrical conductivity of the thin film is measured using a four-point probe and surface profiler. The chemical and morphological changes are studied in various experiments using a Raman microscope, X-ray photoelectron spectroscopy, a scanning electron microscope, and an atomic force microscope. In order to verify the applicability of the synthesized conductive paste, which is composed of 70 wt% PEDOT:PSS, 30 wt% polyurethane, and secondary additives (DMAE 0.4 wt%, A-187 0.5 wt%, DMSO 7 wt%, Dynol 604 0.1 wt%, PUR 40 2.5 wt%), the Salisbury screen absorber is fabricated and evaluated in the X-band. According to the results, the absorber resonates at 9.7 GHz, the reflection loss is −38.6 dB, and the 90% absorption bandwidth is 3.4 GHz (8.2 to 11.6 GHz). Through this experiment, the applicability of the PEDOT:PSS-based conductive paste is sufficiently verified and it is found that excellent radar-absorbing performance can be realized.

14 April 2024 in Polymers
Verified
Journal Article
Open access
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YKYoung Cheol Kim
Young Cheol Kim
HJHong-Kyu Jang
Hong-Kyu Jang
GJGeunsu Joo
Geunsu Joo
Ji Hoon KimJi Hoon Kim
Ji Hoon Kim
This study aims to critically assess different micromechanical analysis models applied to carbon-fiber-reinforced plastic (CFRP) composites, employing micromechanics-based homogenization to accurately predict their effective properties. The paper begins with the simplest Voigt and Reuss models and progresses to more sophisticated micromechanics-based models, including the Mori–Tanaka and Method of Cells (MOC) models. It provides a critical review of the areas in which these micromechanics-based models are effective and analyses of their limitations. The numerical analysis results were confirmed through finite element simulations of the periodic representative volume element (RVE). Furthermore, the effective properties predicted by these micromechanics-based models were validated via experiments conducted on IM7/5320-1 composite material with a fiber volume fraction of 0.62.

17 November 2022 in IEEE Transactions on Electromagnetic Compatibility
Verified
Journal Article
Closed access
JKJinbong Kim
Jinbong Kim
HJHong-Kyu Jang
Hong-Kyu Jang
JOJaecheol Oh
Jaecheol Oh
JPJisang Park
Jisang Park
This study proposes a rational optimum design procedure for broadband radar absorbers composed of a square-loop-shaped resistive frequency selective surface (FSS) that are placed on an E-glass fabric/epoxy laminate and grounded by Cu foil covering the X-band (8–12 GHz). A rational optimum design procedure for the broadband absorbing performance was presented based on the analytical and numerical illustration. The effects of the surface resistance of the FSS and dielectric substrate on the design process and performance of the absorber are examined. The resistive FSS was fabricated using screen-printing technology with carbon-type ink as a demonstration. The demonstration samples were developed considering the sectional profile of the circuit lines composing the printed FSS. It revealed that the experimental reflection loss encompassing the frequency range over the entire X-band was repeatable and similar to the simulation result.

30 September 2021 in Polymers
Verified
Journal Article
Open access
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YKYoung Cheol Kim
Young Cheol Kim
YHYoon Soon Ho
Yoon Soon Ho
GJGeunsu Joo
Geunsu Joo
HJHong-Kyu Jang
Hong-Kyu Jang
JKJi-Hoon Kim
Ji-Hoon Kim
Ji Hoon KimJi Hoon Kim
Ji Hoon Kim
This study describes the numerical simulation results of aluminum/carbon-fiber-reinforced plastic (CFRP) hybrid joint parts using the explicit finite-element solver LS-DYNA, with a focus on capturing the failure behavior of composite laminates as well as the adhesive capacity of the aluminum–composite interface. In this study, two types of adhesive modeling techniques were investigated: a tiebreak contact condition and a cohesive zone model. Adhesive modeling techniques have been adopted as a widely commercialized model of structural adhesives to simulate adhesive failure based on fracture mechanics. CFRP was studied with numerical simulations utilizing LS-DYNA MAT54 to analyze the crash capability of aluminum/CFRP. To evaluate the simulation model, the results were compared with the force–displacement curve from numerical analysis and experimental results. A parametric study was conducted to evaluate the effect of different fracture toughness values used by designers to predict crash capability and adhesive failure of aluminum/CFRP parts.

4 July 2024 in International Journal of Impact Engineering
Verified
Journal Article
Closed access
GJGeunsu Joo
Geunsu Joo
YKYoung Cheol Kim
Young Cheol Kim
HJHong-Kyu Jang
Hong-Kyu Jang
JKJinbong Kim
Jinbong Kim
MJMungyu Jeong
Mungyu Jeong

28 February 2026 in Aerospace
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Journal Article
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JOJaecheol Oh
Jaecheol Oh
MKMaengchang Kang
Maengchang Kang
JJJunpyo Jo
Junpyo Jo
SBSeungwoo Bang
Seungwoo Bang
HCHyeon-Seok Choe
Hyeon-Seok Choe
HJHong-Kyu Jang
Hong-Kyu Jang
This paper presents a broadband compact omnidirectional UHF antenna–radome package for airborne applications, where reliable communication, low observability, and electromagnetic compatibility are critical. Omnidirectional radiation is essential for maintaining consistent radio communication links regardless of aircraft attitude during flight. Conventional blade antennas achieve such coverage but suffer from increased aerodynamic drag, higher radar cross-section (RCS), and limited conformal integration capability. To address these limitations, a low-profile hybrid structure combining a patch radiator with a broadband monocone is proposed. An integrated metallic ground wall reduces sensitivity to installation surroundings, suppresses structural interference, and enhances RF (Radio Frequency) compatibility. The antenna achieves an electrical size of 0.555λ × 0.555λ × 0.072λ at 338 MHz. A lightweight sandwich-structured glass fiber-reinforced plastic (GFRP) radome is fabricated to ensure mechanical robustness and environmental protection while maintaining negligible RF loss. Measurements confirm a −10 dB bandwidth of 32.7%, stable omnidirectional radiation, and gain exceeding −0.2 dBi throughout the operating band with peak realized gain of 2.6 dBi within the investigated frequency range. The radome causes negligible gain degradation, with insertion loss below 0.4 dB. The proposed package provides a practical solution for airborne platforms requiring compact, broadband, and installation-resilient antenna systems.