Jungsuek Oh

Prof. Jungsuek Oh

Department of Electrical and Computer Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Korea
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Academic Career Length

20Years (2007-Present)

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

Representative Publications

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16 June 2021 in IEEE Transactions on Antennas and Propagation
Verified
Journal Article
Closed access
JSJungwoo Seo
Jungwoo Seo
IYInseop Yoon
Inseop Yoon
JJJaebaek Jung
Jaebaek Jung
JRJeongki Ryoo
Jeongki Ryoo
JPJuhyoung Park
Juhyoung Park
JOJungsuek Oh
Jungsuek Oh
This article proposes a miniaturized antenna in package (AiP) for 5G millimeter-wave smartphone that incorporates broadside and endfire arrays and supports a dual band covering 28 and 39 GHz. This article demonstrates that the proposed AiP is $5.8\,\,\text {mm} \times 19\,\,\text {mm} \times 1.122$ mm. It is believed that this is the smallest 5G AiP that can support a 10 dBi antenna gain, a 10 dB return-loss bandwidth of 3 GHz, and more than 10 dB isolation for both broadside and endfire arrays. AiP consists of a $1\times 4$ patch antenna array for broadside radiation and a $1 \times 4$ dipole antenna array for endfire radiation. To miniaturize the patch antenna elements, a multilayer Reactive Impedance Surface (RIS) is embedded between the patch layer and the ground plane. This multilayer RIS idea greatly fits in 5G PCB-stack-up antennas where each stack-up layer essentially requires certain portion of copper area. For the endfire array antenna, miniaturization with bandwidth improvement is achieved by modifying the vertically bent folded dipole antenna (VBFDA) and adding a tightly coupled T-shape side via wall. The AiP achieves a 10 dB return-loss bandwidth of 26.22 to 29.57 GHz and 35.18 to 41.00 GHz for Multilayer RIS Patch Antenna (MLRPA), and 26.40 to 29.74 GHz and 36.65 to 40.72 GHz for VBFDA. The antenna gain is 11.6 dBi for MLRPA and 10.0 dBi for VBFDA.
9 June 2023 in IEEE Transactions on Antennas and Propagation
Verified
Journal Article
Closed access
HKHogyeom Kim
Hogyeom Kim
SOSeongwoog Oh
Seongwoog Oh
SBSeungwoo Bang
Seungwoo Bang
HYHyunjun Yang
Hyunjun Yang
BKByeongjin Kim
Byeongjin Kim
JOJungsuek Oh
Jungsuek Oh
This study presents a new class of independently polarization manipulable liquid-crystal (LC)-based reflective metasurface antenna. To the best of the authors’ knowledge, this study first introduces independent polarization controllability of the LC-based reflective metasurface in mmWave. Two LC layers are embedded into the proposed structure for independent manipulation of the polarization. Isolation topologies, such as rectangular patch shape and metal strip ground, are utilized to enhance polarization purity, achieving compact bias configuration. The independent polarization controllability and antenna performance, such as aperture efficiency, sidelobe level, and beam coverage, are validated as a reflectarray. The proposed antenna has a maximum aperture efficiency of 22.5% and beam coverage of over 120°. In addition, the proposed metasurface is employed to achieve link connectivity as a reconfigurable intelligent surface (RIS) at millimeter-wave 5G. The demonstration confirms a small aperture RIS concept, considering spillover and taper efficiencies.
30 September 2022 in IEEE Transactions on Antennas and Propagation
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Journal Article
Closed access
HKHogyeom Kim
Hogyeom Kim
JKJongyeong Kim
Jongyeong Kim
JOJungsuek Oh
Jungsuek Oh
This communication presents a novel systematic design of a high-aperture-efficiency and 2D beam-scanning nematic liquid-crystal (LC)-based reflectarray (LCRA) that operates in 6G mid-band (7-24 GHz). Despite a 260° phase range, the maximum aperture efficiency is 35.8% at a F/D ratio of 0.58, the highest aperture efficiency at the lowest F/D ratio among LCRAs designed to operate on the mmWave band. The proposed LC-based reflectarray unit cell (LC-RUC) has significantly low reflection loss compared to other LC-RUCs. Also, the bias topology of the proposed LC-RUC makes the LCRA capable of 2D beam-scanning. The beam scanning range of the proposed LCRA is ±50° on the xoz-plane and 0°~65° in the yoz-plane at 9.55 GHz. A 2 × 2 patch array antenna is designed as the feed antenna to achieve small F/D ratio system and ease of optimization. When designing the feed antenna, the number of elements or the element spacing is considered to achieve high feed efficiency. Additionally, the fabricated planar feed antenna can be easily integrated with a 3D printed jig in which the focal length can be adjusted for optimization. The lowest sidelobe level of the proposed LCRA is -15.5 dB.
6 August 2020 in IEEE Antennas and Wireless Propagation Letters
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Journal Article
Closed access
JKJaehoon Kim
Jaehoon Kim
JOJungsuek Oh
Jungsuek Oh
This paper presents a novel reconfigurable microstrip antenna with a frequency of 28 GHz and an embedded liquid crystal (LC). First, a novel fabrication process that employs a heat press machine is developed. It is validated that the proposed stacked topology achieves a wide tunable range of resonant frequency. In addition, a simple bias configuration is achieved by connecting the bias position to the middle of the patch where RF potential is zero. The proposed antenna adopts a three-layer stacked PCB structure to render a cavity in which the LC is injected. The bottom patch of the top substrate is designed to contact the LC, and thus, it simultaneously functions as a DC bias electrode and a radiating element. In addition, the additional patch on the top of the PCB structure is tuned to enhance gain. Compared to the simulated performance of a prior LC-based antenna, the tunable range of the resonant frequency is improved by more than three times at a center frequency of 28 GHz and the peak radiation efficiency is improved by up to 17%. Furthermore, the area (252 mm2) of the proposed LC-based antenna is 40% of the area of the prior LC-based antenna (625 mm2)
21 August 2023 in IEEE Transactions on Antennas and Propagation
Verified
Journal Article
Closed access
BKByeongjin Kim
Byeongjin Kim
JOJungsuek Oh
Jungsuek Oh
This communication presents a single-glass-layer optically transparent transmitarray (TTA) with high aperture efficiency at millimeter-wave (mmWave) 5G band. When designing a transmitarray (TA), the more metal and dielectric layers are used, the easier it is to increase the aperture efficiency. However, if the TTA is designed, the fewer metal and dielectric layers, the more advantageous it is in terms of optical transparency (OT). Therefore, only a single glass layer was chosen to design a TTA with high OT. The novel analysis technique was applied to obtain the theoretical transmission response of the single substrate unit cell (UC) and to obtain impedance information to quickly design UCs by combining circuit analysis. Then, the aperture efficiency was increased using two methods: 1) two types of double resonance UCs were combined and 2) oblique incidence on the UCs on the edge of TA aperture was considered. The designed TA was converted into the TTA, which satisfies the advanced OT guidelines proposed in this communication. The fabricated TTA has a focal length (F) to dimension (D) ratio of 1.2, exhibiting simulated and measured aperture efficiencies of 51.1% and 45.3%.
23 March 2018 in IEEE Antennas and Wireless Propagation Letters
Verified
Journal Article
Closed access
EKEugean Kim
Eugean Kim
SKSeung-Tae Ko
Seung-Tae Ko
YLYoung Ju Lee
Young Ju Lee
JOJungsuek Oh
Jungsuek Oh