About my research

⚫ General Research Interest

Liquid crystals (LCs) Applied Technology, Millimeter-Wave, 5G/6G, RF, Antenna, Artificial Intelligence (AI) technology

⚫ Current Research Interest

Improving the performance of liquid-crystals phase shifter (LCPS), Stretchable & Flexible electronics, Optically steerable RF devices,  Efficient design of smart devices using drop-on-demand printing, Liquid Crystal Printing

Language: Korean (Native), English (Advanced)

Programming Language: C, Python, Matlab, Tensorflow, Pytorch

Simulation Tool: TechWiz (Sanai Systems), Ansys HFSS, Advanced Design System (ADS, Keysight)

Liquid Crystals-based RF applications

Liquid crystals (LCs) technology, long established in the visible light spectrum, particularly within the display industry, is now gaining significant attention in the realm of high-frequency microwave (MW) and millimeter-wave (mmWave) applications. This shift is driven by the rapid advancements in communication technology, where LCs offer promising characteristics such as tunability, continuous tuning, low losses, and cost-effectiveness. These attributes make LCs highly suitable for integration into next-generation communication systems.

However, to fully realize the potential of LCs in advancing future communication technologies, a narrow focus on traditional radio-frequency (RF) technology is insufficient. The true potential of LCs in MW and mmWave applications can only be unlocked through a comprehensive approach that includes novel structural designs, optimization of microwave engineering, and a deep understanding of materials science.

Integrating LCs into advanced RF devices requires not just expertise in RF engineering but also innovative approaches in materials engineering. By exploring new materials and structural configurations, we can enhance the performance of LC-based devices, making them more efficient and adaptable for next-generation satellite and terrestrial communication systems. This holistic approach is crucial for achieving the maximum performance of LC-based technologies in the rapidly evolving landscape of high-frequency communication.

Furthermore, the continued development and refinement of LC technology for MW and mmWave applications could lead to breakthroughs in various fields, including satellite communications, radar systems, and wireless networks. By leveraging the unique properties of LCs and pushing the boundaries of both MW engineering and materials science, we can drive significant advancements in the performance, efficiency, and affordability of communication technologies in the future.

▪ 2020. 9 ~ Current (Ongoing) 

Researching Participant in Collaboration Project with NEPES in Korea, JNC Corporation in Japan. 

Project: 액정 안테나용 액정 개발 & 5G 대역 이상의 액정 안테나 상용화 (Development of liquid crystals (LCs) for LC-based RF applications & Commercialization of LC antenna over 5G-band)

▪ 2021. 9 ~ Current (Ongoing) 

Researching Participant in Collaboration Project with Seoul National University (Prof. Oh Group (WFL Lab)), and Pohang University of Science and Technology (Prof. Hong Group (MADs LAb). 

Project: Sub-THz 통신용 자가 조정 가능 일체형 능동 전자 표면 원천 기술 (CORE: Cognitive Organic Reconfigurable Electronics for Sub-THz 6G), Funded by Samsung Science & Technology Foundation (삼성미래기술육성사업, Project number: SRFCTE2013)

▪ 2022. 8 ~ 2022. 12

Researching Participant in Collaboration Project with Pohang University of Science and Technology (Prof. Jung Group (BIPP Lab)) and Optiple Corporation in Korea. 

Project: Inkjet printing 기술을 활용한 액정 기반의 휘어지는 Film형 안테나 및 RF 소자 개발 (Development of flexible liquid crystals-based RF applications using inkjet printing technology)

▪ 2023. 12 ~ Current (Ongoing)

Project Lead for designing advanced RF devices using Drop on demand (DoD) printing.

Project: Designs and fabricates liquid crystal phased array systems using drop-on-demand printing.

Liquid Crystals-based Advanced Smart Windows

Liquid crystals (LCs) are well-known materials that play a crucial role in the design of smart windows, primarily by regulating refractive index mismatching. This unique property makes LCs highly effective in controlling light transmission, leading to the development of various types of LC-based smart windows, such as Polymer Dispersed Liquid Crystals (PDLCs), Polymer Stabilized Liquid Crystals (PSLCs), and Polymer Stabilized Cholesteric Liquid Crystals (PSCLCs). These technologies have progressed to the point of commercialization, demonstrating their practicality and effectiveness in real-world applications.

Despite this success, there remains significant potential to enhance the performance and functionality of LC-based smart windows further. By employing advanced material design techniques, we can develop new formulations that optimize light modulation, durability, and energy efficiency. These improvements could lead to the creation of smart windows with even greater control over light and heat, thereby increasing their applicability in diverse environments, from residential buildings to commercial and industrial spaces.

Beyond their use in smart windows, liquid crystals offer a wide range of applications in other fields. For example, they can be utilized in augmented reality (AR) and virtual reality (VR) optics, where precise control of light and image clarity is essential. Additionally, LC technology can contribute to energy-saving solutions by reducing the need for artificial lighting and climate control, thus lowering energy consumption in buildings.

Moreover, the versatility of liquid crystals extends to the display industry, where they are already a fundamental component in LCD screens. However, with continued innovation, LCs could pave the way for new types of displays that offer enhanced brightness, contrast, and viewing angles. In fact, the potential applications of liquid crystal technology are vast, ranging from regulating light transmission to contributing to advanced optical devices and energy-efficient systems. By leveraging cutting-edge material design and engineering approaches, the future of LC-based technologies promises even broader and more impactful uses.

Lee, J. H., Ma, J. S., An, C. H., Lee, G. H., & Oh, S. W. (2024). Advanced Light: Liquid Crystals‐Based Ultra‐Broadband Polarization Rotator for Functional Smart Devices. Small Methods, 8(3), 2301106. 

Smart Material Simulation and Medeling

Smart materials are becoming increasingly important in modern research, as material innovation often serves as the foundation for breakthroughs across various fields. In my research, I have focused extensively on liquid crystal modeling, exploring a wide range of dopants and their effects on the properties of liquid crystals. My work includes studies on Electrochromic Liquid Crystals (ECLCs), chiral nematics, and blue phase liquid crystals, each tailored for specific applications aimed at driving technological innovation.

In addition to material modeling, my research also delves into the study of topological defects in liquid crystals, such as torons. These defects, which arise from the unique orientational properties of liquid crystals, are not just theoretical curiosities but hold significant potential for practical applications. Understanding and controlling these defects can lead to new ways to manipulate light and other electromagnetic waves, opening up possibilities for advanced optical devices, sensors, and even quantum computing.

By combining the study of liquid crystal phases with the exploration of topological defects, my research contributes to the broader field of smart materials, pushing the boundaries of what is possible in material science and engineering. This integrated approach not only enhances our understanding of liquid crystals but also paves the way for the development of novel applications in areas such as display technology, photonics, and responsive materials. Ultimately, the innovations stemming from these studies have the potential to impact a wide range of industries, from consumer electronics to advanced communication systems.

Zhao, H., Tai, J. S. B., Wu, J. S., & Smalyukh, I. I. (2023). Liquid crystal defect structures with Möbius strip topology. Nature Physics, 19(3), 451-459.