Publications

[47] Y. Lee, H.E. Choi, M.C. Kim, K. Bhotkar, K.C. Park, S.G. Jeon, and E.M. Choi* "Physical Interpretation of Field Emission Behavior in Patterned Samples via Simulation-Validated Models," IEEE Transactions on Electron Devices, vol. 72, iss. 12, DOI: 10.1109/TED.2025.3625920 (2025).

[46] Y.H. Jin, J.H. Han, J. Park, M.C. Kim, S.H. Seok, Y. Chae, Y. Sim, S. Seo, H. Lee, J. Wang, J. Wang, S.Jang, J. Han, H.U. Yeo, S.H. Park, E.M. Choi, T. Kim, and S.Y. Kwon* "Water- and oxidation-resistant MXenes for advanced electromagnetic interference shielding applications," InfoMat, https://doi.org/10.1002/inf2.70034 (2025).

[45] J.H. Han, J. Park, M.C. Kim, S. Lee, J.M. Heo,Y.H. Jin, Y. Chae, J. Han, J. Wang, S.H. Seok, Y. Sim, G. Byun, G.D. Lee*, E.M. Choi*, and S.Y. Kwon* "Ultrahigh Conductive MXene Films for Broadband Electromagnetic Interference Shielding," Advanced Materials, 2502443, DOI: 10.1002/adma.202502443 (2025).

[44] Y. Chae, S.H. Seok, W. Sim, J.H. Han, J.E. Park Y. Jang, M.C. Kim, Y.H. Jin, E.M. Choi, Z.H. Lee, and S.Y. Kwon* "Scalable synthesis of high-purity Ti4N3Tx MXene via saturated salt solution (S3) etching," Advanced Powder Materials 4, 100334, https://doi.org/10.1016/j.apmate.2025.100334 (2025).

[43] J. Lee, H.E. Choi, W.Choi, and E.M. Choi*, "Advanced Bragg Resonator Integration for Enhanced Bandwidth and Stability in G-band TWT with Staggered Double Vane Structure," IEEE Transactions on Electron Devices, Vol. 72, Iss. 1, pp. 459-466, January, DOI: 10.1109/TED.2024.3509384, (2025).

[42] H.E. Choi, W. Choi, J. Lee, and E.M. Choi*, "Experimental Investigation of a Dual-beam Traveling Wave Tube," IEEE Transactions on Electron Devices, vol. 71, iss. 7 pp. 4336-4341, DOI: 10.1109/TED.2024.3405398 (2024).

[41] E. Baijukya, J. H. Lim, and E. M. Choi*, "Machine Learning Guided Alignment System for a W-band Higher-Order Mode Generator," IEEE Microwave and Wireless Technology Letters, vol. 34, iss. 5 pp. 471-473, DOI: 10.1109/LMWT.2024.3371646 (2024).

[40] H.E. Choi, and E.M. Choi*, "High-precision complex permittivity measurement of high loss dielectric materials using a geometrical gap in millimeter-wave frequency," Journal of Infrared, Millimeter, and Terahertz Waves, vol. 45, p.97-115 (2024).

[39] S. J. Moon, D. H. Yu, and E. M. Choi*, "High-Power Gyrotron Mode Discrimination of Orbital Angular Momentum Beams Using Double Slit Interference" IEEE Transactions on Plasma Science 10.1109/TPS.2023.3343750 (2023).

[38] A. Sawant, I.G. Lee, and E.M. Choi*, "Amplitude Non-uniformity of Millimeter Wave Vortex Beams Generated by Transmissive Structures" IEEE Transactions on Antennas and Propagation DOI: 10.1109/TAP.2022.3140520 (2022).

[37] T.G. Han, Y.M. Seo, and E.M. Choi*, "Significant Reduction of Resonant Frequency by Multi-Layered Dielectric Material Loaded Coaxial Cavity for Microwave Heating" Journal of Electromagnetic Engineering and Science 22(1):1-7. (DOI: https://doi.org/10.26866/jees.2022.1.r.53) (2022).

[36] W. Choi, I. Lee, J. Shin, and E.M. Choi*, "Stability Analysis of 300 GHz Sheet Electron Beam Transport in a Periodic Rectangular Quadrupole" IEEE Transactions on Plasma Science DOI: 10.1109/TPS.2021.3058375 (2021).

[35] I. Lee, A. Sawant, J. Shin, and E.M. Choi*, "Accurate Gyrotron Performance Prediction Based on Full 3-D Magnetic Field and Electron Beam Information Altered by Nonideal Factors" IEEE Transactions on Electron Devices Volume: 68, Issue: 3, DOI: 10.1109/TED.2021.3053512, March (2021).

[34] I. Lee, A. Sawant, and E. M. Choi*, "High-Directivity Orbital Angular Momentum Antenna for Millimeter-Wave Wireless Communications" IEEE Transactions on Antennas and Propagation, vol. 69, no. 7, pp. 4189-4194, July 2021, DOI: 10.1109/TAP.2020.3044602. (2021).

[33] A. Sawant, I. Lee, B.C. Jung, and E.M. Choi*, "Ultimate Capacity Analysis of Orbital Angular Momentum Channels" IEEE Wireless Communications, DOI: 10.1109/MWC.001.2000258 (2020).

[32] H. Chung, D. Kim, A. Sawant, I. Lee, E.M. Choi, and J. Lee*, "Generation of E-band metasurface-based vortex beam with reduced divergence angle" Scientific Reports 10, 8289 (2020).

[31] A.Sawant, D.Kwak, I.Lee, M.Chung*, and E.M.Choi*, "Stand-off Radiation Detection Techniques" Review of Scientific Instruments 91, 071501; DOI: 10.1063/1.5134088 (2020).

[30] M. S. Choe, A. Sawant, and E. M. Choi*, "High-Density Plasma Diagnosis Using Quasi-Optical Millimeter-Wave Systems" IEEE Transactions on Plasma Science DOI: 10.1109/TPS.2020.3026016 (2020).

[29] H. E. Choi, W. Choi, E. I. Simakov, M. Zuboraj, B. E. Carlsten, and E. M.Choi*, "Error Tolerant Method of Dielectric Permittivity Determination Using a TE01 Mode in a Circular Waveguide at the W-Band" IEEE Transactions on Microwave Theory and Techniques Vol. 68, No. 2, pp 808–815, Dec (2019).

[28] R. Patel, M.W.Ryu, M.S.Choe, E.M.Choi, K.R.Kim, and K.J.Han*, "Monolithic Circular Transistor-Antenna Design for High Performance Plasmonic Millimeter-Wave Detectors" IEEE Transactions on Microwave Theory and Techniques Vol. 68, No. 2, pp 808–815, Dec (2019).

[27] A. Sawant, and E. M. Choi*, "Development of the full package of gyrotron simulation code" Journal of the Korean Physical Society Vol.73, Iss.11, pp 1750–1759, December (2018).

[26] I. Lee and E. M. Choi*, "마이크로 공정을 이용한 테라헤르츠 첨단 진공 소자 개발 현황 및 향후 전망" 한국전자파학회지 (2018).

[25] I. G. Lee, W. Choi, J. Shin, and E. M. Choi*, "Microscopic Analyses of Electrical Conductivity of Micromachined-Folded Waveguides Based on Surface Roughness Measurement for Terahertz Vacuum Electron Devices" IEEE Transactions on Terahertz Science and Technology vol.8, iss. 6, pp. 710-718, November (2018).

[24] I. G. Lee, A. Sawant, W. Choi, J. W. Shin, and E. M. Choi*, "Self-Driving, Energy-Recirculating Micromachined G-Band Folded Waveguide Traveling-Wave Tube" IEEE Transactions on Electron Devices vol. 65, iss. 8, pp. 3492-3499 (2018).

[23] I. G. Lee, A. Sawant, M. S. Choe, D. J. Lee, and E. M. Choi*, "Accurate Identification of Whispering Gallery Mode Patterns of Gyrotron with Stabilized Electro-Optic Imaging System" Physics of Plasmas 25, 013116 (2018).

[22] A. Sawant, and E. M. Choi*, "Competition-free second harmonic mode THz orbital angular momentum gyrotron with dual-mode operation by a perturbed cavity" Physics of Plasmas 24, 113109 (2017).

[21] A. Sawant, M. S. Choe, M. Thumm, and E. M. Choi*, "Orbital Angular Momentum (OAM) of Rotating Modes Driven by Electrons in Electron Cyclotron Masers" Scientific Reports 7, 3372 (2017).

[20] W. Choi, I. G. Lee, and E. M. Choi*, "Design and Fabrication of a 300 GHz Modified Sine Waveguide Traveling-Wave Tube Using a Nano Computer Numerical Control Machine" IEEE Transactions on Electron Devices vol. 64, iss. 7, pp. 2955-2962 (2017).

[19] D. S. Kim, D. H. Yu, A. Sawant, M. S. Choe, I. G. Lee, S. G. Kim, and E. M. Choi*, "Remote Detection of Radioactive Material using High-Power Pulsed Electromagnetic Radiation" Nature Communications 8, 15394 (2017).

[18] M. S. Choe , A. Sawant , K. S. Lee , N. E. Yu*, and  E. M. Choi*, "Measuring the carrier lifetime by using a quasi-optical millimeter- and THz-wave system" Applied Physics Letters 110, 074101 (2017).

[17] A. Sawant, D.H. Yu, D.S. Kim, M.S. Choe, and E.M. Choi*, "Generation and validation of topological charges of high-power gyrotron orbital angular momentum beams from phase retrieval algorithm" IEEE Transactions on Terahertz Science and Technology, vol. 7, iss 2, pp. 164-171 (2017).

[16] D. Gamzina, L. Himes, R. Barchfeld, Y. Zheng, B. Popovic, C. Paoloni, E. M. Choi, and N. C. Luhmann*, "Nano-CNC machining of sub-THz vacuum electron devices" IEEE Transactions on Electron Devices, vol. 63, Iss. 10, pp. 4067-4073 (2016).

[15] D.S. Kim, M.S. Choe, D.H. Yu, A. Sawant, and E.M. Choi*, "A Method for Temporal Pulse Shortening of High Power Millimeter Waves Using Plasma Breakdown" IEEE Transactions on Plasma Science, Vol. 44, Iss. 8, pp. 1320-1323 (2016).

[14] D. S. Km, S. G. Kim, A. Sawant, D. Yu, M. S. Choe, and E. M. Choi*, "Study on Statistical Breakdown Delay Time in Argon Gas Using a W-band Millimeter-wave Gyrotron" Physics of Plasmas 23, 043505 (2016).

[13] S. G. Kim, A. Sawant, I. Lee, D. S. Kim,  M. S. Choe, J. H. Won, J. H. Kim, J. H. So, W. J, and E. M. Choi*, "System development and performance testing of a W-band gyrotron" Journal of Infrared, Millimeter, and Terahertz Waves vol. 37, issue 3, pp. 209-229 (2016).

[12] S. G. Kim, J. H. Kim, D. S. Kim, J. Won, W. S. Lee, J. Yang, and E. M. Choi*, "Direct real-time power measurement of a high-power electron cyclotron maser by a simple one-point Schottky detector signal" IEEE Transactions on Terahertz Science and Technology vol. 5, no. 5, pp. 779-785 (2015).

[11] I. Lee, D. J. Lee*, and E. M. Choi*, "In-situ endoscopic observation of higher-order mode conversion in a microwave mode converter based on an electro-optic probe system" Optics Express vol. 22, Issue 22, pp.27542-27552 (2014).

[10] A. Sawant, S. G. Kim, M. C. Lin, J. H. Kim, Y. J. Hong, J. H. So and E. M. Choi*, "Validation of 3D time domain particle-in-cell simulations for cold testing a W-band gyrotron cavity" IEEE Transactions on Plasma Science vol. 42, no. 12, pp.3989-3995 (2014).

[9] S. G. Kim, D. S. Kim, M. S. Choe, W. S. Lee, J. H. So and E. M. Choi*, "Cold testing a quasi-optical gyrotron mode converter using a higher-order linearly polarized mode generator" Review of Scientific Instruments 85, 104709 (2014).

[8] K. H. Kim, M. S. Choe, W. S. Lee, J. H. So, and E. M. Choi*, "Near field pattern of large aperture higher order mode generator using back propagated fields in free space" IEEE Transactions on Plasma Science vol. 42, no. 4, pp.937-943 (2014).

[7] M. S. Choe, and E. M. Choi*, "Higher-order mode generation in the millimeter wave regime by a directly launched fundamental mode" Microwave and Optical Technology Letters vol. 56, issue 7, pp. 1648-1651 (2014).

[6] M. S. Choe, K. H. Kim, and E. M. Choi*, "A comprehensive analysis of a TE11 to HE11 mode converter for an oversized F-band corrugated waveguide," Journal of Electromagnetic Waves and Applications vol. 27, Issue 17, pp 2221-2238 (2013).

[5] D. S. Kim, W. S. Lee, J. H. So, and E. M. Choi *, "Numerical estimation on free electrons generated by shielded radioactive materials under various gaseous environments," AIP Advances 3, 062109 (2013).

[4] J. K. Ahn et al., "Overview of the KoRIA Facility for Rare Isotope Beams," Few-body Systems (2012).

[2] S. G. Kim, K. H. Kim, H. S. Jung, H. Cho, and E. M. Choi*, "Frequency splitting of a multi-layered electric ring resonator," Journal of Applied Physics 110, 013105 (2011).

[1] D. S. Tax*, E. M. Choi, I. Mastovsky, J. M. Neilson, M. A. Shapiro, J. R. Sirigiri, R. J. Temkin, and A. C. Torrezan*, "Experimental Results on a 1.5 MW, 110 GHz Gyrotron with a Smooth Mirror Mode Converter" Journal of Infrared, Millimeter, and Terahertz Waves Vol. 32, pp.358-370 (2011).