Nathan Chordas-Ewell

Research

My work mostly focuses on composite right/left-handed (CRLH) metamaterial structures, both radiating and non-radiating. I also have dabbled in radar, rectifiers, intelligent reconfigurable surfaces (IRS), and other projects.

These are also listed on ORCID and ResearchGate.

Journal Articles

  1. [J1]N. Chordas-Ewell, Z. Li, and J. H. Choi, “Negative Resistance Enabled Amplifying CRLH Transmission Lines With Uniform Insertion Gain,” in IEEE Microwave and Wireless Technology Letters, vol. 36, no. 5, pp. 761–764, May 2026, doi: 10.1109/LMWT.2026.3655243.
  2. [J2]Z. Li et al., “A W-Band Frequency-Scanning Leaky Wave Antenna Based on a Composite Right/Left-Handed Waveguide for Rapid Beam Scanning,” in IEEE Transactions on Antennas and Propagation, vol. 73, no. 12, pp. 10135–10147, Dec. 2025, doi: 10.1109/TAP.2025.3608502.

Conference Papers

  1. [C1]N. Chordas-Ewell and J. H. Choi, “CRLH Negative Order Resonant Antenna with Gain Enhancement Using Reflection-Type Amplifier,” 2026 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting (AP-S/USNC-URSI), Detroit, MI, USA, 2026, doi: 10.1109/ap-s/usnc-ursi60190.2026.11675576.
  2. [C2]K. Chang, Y. Tan, Z. Li, N. Chordas-Ewell, J. E. Kang, and J. H. Choi, “Wideband Adaptive Impedance Transforming Network Enhanced Tunable Phase-Shifter/Amplifier Chain for Intelligent Reflecting Surface Applications,” 2026 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting (AP-S/USNC-URSI), Detroit, MI, USA, 2026, doi: 10.1109/ap-s/usnc-ursi60190.2026.11675556.
  3. [C3]K. Chang, Z. Li, N. Chordas-Ewell, and J. H. Choi, “Reflecting Surface Based on Miniaturized CRLH Inspired True Time Delay Line,” 2025 IEEE International Symposium on Antennas and Propagation and ITNC-USNC-URSI Radio Science Meeting, Ottawa, Canada, 2025, doi: 10.1109/ap-s/cnc-usnc-ursi55537.2025.11266846.
  4. [C4]N. Qadeer, Z. Li, N. Chordas-Ewell, and J. H. Choi, “Active CRLH-Based Antenna Feed Network for Enhanced Pattern Reconfigurability,” 2025 IEEE International Symposium on Antennas and Propagation and ITNC-USNC-URSI Radio Science Meeting, Ottawa, Canada, 2025, doi: 10.1109/ap-s/cnc-usnc-ursi55537.2025.11266310.
  5. [C5]N. Chordas-Ewell, M. A. K. Khan, P. Q. Liu, and J. H. Choi, “Phase Tunable Liquid Metal Reflecting Element for Reconfigurable Reflectarrays,” 2025 IEEE International Symposium on Antennas and Propagation and ITNC-USNC-URSI Radio Science Meeting, Ottawa, Canada, 2025, doi: 10.1109/ap-s/cnc-usnc-ursi55537.2025.11266316.
  6. [C6]Z. Li, N. Chordas-Ewell, and J. H. Choi, “Amplifying CRLH Delay Line for Frequency Scanning Reflectarrays,” 2024 IEEE International Symposium on Antennas and Propagation and ITNC-USNC-URSI Radio Science Meeting, Florence, Italy, 2024, doi: 10.1109/ap-s/inc-usnc-ursi52054.2024.10687191.
  7. [C7]N. Chordas-Ewell, Z. Li, J. H. Choi, D. Ren, and R. Wu, “A W-band Rectifier Design Based on GCPW,” 2022 IEEE/MTT-S International Microwave Symposium - IMS 2022, Denver, CO, USA, 2022, doi: 10.1109/ims37962.2022.9865547.
  8. [C8]K. Xu, N. Chordas-Ewell, Z. Li, and J. H. Choi, “Frequency Scanning Reflectarray Based on Composite Right/Left-Handed Transmission Lines,” 2021 IEEE MTT-S International Microwave Symposium (IMS), Atlanta, GA, USA, 2021, doi: 10.1109/ims19712.2021.9575017.
  9. [C9]Z. Li et al., “Stripline-Based W-Band Frequency Scanning Composite Right/Left-Handed Leaky-Wave Antenna with a Tapered Aperture for Narrow Beamwidth,” 2021 IEEE MTT-S International Microwave Symposium (IMS), Atlanta, GA, USA, 2021, doi: 10.1109/ims19712.2021.9574871.
  10. [C10]Z. Li, K. Xu, N. Chordas-Ewell, D. Ren, J. H. Choi, and R. Wu, “Via-Less Waveguide-to-Stripline Transition Using 2D Electromagnetic Bandgap Structure,” 2020 50th European Microwave Conference (EuMC), Utrecht, Netherlands, 2021, doi: 10.23919/eumc48046.2021.9338057.
  11. [C11]N. Chordas-Ewell, K. Xu, R. Kadlimatti, A. T. Fam, and J. H. Choi, “Vibrating Antenna Doppler Radar,” 2020 17th European Radar Conference (EuRAD), Utrecht, Netherlands, 2021, doi: 10.1109/eurad48048.2021.00069.
  12. [C12]K. Xu, N. Chordas-Ewell, and J. H. Choi, “Planar Vertically Polarized Quasi-Yagi Antennas Using Magnetic Current Loops,” 2019 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting, Atlanta, GA, USA, 2019, doi: 10.1109/apusncursinrsm.2019.8889312.