Koohi Research Group (KRG)

kHz to THz ยท Materials to Systems

Publications

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Patents Journal Articles Conference Papers

Granted U.S. Patents 3

  1. A. Mortazawi and M. Z. Koohi, “Bulk acoustic wave resonators employing materials with piezoelectric and negative piezoelectric coefficients,” U.S. Patent 12,206,388, Jan. 2025
  2. N. Khlat, M. Z. Koohi, and P. Stokes, “Tunable ferroelectric acoustic resonator structure,” U.S. Patent 12,525,955, 2026
  3. N. Khlat and M. Z. Koohi, “Tunable ferroelectric acoustic resonator structure,” U.S. Patent 12,489,420, 2025

Patent Applications

  1. M. Z. Koohi, G. Fattinger, M. AlJoumayly, and J. S. Sadhu, “Bulk acoustic wave resonators with tunable electromechanical coupling,” U.S. Patent App. 18/150,614, 2023
  2. M. Z. Koohi, G. Fattinger, P. Stokes, R. Rothemund, J. S. Sadhu, and I. Veres, “Acoustic wave resonator with low/zero-electromechanical coupling at border region,” U.S. Patent App. 18/150,621, 2023
  3. M. Z. Koohi, A. Tag, M. Schaefer, R. Rothemund, and J. S. Sadhu, “Acoustic wave resonator using multilayer transduction materials with low/zero coupling border region,” U.S. Patent App. 18/150,627, 2023
  4. M. Z. Koohi and P. Stokes, “Zero-coupling border region for BAW resonators using antiparallel polarization,” U.S. Patent App. 19/207,731, 2025
  5. M. Z. Koohi, N. Khlat, and P. Stokes, “Tunable capacitor,” U.S. Patent App. 18/383,118, 2024
  6. M. Z. Koohi and G. Fattinger, “Reconfigurable acoustic wave resonators and filters,” U.S. Patent App. 18/371,159, 2024

Journal Articles 8

  1. M. Z. Koohi and A. Mortazawi, “Negative piezoelectric-based electric-field-actuated mode-switchable multilayer ferroelectric FBARs for selective control of harmonic resonances without degrading Keff2,” IEEE Trans. Ultrason., Ferroelectr., Freq. Control, vol. 67, no. 9, 2020
  2. M. Z. Koohi and A. Mortazawi, “Reconfigurable radios employing ferroelectrics: Recent progress on reconfigurable RF acoustic devices based on thin-film ferroelectric barium strontium titanate,” IEEE Microwave Magazine, vol. 21, no. 5, pp. 120–135, 2020
  3. M. Z. Koohi, S. Nam, and A. Mortazawi, “Intrinsically switchable and bandwidth reconfigurable ferroelectric bulk acoustic wave filters,” IEEE Trans. Ultrason., Ferroelectr., Freq. Control, vol. 67, 2020
  4. M. Z. Koohi, S. Lee, and A. Mortazawi, “Compact intrinsically switchable FBAR filters utilizing ferroelectric BST,” IEEE Trans. Ultrason., Ferroelectr., Freq. Control, vol. 65, no. 8, 2018
  5. M. Z. Koohi and A. Mortazawi, “Intrinsically switchable filter bank employing ferroelectric barium strontium titanate,” IEEE Trans. Microw. Theory Techn., vol. 66, no. 12, pp. 5501–5507, 2018
  6. S. Nam, M. Z. Koohi, W. Peng, and A. Mortazawi, “A switchless quad-band filter bank based on ferroelectric BST FBARs,” IEEE Microw. Wireless Compon. Lett., vol. 31, no. 6, pp. 662–665, 2021
  7. W. Peng, M. Z. Koohi, S. Nam, and A. Mortazawi, “Phenomenological circuit modeling of ferroelectric-driven bulk acoustic wave resonators,” IEEE Trans. Microw. Theory Techn., vol. 70, no. 1, pp. 919–925, 2022
  8. M. Z. Koohi and M. Neshat, “Evaluation of graphene-based terahertz photoconductive antennas,” Scientia Iranica, vol. 22, no. 3, pp. 1299–1305, 2015

Conference Papers 20

  1. A. Hammami, A. K. Hamdan, and M. Koohi, “Multilayer multipin ferroelectric devices for programmable acoustic wave filters,” IEEE MTT-S Int. Conf. Microwave Acoustics & Mechanics (IC-MAM), 2026
  2. A. Tag, M. Koohi, M. Schaefer, and J. Sadhu, “Advances in BAW technology enabling 5G NR and WiFi6E,” IEEE UFFC Joint Symposium (UFFC-JS), 2024
  3. H. Desai, M. Z. Koohi, and A. Mortazawi, “SPST acoustic switch based on poled ferroelectrics,” IEEE MTT-S Int. Microwave Symp. (IMS), pp. 38–41, 2024
  4. A. Tag, M. Schaefer, J. Sadhu, A. Tajic, P. Stokes, M. Koohi, W. Yusuf et al., “Next generation of BAW: The new benchmark for RF acoustic technologies,” IEEE Int. Ultrasonics Symp. (IUS), 2022
  5. W. Peng, M. Z. Koohi, S. Nam, and A. Mortazawi, “Physics-based modeling of electrostriction-based BAW resonators,” IEEE MTT-S Int. Microwave Symp. (IMS), pp. 214–217, 2021
  6. M. Z. Koohi, W. Peng, and A. Mortazawi, “An intrinsically switchable balanced ferroelectric FBAR filter at 2 GHz,” IEEE MTT-S Int. Microwave Symp. (IMS), pp. 131–134, 2020
  7. M. Z. Koohi and A. Mortazawi, “Switched-mode thin-film bulk acoustic wave resonators,” IEEE MTT-S Int. Microwave Symp. (IMS), pp. 528–531, 2019
  8. M. Z. Koohi, S. Nam, and A. Mortazawi, “Intrinsically switchable miniature ferroelectric stacked crystal filters,” IEEE MTT-S Int. Microwave Symp. (IMS), pp. 661–664, 2019
  9. M. Z. Koohi, S. Nam, and A. Mortazawi, “Intrinsically switchable and bandwidth reconfigurable FBAR filter employing electrostriction in ferroelectric BST,” IEEE MTT-S Int. Microwave Symp. (IMS), pp. 743–745, 2018
  10. M. Z. Koohi and A. Mortazawi, “A compact intrinsically switchable filter bank employing multifunctional ferroelectric BST,” IEEE MTT-S Int. Microwave Symp. (IMS), pp. 849–851, 2018
  11. M. Z. Koohi and A. Mortazawi, “On the linearity of BST thin-film bulk acoustic resonators,” IEEE MTT-S Int. Microwave Workshop Series on Advanced Materials and Processes (IMWS-AMP), 2018
  12. M. Z. Koohi and A. Mortazawi, “Linearity measurements of intrinsically switchable BST FBAR filters,” 48th European Microwave Conf. (EuMC), pp. 830–832, 2018
  13. M. Z. Koohi, S. Lee, and A. Mortazawi, “Fabrication of a low-insertion-loss intrinsically switchable BAW filter based on BST FBARs,” IEEE MTT-S Int. Microwave Symp. (IMS), pp. 1480–1483, 2017
  14. M. Z. Koohi, S. Lee, and A. Mortazawi, “High Qm×Kt2 intrinsically switchable BST thin-film bulk acoustic resonators,” IEEE MTT-S Int. Microwave Symp. (IMS), pp. 296–299, 2017
  15. M. Z. Koohi and A. Mortazawi, “BST thin-film bulk acoustic resonator optimization for un-cooled IR sensor applications,” 47th European Microwave Conf. (EuMC), pp. 328–330, 2017
  16. M. Z. Koohi, S. Lee, and A. Mortazawi, “Design of BST-on-Si composite FBARs for switchable BAW filter applications,” 46th European Microwave Conf. (EuMC), pp. 1003–1006, 2016
  17. S. Lee, M. Z. Koohi, and A. Mortazawi, “Lateral-wave spurious-mode elimination in switchable ferroelectric BST-on-Si composite FBARs,” IEEE MTT-S Int. Microwave Symp. (IMS), 2016
  18. M. Z. Koohi, S. Lee, V. Lee, S. A. Sis, and A. Mortazawi, “Un-cooled resonant IR detectors based on barium strontium titanate switchable FBARs,” European Microwave Conf. (EuMC), pp. 948–951, 2015
  19. S. Lee, M. Z. Koohi, S. A. Sis, V. Lee, and A. Mortazawi, “Temperature-dependent characteristics of intrinsically switchable ferroelectric composite FBARs,” IEEE MTT-S Int. Microwave Symp. (IMS), 2015
  20. M. Z. Koohi and M. Neshat, “Antenna efficiency in graphene-based THz photoconductive antennas,” 22nd Iranian Conf. on Electrical Engineering (ICEE), pp. 1587–1590, 2014