JOURNAL PAPERS

After joining IISc

1.  K. S. Sharma, T.S.R. Akhil, L., K. C. J. Raju, and G. Pillai, “Switchable and Tuneable High-Performance Acoustic Modes in the L-X Band Using Ferroelectric Thin Film on Sapphire” accepted in Nature Microsystems & Nanoengineering 2025

2.  P. Kumar, C. Lakshminarayan, A. Jayaseelan, and G. Pillai, "Tunable phononic frequency combs in curved piezoelectric micromachined ultrasound transducers enabled by 2:1 internal resonance and a ferroelectric thin film," accepted in Journal of Applied Physics, August 2025.

3.  P. Kumar, C. Lakshminarayan, A. Jayaseelan, and G. Pillai, "Evolution of Tunable Phononic Frequency Combs via Three-mode Interaction in Curved Piezoelectric Micromachined Ultrasonic Transducers" in Scientific Reports, vol. 15, no. 16105, April 2025.

4. Z. -Q. Lee, J. Raj, K. Sandeep Sharma, G. Pillai, and M. -H. Li, "Cryogenic Characterization of Low-Loss Thin-Film Lithium Niobate on Sapphire Shear Horizontal Surface Acoustic Wave Devices," in IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, vol. 72, no. 1, pp. 55-63, Jan. 2025.

5. V. Kumar, S. Tiwari, G. Pillai, R. Pratap and S. A. Chandorkar, "Synchronized Opto-Electro-Mechanical Measurements for Estimation of Energy Dissipation in Thin-Film-Piezoelectricon-Substrate MEMS/NEMS Devices," in Journal of Microelectromechanical Systems, vol. 33, no. 6, pp. 793-805, Dec. 2024.

6. P. Kumar, Sahana D, C. Lakshminarayan, A. Jayaseelan, M M Nayak, R. Pratap, and G. Pillai, "Ultrasensitive Pressure Sensor based on an Integrated Circular Piezoelectric MEMS Resonator and Diaphragm Structure" in IEEE Sensors Letters, vol. 7, no. 12, pp. 1-4.

7.  K. S. Bhosale, A. A. Zope, G. Pillai, S.-S. Li, “Tiny-Gap Titanium-Nitride-Composite MEMS Resonator Designs with High Power Handling Capability,” Journal of Microelectromechanical Systems, vol. 32, no. 2, pp. 173-183, 2023.

8.  K. S. Sharma, H.-T. Jen, S.-S. Li, and G. Pillai, "Investigation of Support Transducer Enabled Higher-order Radial Bulk Mode MEMS Resonator and Low Phase Noise Oscillator," Journal of Micromechanics and Microengineering 32, no. 8 (2022): 084004. (Special issue collection of JMM Emerging Leaders 2022).

Before joining IISc

9.  G. Pillai, and S.-S. Li, " Exploration and Realization of Novel High-Q Bulk Modes Using Support Transducer Topology,” Journal of Microelectromechanical Systems 30, no. 5 (2021): 696-702.

10.  G. Pillai, and S.-S. Li, "Controllable Multichannel Acousto-Optic Modulator and Frequency Synthesizer Enabled by Nonlinear MEMS Resonator," Scientific reports, vol. 11, no. 1, pp. 1-13, 2021.

11.  G. Pillai, and S.-S. Li, “Quality Factor Boosting of Bulk Acoustic Wave TPoS Resonators Using Based on a Two-Dimensional Array of High-Q Resonant Tanks,” Applied Physics Letters, vol. 116, no. 16, April 2020.

12.  G. Pillai, and S.-S. Li, "Piezoelectric MEMS Resonators: A Review," IEEE Sensors Journal (Invited Paper), Nov. 2020.

13. C.-H. Weng, G. Pillai, and S.-S. Li, “A Thin-Film Piezoelectric-on-Silicon MEMS Oscillators for Mass Sensing Applications,” IEEE Sensors Journal, March 2020.

14. C.-H. Weng, G. Pillai, and S.-S. Li, “A PM2.5 Sensor Module Based on a TPoS MEMS Oscillator and an Aerosol Impactor,” IEEE Sensors Journal, July 2020.

15.  H.-T. Jen, G. Pillai, S.-I. Liu, and S.-S. Li, "High-Q Support Transducer MEMS Resonators Enabled Low Phase Noise Oscillators," IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, vol. 68, no. 4, pp. 1387-1398, 2020.

16. G. Pillai, A. A. Zope, and S.-S. Li, “Piezoelectric based support transducer design to enable high-performance bulk mode resonators,” IEEE/ASME J. Microelectromech. Syst. (JMEMS), vol. 28, no. 1, pp. 4-19, Feb. 2019.

17. J. Satija, S. Dey, S. Bhattacharya, G. Pillai, and S.-S. Li, "A Chip-Scale Frequency Down-Conversion Realized by MEMS-Based Filter and Local Oscillator," Sensors and Actuators A: Physical, p. 111787, 2019.

18.  M.-H. Li, W. Chiu, C. Chou, G. Pillai, and S.-S. Li, “Conceptual Design of a Resonant Pirani Gauge (RPG) Towards Wide Range Pressure Sensing,” IEEE Sensors Letters, Oct. 2019.

19.  G. Pillai, A. A. Zope, J. M.-L. Tsai, and S.-S. Li, “Design and Optimization of SHF Composite FBAR Resonators,” IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control (T-UFFC), vol. 64, no. 12, pp. 1864-1873, Dec. 2017

CONFERENCES

After joining IISc

1. Linet Thomas C, P. Kumar and G. Pillai, “A Hybrid MEMS - Combining Piezoelectric and Ferroelectric Thin-film Functionalities” IEEE South Asian Ferroelectric Symposium (SAFS) Bengaluru, India, August 5-8, 2025

2. H. Rajput, K. S. Sharma, Sahana D, and G. Pillai, “C- Axis Oriented AlN Thin Films for High Frequency Acoustic Resonator   Applications” IEEE South Asian Ferroelectric Symposium (SAFS) Bengaluru, India, August 5-8, 2025.

3. P. Kumar, C. Lakshminarayan, A. Jayaseelan, and G. Pillai, “Generation of Phononic Frequency Combs via Nonlinear Mode Coupling in Curved Circular Piezoelectric MEMS Resonators,” IEEE South Asian Ferroelectric Symposium (SAFS) Bengaluru, India, August 5-8, 2025.

4. K. S. Sharma, T.S.R. Akhil, L., K. C. J. Raju, and G. Pillai, “Observation of Akhiezer and Landua-Rumer Regimes in the Temperature Dependence of Longitudinal Wave in BST on Sapphire BAW Resonator” IEEE South Asian Ferroelectric Symposium (SAFS) Bengaluru, India, August 5-8, 2025.

5. A. Jeyaseelan, Javed N, G. Pillai, and R. Pratap. “Different textured PZT film grown on Si/Pt substrate”, IEEE-South Asian Ferroelectric Symposium (SAFS) Bengaluru, India, August 5-8, 2025

6. Linet Thomas C, P Kumar, S Khan and G. Pillai, “Novel Fabrication Scheme using Lateral Stacking of Hybrid Piezo/Ferroelectric Thin-Films for MEMS Resonators”, 23rd Int. Conf. On Solid – State Sensors (Transducers 2025), Orlando, Florida, USA, June 29 – July 25, 2025.

7.  R. Jesma. R, K. -W. Tang, S. -S. Li and G. Pillai, "Experimental Study of Q-Boosting in Tpos Resonators using Conventional and Coupled Resonator Architecture," 2025 IEEE 38th International Conference on Micro Electro Mechanical Systems (MEMS), Kaohsiung, Taiwan, 2025, pp. 1169-1172

8. P. Kumar, Linet Thomas, Sahana D, L. N. Chandrashekar, Antony Jeyaseelan, and G. Pillai, “Evolution of Phononic Frequency Combs in Curved Piezoelectric Micromachined Ultrasonic Transducers (PMUTs) Under Single-Tone Actuation”, 2024 IEEE Ultrasonics, Ferroelectrics, and Frequency Control Joint Symposium (UFFC-JS 2024), Taipei, Taiwan, September 22-26, 2024.

9.  S. Bose, R. Jesma, K. S. Sharma and G. Pillai, “Design and Realization of a Fully Differential SAW Filter Architecture for Bandwidth Enhancement,” in Proc. 2024 IEEE Ultrasonics, Ferroelectrics, and Frequency Control Joint Symposium (UFFC-JS), Taipei, Taiwan, 2024, pp. 1–3

10.  P. Kumar, L. N. Chandrashekar, and G. Pillai, “Observation of Phononic Frequency Combs in Circular Piezoelectric MEMS Resonators” Int. Conf. on Micro, Nano, Smart Systems (IC-MNSS 2024), Bengaluru, India, July 9-12, 2024. #

11.  Raeann Jesma R, K.S. Sharma, and G. Pillai, “FEM analysis of Support Transducer Topology for High-Q Piezoelectric MEMS Resonator”, Int. Conf. On Micro, Nano, Smart Systems (IC-MNSS 2024), Bangalore, India, July 9-12, 2024. #

12.  Linet Thomas C, P.Kumar, G. Pillai, “Design of a Hybrid Piezoelectric Material Stack for Piezoelectric Micromachined Ultrasonic Transducer”, Int. Conf. On Micro, Nano, Smart Systems (IC-MNSS 2024), Bangalore, India, July 9-12, 2024. #

13.  K. S. Sharma, T.S.R. Akhil, L. N. Chandrashekar , K. C. J. Raju, and G. Pillai , “Excitation of 105 Quality Factor in a High Overtone Bulk Acoustic Wave Resonator Operating at 5 GHz”, Int. Conf. On Micro, Nano, Smart Systems (IC-MNSS 2024), Bangalore, India, July 9-12, 2024. #

14.  G. Pillai, “Sensor Platform Using Flexural Mode Piezoelectric MEMS Resonators Flexural mode resonators” 19th IEEE International Conference on Nao/Micro Engineered and Molecular Systems (IEEE-NEMS 2024), Kyoto, Japan from May 2 - 5, 2024. #

15.  Sahana D, P. Kumar, L. N. Chandrashekar, A. Jayaseelan, M M Nayak, R. Pratap, and G. Pillai, “Resonant Pressure Sensor for Harsh Environment using Piezoelectric Micromachined Ultrasound Transducer” IEEE South Asian Ultrasonics Symposium 2024. IIT Gandhinagar, India, March 27-29,2024. #

16.  J. Raj, K.S. Sharma, Chandrashekar. L. N, A. Jayaseelan. A, G. Pillai, “Exploring the tunability of acoustic resonator with Sol-gel PZT for Ultra-High Frequency applications”, IEEE South Asian Ultrasonics Symposium 2024. IIT Gandhinagar, India, March 27-29,2024. #

17.  N. Javed, A.Kumar, S.Tiwari, P.Jain, R.Pratap, G.Pillai, “ Effective Packaging of PZT on Silicon microcantilever submerged in liquids for fluid property sensing,” IEEE South Asian Ultrasonics Symposium 2024. IIT Gandhinagar, India, March 27-29,2024. #

18.  Chandrashekar L N, Sahana D, Praveen Kumar, Antony Jeyaseelan, and G. Pillai, “Experimental Validation of a Fabrication Approach Using Intermediate Layer for Ultrasonic Transducers” IEEE South Asian Ultrasonics Symposium 2024. IIT Gandhinagar, India, March 27-29,2024. #

19.  N. Javed, A. Kumar, S. Tiwari, R. Pratap, and G. Pillai, “Dummy device-based feedthrough cancellation for PZT on Silicon microcantilever for viscosity sensing,” IEEE Electron Devices Technol. Manuf. Conf. Strength. Glob. Semicond. EDTM 2024, no. c, pp. 1–3, 2024

20.  K. S. Sharma, A. Ramant, L. N. Chandrasekhar, K. C. J. Raju, and G. Pillai, "Temperature And Bias-Dependent Switch ability And Tuneability Of Very High-Quality Factor GHz Resonators", 37th International Conference on Micro Electro Mechanical Systems | MEMS 2024 | 21-25 January 2024 | Austin, Texas, USA.

21. P. Kumar, Sahana D, C. Lakshminarayan, A. Jayaseelan, M M Nayak, R. Pratap, and G. Pillai, "A Wide-Range Resonant Pressure Sensor With Enhanced Sensitivity Based On An Indirect Coupling Scheme", 37th International Conference on Micro Electro Mechanical Systems | MEMS 2024 | 21-25 January 2024 | Austin, Texas, USA.

22.  P. Kumar, Sahana D, C. Lakshminarayan, A. Jayaseelan, M M Nayak, R. Pratap, and G. Pillai, "Ultrasensitive Pressure Sensor based on an Integrated Circular Piezoelectric MEMS Resonator and Diaphragm Structure", 2nd International IEEE Applied Sensing Conference January 22-24, 2024, in Goa, India. (IEEE SL)

23.  K. -W. Tang, A. A. Zope, Z. -W. Lin, G. Pillai and S. -S.Li, “A Mechanically Coupled Piezoelectric MEMS Filter Based On Support Transducer Topology”, Transducers 2023, Kyoto.

24.  K. S. Sharma, A. Ramant, L. N. Chandrasekhar, K. C. J. Raju, and G. Pillai, “Laterally Coupled BST/Sapphire High Overtone Bulk Acoustic Resonators Exhibiting DC Tunable Comb Filter Response with High Q.f Product” 2023 Joint Conference of the IEEE International Frequency Control Symposium & European Frequency and Time Forum, Tayoma, Japan.

25.  N. Javed, P. Singh, S. Tiwari, P. Jain, R. Pratap, and G. Pillai, “PZT-Based Multi-Mode Cantilever for Viscosity Sensing” 2023 Joint Conference of the IEEE International Frequency Control Symposium & European Frequency and Time Forum, Tayoma, Japan.

26.  K. S. Sharma, J. P. Goud, K. C. J. Raju, and G. Pillai, “Low Temperature and DC Bias Dependence Study of Barium Strontium Titanate Based High Overtone Bulk Acoustic Resonator (HBAR)” 2022 30th International Conference on Electrical Engineering (ICEE), Bengaluru, India, December 2022.

27.  C.-Y. Chang, G. Pillai, and S.-S. Li, "Phase noise optimization of piezoelectric bulk mode mems oscillators based on phase feedback in secondary loop,” 2022 IEEE, 35th International Conference on Micro Electro Mechanical Systems Conference (MEMS), 2022, pp. 212-215.

28.  C.-Y. Chang, G. Pillai, and S.-S. Li, "A Semi-Analytical Modeling of Coupled Piezoelectric Resonators Based on Support Transducer Topology,” Tech. Digest, 2022 Hilton Head MEMS Conf., 2022.

Before joining IISc

29.  C.-H. Weng, G. Pillai, and S.-S. Li, "A mass sensor based on an aluminum nitride MEMS oscillator for gas sensing applications,” Tech. Dig., 21st Int. Conf. on Solid-State Sensors & Actuators (Transducers’21), Virtual Conference, June 20-25, 2021, pp. 1287-1290

30.  C. -H. Weng, C.-Y. Wu, G. Pillai, and S. -S. Li, "A Miniaturized PM2.5 Sensor Module Based on a Thin-Film Piezoelectric-on-Silicon MEMS Oscillator,” 2021 IEEE International Symposium on Applications of Ferroelectrics (ISAF), 2021, pp. 1-4.

31.  N. M. Nguyen, C.-Y. Chang, G. Pillai, and S.-S. Li, "Design of piezoelectric MEMS bulk acoustic wave mode-matched gyroscopes based on support transducer,” (oral presentation) in the 34th IEEE Int. Micro Electro Mechanical Systems Conf. (MEMS’21), Jan. 25-29, 2021.

32.  H. -T. Jen, G. Pillai, S. L. Liu, and S. S. Li, "Low phase noise wine-glass oscillator realized using enhanced support transducer design,” Proceedings, the 2020 Joint Conference of the IEEE International Frequency Control Symposium and International Symposium on Applications of Ferroelectrics (IFCS-ISAF), Keystone, CO, USA, Jul. 19-23, 2020, pp. 1-3. (STUDENT PAPER FINALIST)

33.  K. Bhosale, G. Pillai, and S. -S. Li, "Nonlinearity driven higher order harmonics in CMOS-MEMS resonators,” Proceedings, Joint Conference of the IEEE International Frequency Control Symposium and International Symposium on Applications of Ferroelectrics (IFCS-ISAF), Keystone, CO, USA, Jul. 19-23, 2020, pp. 1-3.

34.  C.-Y. Liu, G. Pillai, and S.-S. Li, "Exploring the parametric energy transfer in a multi-mode piezoelectric resonator with nonlinear harmonics,” to be presented in 33rd IEEE Int. Micro Electro Mechanical Systems Conf. (MEMS’20), Vancouver, Canada, Jan. 18-22, 2020. (STUDENT PAPER FINALIST).

35.  G. Pillai and S.-S. Li, “Frequency Matched Bulk Mode Piezoelectric Transducer to Excite High-Q Phononic Crystal Lattice”, International Conference on Smart Sensors 2020, Taiwan [Best Oral Presentation Award].#

36.  G. Pillai, M.-F. Lai, and S.-S. Li, "A fully differential thin film piezo on silicon flexural mode ring resonator with exceptional quality factor,” Proceedings, 20th Int. Conf. on Solid-State Sensors & Actuators (Transducers’19), Berlin, Germany, June 23-27, 2019, pp. 889-892.

37.  G. Pillai, C.-Y. Chen, and S.-S. Li, "Support transducer enabled single-resonator channel-select filters,” Proceedings, 2019 Joint Conference of the IEEE International Frequency Control Symposium & European Frequency and Time Forum, Orlando, Florida, April 14-18, 2019, pp. 1-2.

38.  G. Pillai and S.-S. Li, “Novel Thin Film Piezoelectric-on-Substrate MEMS Devices for RF Application”, NAMIS Workshop, Organized by VTT Oulu and CNRS France, IIT Bombay, India, November 2019. #

39.  G. Pillai, C.Y.Chen, and S.-S. Li, " Support Transducer Enabled Single-Resonator Channel-Select Filters,” International Conference on Smart Sensors (June 2019, Taiwan. [Honorary Oral Presentation Award] #

40.  G. Pillai, A. A. Zope, and S.-S. Li, "Piezoelectrically transduced Lamé-mode resonators and oscillators,” Proceedings, 2018 IEEE Frequency Control Symposium, Olympic Valley, CA, May 21-24, 2018, pp. 324-325.

41.  G. Pillai, A. A. Zope, and S.-S. Li, "A novel transducer design to enable high-performance piezoelectric MEMS resonators and oscillators,” Proceedings, 31st IEEE Int. Micro Electro Mechanical Systems Conf. (MEMS’18), Belfast, Northern Ireland, Jan. 21-25, 2018, pp. 166-169.

42.  G. Fang, G. Pillai, M.-H. Li, C.-Y. Liu, and S.-S. Li, "A VHF temperature compensated lithium niobate on-oxide resonator with Q > 3900 for low phase noise oscillators,” Proceedings, 31st IEEE Int. Micro Electro Mechanical Systems Conf. (MEMS’18), Belfast, Northern Ireland, Jan. 21-25, 2018, pp. 723-726.

43.  T.-Y. Liu, C.-A. Sung, C.-H. Weng, C.-C. Chu, A. A. Zope, G. Pillai, and S.-S. Li, "Gated CMOS-MEMS thermal-piezoresistive oscillator-based PM2.5 sensor with enhanced particle collection efficiency,” Proceedings, 31st IEEE Int. Micro Electro Mechanical Systems Conf. (MEMS’18), Belfast, Northern Ireland, Jan. 21-25, 2018, pp. 75-78.

44.  G. Pillai and S.-S. Li, “Support transducer design to enable piezoelectrically transduced Lamé-mode resonator and oscillator, “International Conference on Smart Sensors (June 2018), Taiwan. #

45.  G. Pillai, A. A. Zope, J. M.-L. Tsai, and S.-S. Li, "An apodized 3-GHz thin film piezoelectric on substrate FBAR,” Proceedings, 2017 European Frequency and Time Forum & International Frequency Control Symposium (EFTF-IFCS’17), Besançon, France, July 10-13, 2017, pp. 551-553.

46.  C. Y. Chen, M. H. Li, G. Pillai, J. M. L. Tsai and S. S. Li, "An innovative piezo-MEMS channel-select filter design based on non-monotonic coupled modes,” Proceedings, 30th IEEE Int. Micro Electro Mechanical Systems Conf. (MEMS’17), Las Vegas, NV, Jan. 22-26, 2017, pp. 950-953.

47.  G. Pillai, A.-A. Zope, J. M.-L. Tsai, and S.-S. Li, "3-GHz BAW composite resonators integrated with CMOS in a single-chip configuration,” Proceedings, 2016 IEEE Int. Frequency Control Symp., New Orleans, LA, May 9-12, 2016.

48.  G. Pillai, W.-S. Tan, C.-C. Chen, and S.-S. Li, "Modeling of zero TCF and maximum bandwidth orientation for lithium tantalate RF MEMS resonators,” Proceedings, 11th Annual IEEE International Conference on Nano/Micro Engineered and Molecular Systems (IEEE-NEMS 2016), Japan, 17-20 April.

49.  W.-S. Tan, W. G. Fang, G. Pillai, C.-C. Chen, C.-Y. Chen, C.-H. Chin, and S.-S. Li, "Fabrication and characterization of lithium-niobate thin film MEMS piezoelectric resonators,” Proceedings, 11th Annual IEEE International Conference on Nano/Micro Engineered and Molecular Systems (IEEE-NEMS 2016), Matsushima Bay and Sendai MEMS City, Japan, 17-20 April.

#Presentations without proceedings.