Research

Our research centers on advancing radio frequency (RF)/ millimeter-wave (MMW) and Terahertz (THz) integrated circuits and systems for next-generation communications and sensing, spanning from IoT to high-frequency 5G/6G applications, and high-speed connectivity with advanced packaging. These efforts are focused on enabling a future of seamless, intelligent, high-speed connectivity that can reliably support over one trillion sensors and mobile devices, operating efficiently under any conditions and at any time. Additionally, these advancements aim to achieve low-latency and efficient communication through heterogeneous integration, whether connecting Silicon chips to III-V compound power or low-noise amplifiers or integrating EIC transmitters and receivers with optical processors to meet the next generation’s massive data processing needs in data centers. The core directions of our work are:

Thrust 1: Massive/Scalable System: Designing intelligent, reconfigurable, multifunctional/multiband systems for efficient, low-power solutions in distributed wireless networks.

Thrust 2: Antenna and RF -to-Compute Connectivity (Bits-in-RF):  Integrating backend/baseband (BB) processing within RF integrated circuits (RFICs) and antennas to reduce latency and power consumption (Bringing  Intelligent into RF, Antenna, and Package)

Thrust 3: High-Speed Connectivity, Packaging and Heterogeneous Integration: Developing high-speed interconnects and optimized packaging solutions to improve data rates, reduce losses, and enhance system integration; Incorporating advanced materials into scalable arrays to enhance performance and efficiency.

[1]   S. Z. Aslam and N. Ebrahimi, “A 10 Gb/s, 120 GHz Compact and Energy-Efficient Harmonic-OOK Modulator using 90 nm SiGe BiCMOS,” 2024 IEEE BiCMOS and Compound Semiconductor Integrated Circuits and Technology Symposium (BCICTS), Fort Lauderdale, FL, USA, 2024, pp. 217-220.

[2]  S. Z. Aslam, H. Yan, M. Asghari, H. Li and N. Ebrahimi, “A Compact 130-GHz CMOS OOK-Doubler With Embedded 10-Gb/s Modulator and Integrated Glass Antenna for Scalable Array Systems and Efficient Short-Range Communication,” in IEEE Microwave and Wireless Technology Letters, vol. 34, no. 6, pp. 781-784, June 2024, doi: 10.1109/LMWT.2024.3395645. Selected as Top IMS 2024 Submission, invited to MTTL

[3]  S. Z. Aslam, O. Boomhower, J. Popp and N. Ebrahimi, “Multi Glass-Wafer Stacked Technology for 3D Heterogeneously-Integrated Scalable 6G Arrays,” 2024 IEEE Wireless and Microwave Technology Conference (WAMICON), Clearwater, FL, USA, 2024, pp. 1-4, doi: 10.1109/WAMICON60123.2024.10522862. keywords:

[4]  N. Ebrahimi, “The role of Varactor, the Nonlinear Semiconductor, for Next Generation of Intelligent and Reconfigurable Radio Nodes,” 2024 IEEE 24th Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems (SiRF), San Antonio, TX, USA, 2024, pp. 13-16, doi: 10.1109/SiRF59913.2024.10438640. Invited Talk at Radio Wireless Week 2024.

[5]  P. Pahlavan, S. Z. Aslam and N. Ebrahimi, “A Novel Dual-band and Bidirectional Nonlinear RFID Transponder Circuitry,” 2022 IEEE/MTT-S International Microwave Symposium – IMS 2022, 2022, pp. 44-47.

[6]    N. Ebrahimi, “Compact Heterogeneous Integration for Next Generation High Frequency Scalable Array with Miniaturized and Efficient Power Delivery Network”, accepted to 2022 52nd European Microwave Conference (EuMC), 2022 and currently on arxiv.  arXiv:2111.04567v3

[7]   N. Ebrahimi, K. Sarabandi, J. F. Buckwalter, “A 71-76 / 81-86 GHz, E-band, Phased Array Transceiver Module With Image Selection Weaver Architecture for Low EVM Variation” 2020 IEEE Radio Frequency Integrated Circuits Symposium (RFIC), 2020, pp. 95-98.

[8]  N. Ebrahimi and J. F. Buckwalter, “A High-Fractional-Bandwidth, Millimeter-Wave Bidirectional Image-Selection Architecture with Narrowband LO Tuning Requirements,” in IEEE Journal of Solid-State Circuits, (JSSC), vol. 53, no. 8, pp. 2164-2176, Aug. 2018, (#1 Most Popular Article of JSSC from     Oct. 2018-to-Mar. 2018).

[9]  N. Ebrahimi and J. F. Buckwalter, “A 71–86 GHz Bidirectional Image Selection Transceiver Architecture,” in 2017 IEEE Radio Frequency Integrated Circuits Symposium (RFIC), Honolulu, HI, 2017, pp. 384-387.

[10]  N. Ebrahimi, P. Wu, M. Bagheri and J. F. Buckwalter, “A 71–86-GHz Phased Array Transceiver Using Wideband Injection-Locked Oscillator Phase Shifters,” in IEEE Transactions on Microwave Theory and Techniques (TMTT), vol. 65, no. 2, pp. 346-361, Feb. 2017, (Invited, RFIC Special Issue).

[11] H. Li and N. Ebrahimi, “Invited paper: Dual-Keying Hybrid Modulation for Physical Layer Security in 5G/6G Scalable Array,” 2024 IEEE 67th International Midwest Symposium on Circuits and Systems (MWSCAS), Springfield, MA, USA, 2024, pp. 146-151, doi: 10.1109/MWSCAS60917.2024.10658902. – Selected for  Best Paper Award Competition,  Top 10.

[12]   T. Akyıldız, R. Ku, N. Harder, N. Ebrahimi and H. Mahdavifar, “ML-Aided Collision Recovery for UHF-RFID Systems,” 2022 IEEE International Conference on RFID (RFID), 2022, pp.

[13]   N. Ebrahimi, H. -S. Kim and D. Blaauw, “Physical Layer Secret Key Generation Using Joint Interference and Phase Shift Keying Modulation,” in IEEE Transactions on Microwave Theory and Techniques, vol. 69, no. 5, pp. 2673-2685, May 2021.

[14]  N. Ebrahimi, B. Yektakhah, K. Sarabandi, H. Kim, D. Wentzloff, D. Blaauw, “A Novel Physical Layer Security Technique Using Master-Slave Full Duplex Communication,” in 2019 IEEE MTT-S International Microwave Symposium (IMS), Boston, MA, USA, 2019, pp. 1096-1099.

[15] . N. Ebrahimi, H. Mahdavifar and E. Afshari, “A Novel Approach to Secure Communication in Physical Layer via Coupled Dynamical Systems,” 2018 IEEE Global Communications Conference (GLOBECOM), Abu Dhabi, United Arab Emirates, 2018, pp. 1-7, doi: 10.1109/GLOCOM.2018.8647557.