Intelligent Radio and Integrated Systems Laboratory HKUST

Publications

Research conducted in the Intelligent Radio and Integrated Systems (IRIS) Laboratory is disseminated through top-tier international conferences and journals in the field of RF and microwave engineering. These include leading venues such as the IEEE International Microwave Symposium (IMS), the European Microwave Conference (EuMW), and the IEEE Transactions on Microwave Theory and Techniques (T-MTT), among others.

All

2026

Robust Digital Predistortion of Load-Modulated Power Amplifiers Under Varying Signal Conditions
Robust Digital Predistortion of Load-Modulated Power Amplifiers Under Varying Signal Conditions
Mohammad Abdollah Chalaki, Emma Gu, Ahmed Ben Ayed, Patrick Mitran, Slim Boumaiza
IEEE Microwave Magazine  ·  01 Jan 2026  ·  doi:10.1109/MMM.2026.3652159

2025

Millimeter-Wave Wideband Active Load Pull System Using Vector Network Analyzer Frequency Extenders
Millimeter-Wave Wideband Active Load—Pull System Using Vector Network Analyzer Frequency Extenders
Ahmed Ben Ayed, Slim Boumaiza
IEEE Microwave and Wireless Technology Letters  ·  01 Jun 2025  ·  doi:10.1109/LMWT.2025.3564839
Frequency-Stitching-Based Ultrawideband Signal Generation for 6G Component System Testing: Achieving 12-GHz Instantaneous Bandwidth and 96-Gbps Data Rate at D Band
Frequency-Stitching-Based Ultrawideband Signal Generation for 6G Component/System Testing: Achieving 12-GHz Instantaneous Bandwidth and 96-Gbps Data Rate at D Band
Zi Jun Su, Ahmed Ben Ayed, Nizar Messaoudi, Patrick Mitran, Slim Boumaiza
IEEE Transactions on Microwave Theory and Techniques  ·  01 May 2025  ·  doi:10.1109/TMTT.2024.3487823
Comparative Study of Two Architectures Suitable for the Generation of Wideband Signals at Sub-THz
Comparative Study of Two Architectures Suitable for the Generation of Wideband Signals at Sub-THz
Zi Jun Su, Ahmed Ben Ayed, Patrick Mitran, Slim Boumaiza
2025 104th ARFTG Microwave Measurement Conference (ARFTG)  ·  19 Jan 2025  ·  doi:10.1109/arftg63706.2025.10989806
A Piecewise Interpolation Based Digital Predistortion of Power Amplifiers Across Wide Power Ranges
A Piecewise Interpolation Based Digital Predistortion of Power Amplifiers Across Wide Power Ranges
Nizar Messaoudi, Ahmed Ben Ayed, Slim Boumaiza
2025 104th ARFTG Microwave Measurement Conference (ARFTG)  ·  19 Jan 2025  ·  doi:10.1109/arftg63706.2025.10989809
Recent Advances in Linearization Techniques for Frequency Multiplier-Based Transmitters Driven With Vector-Modulated Signals
Recent Advances in Linearization Techniques for Frequency Multiplier-Based Transmitters Driven With Vector-Modulated Signals
Ahmed Ben Ayed, Patrick Mitran, Slim Boumaiza
IEEE Microwave Magazine  ·  01 Jan 2025  ·  doi:10.1109/MMM.2024.3474388

2024

Digital Predistortion of Frequency Multiplier-Based Vector Signal Sources With Constrained Transmitter and Observation Receiver Bandwidth
Digital Predistortion of Frequency Multiplier-Based Vector Signal Sources With Constrained Transmitter and Observation Receiver Bandwidth
Ahmed Ben Ayed, Ifrah Jaffri, Ali M. Darwish, Patrick Mitran, Slim Boumaiza
IEEE Transactions on Microwave Theory and Techniques  ·  01 Nov 2024  ·  doi:10.1109/tmtt.2024.3400688
Wideband Vector Signal Generation Using Multiple Narrowband Phase-Coherent Synchronous Signal Channels
Wideband Vector Signal Generation Using Multiple Narrowband Phase-Coherent Synchronous Signal Channels
Zi Jun Su, Ahmed Ben Ayed, Slim Boumaiza
2024 103rd ARFTG Microwave Measurement Conference (ARFTG)  ·  21 Jun 2024  ·  doi:10.1109/arftg61196.2024.10660844
Linearizability Assessment of a 3.5 GHz 16-Chain Fully Digital MIMO Transmitter Under Wideband Modulated Signals
Linearizability Assessment of a 3.5 GHz 16-Chain Fully Digital MIMO Transmitter Under Wideband Modulated Signals
Hoda Barkhordar-Pour, Jin Gyu Lim, Ahmed Ben Ayed, Patrick Mitran, Slim Boumaiza
2024 103rd ARFTG Microwave Measurement Conference (ARFTG)  ·  21 Jun 2024  ·  doi:10.1109/arftg61196.2024.10660695
Comparison of Signal Generation Approaches for Component Testing at D-Band
Comparison of Signal Generation Approaches for Component Testing at D-Band
Zi Jun Su, Nizar Messaoudi, Ahmed Ben Ayed, Jean-Pierre Teyssier, Slim Boumaiza
2024 103rd ARFTG Microwave Measurement Conference (ARFTG)  ·  21 Jun 2024  ·  doi:10.1109/arftg61196.2024.10660848
UAV-Based Relays Using Active Phased Arrays for Non-Line-of-Sight Millimeter-Wave Communications: Real-Time Field Testing
UAV-Based Relays Using Active Phased Arrays for Non-Line-of-Sight Millimeter-Wave Communications: Real-Time Field Testing
Xiaofei Zhang, Nita Esfarayeni, Ahmed Ben Ayed, Mohammad Abdollah Chalaki, Pouya Namaki, Huixin Jin, Slim Boumaiza
2024 IEEE/MTT-S International Microwave Symposium - IMS 2024  ·  16 Jun 2024  ·  doi:10.1109/ims40175.2024.10600265
Millimeter-Wave Device Characterization Under Wideband Modulated Signals Using Vector Network Analyzer Frequency Extenders
Millimeter-Wave Device Characterization Under Wideband Modulated Signals Using Vector Network Analyzer Frequency Extenders
Ahmed Ben Ayed, Patrick Mitran, Slim Boumaiza
IEEE Microwave and Wireless Technology Letters  ·  01 Jun 2024  ·  doi:10.1109/LMWT.2024.3383335
Active Calibration Approach Addressing Antenna Mutual Coupling and Power Amplifier Output Mismatch in Fully Digital MIMO Transmitters
Active Calibration Approach Addressing Antenna Mutual Coupling and Power Amplifier Output Mismatch in Fully Digital MIMO Transmitters
Hoda Barkhordar-Pour, Jin Gyu Lim, Ahmed Ben Ayed, Patrick Mitran, Slim Boumaiza
IEEE Microwave and Wireless Technology Letters  ·  01 Jun 2024  ·  doi:10.1109/LMWT.2024.3382595

2023

A V-Band 16 Efficiency Frequency Doubler-Based RF Beamforming Front-End Module for Vector Modulated Signal Transmission
A V-Band 16% Efficiency Frequency Doubler-Based RF Beamforming Front-End Module for Vector Modulated Signal Transmission
Mahitab Eladwy, Ahmed Ben Ayed, Ali M. Darwish, Slim Boumaiza
2023 53rd European Microwave Conference (EuMC)  ·  19 Sep 2023  ·  doi:10.23919/eumc58039.2023.10290530
Novel Algorithm to Synthesize the Tapering Profile for Enhanced Linearization of RF Beamforming Arrays Over a Wide Steering Range
Novel Algorithm to Synthesize the Tapering Profile for Enhanced Linearization of RF Beamforming Arrays Over a Wide Steering Range
Ahmed Ben Ayed, Patrick Mitran, Slim Boumaiza
IEEE Transactions on Microwave Theory and Techniques  ·  01 Aug 2023  ·  doi:10.1109/TMTT.2023.3248151
VNA-Based Characterization of Frequency Multipliers Phase-Distortions Under Continuous-Wave and Modulated Signal Excitation
VNA-Based Characterization of Frequency Multipliers Phase-Distortions Under Continuous-Wave and Modulated Signal Excitation
Mahitab Eladwy, Ahmed Ben Ayed, Slim Boumaiza
2023 101st ARFTG Microwave Measurement Conference (ARFTG)  ·  16 Jun 2023  ·  doi:10.1109/arftg57476.2023.10278907
New Digital Predistortion Training Method with Cross-Polarization Channel De-Embedding for Linearizing Dual-Polarized Arrays using Far-Field Observation Receiver
New Digital Predistortion Training Method with Cross-Polarization Channel De-Embedding for Linearizing Dual-Polarized Arrays using Far-Field Observation Receiver
Nizar Messaoudi, Ahmed Ben Ayed, Ziran He, Bernard Tung, Patrick Mitran, Slim Boumaiza
2023 IEEE/MTT-S International Microwave Symposium - IMS 2023  ·  11 Jun 2023  ·  doi:10.1109/ims37964.2023.10187920
Embedded Near-Field Probing Antenna for Enhancing the Performance of 37 41-GHz Linear and Dual-Polarized Phased Antenna Arrays
Embedded Near-Field Probing Antenna for Enhancing the Performance of 37–41-GHz Linear and Dual-Polarized Phased Antenna Arrays
Huixin Jin, Ahmed Ben Ayed, Ziran He, Bernard Tung, Slim Boumaiza
IEEE Microwave and Wireless Technology Letters  ·  01 Jun 2023  ·  doi:10.1109/LMWT.2023.3268570
Array Calibration and Digital Predistortion Training Using Embedded Near-Field Feedback Probes and Orthogonal Coding for Enhancing the Performance of Millimeter-Wave Beamforming Arrays
Array Calibration and Digital Predistortion Training Using Embedded Near-Field Feedback Probes and Orthogonal Coding for Enhancing the Performance of Millimeter-Wave Beamforming Arrays
Ahmed Ben Ayed, Huixin Jin, Bernard Tung, Patrick Mitran, Slim Boumaiza
IEEE Microwave and Wireless Technology Letters  ·  01 Jun 2023  ·  doi:10.1109/LMWT.2023.3264877
On the Viability of Using a Subset of Transmitter- Observation Receivers for Training a Common DPD in Fully Digital MIMO Transmitters
On the Viability of Using a Subset of Transmitter- Observation Receivers for Training a Common DPD in Fully Digital MIMO Transmitters
Jin Gyu Lim, Hoda Barkhordar-Pour, Ahmed Ben Ayed, Patrick Mitran, Slim Boumaiza
IEEE Microwave and Wireless Technology Letters  ·  01 Jun 2023  ·  doi:10.1109/LMWT.2023.3268550
VNA-Based Testbed for Accurate Linearizability Testing of RF Beamforming Arrays Under Modulated Signals
VNA-Based Testbed for Accurate Linearizability Testing of RF Beamforming Arrays Under Modulated Signals
Nizar Messaoudi, Ahmed Ben Ayed, Joel Dunsmore, Slim Boumaiza
2023 100th ARFTG Microwave Measurement Conference (ARFTG)  ·  22 Jan 2023  ·  doi:10.1109/arftg56062.2023.10148892

2022

Analysis and Linearization of Frequency-Multiplier-Based RF Beamforming Transmitters Over a Wide Steering Range
Analysis and Linearization of Frequency-Multiplier-Based RF Beamforming Transmitters Over a Wide Steering Range
Ahmed Ben Ayed, Ifrah Jaffri, Mahitab ElAdwy, Ali M. Darwish, Patrick Mitran, Slim Boumaiza
IEEE Transactions on Microwave Theory and Techniques  ·  01 Aug 2022  ·  doi:10.1109/tmtt.2022.3186340
Digital Predistortion of Millimeter-Wave Arrays Using Near-Field Based Transmitter Observation Receivers
Digital Predistortion of Millimeter-Wave Arrays Using Near-Field Based Transmitter Observation Receivers
Ahmed Ben Ayed, Yushi Cao, Patrick Mitran, Slim Boumaiza
IEEE Transactions on Microwave Theory and Techniques  ·  01 Jul 2022  ·  doi:10.1109/tmtt.2022.3174857
VNA-Based Testbed for Accurate Linearizability Testing of Power Amplifiers Under Modulated Signals
VNA-Based Testbed for Accurate Linearizability Testing of Power Amplifiers Under Modulated Signals
Nizar Messaoudi, Ahmed Ben Ayed, Jean-Pierre Teyssier, Slim Boumaiza
2022 99th ARFTG Microwave Measurement Conference (ARFTG)  ·  24 Jun 2022  ·  doi:10.1109/arftg54656.2022.9896586
Dual-Input Digital Predistortion of Millimeter-Wave RF Beamforming Arrays Driven by Two Non-Contiguous Intra-band Signals
Dual-Input Digital Predistortion of Millimeter-Wave RF Beamforming Arrays Driven by Two Non-Contiguous Intra-band Signals
Ahmed Ben Ayed, Yushi Cao, Patrick Mitran, Slim Boumaiza
2022 IEEE/MTT-S International Microwave Symposium - IMS 2022  ·  19 Jun 2022  ·  doi:10.1109/ims37962.2022.9865460
Proof-of-Concept of Millimeter-Wave RF Beamforming Transmitter Architecture Employing Frequency-Multiplier-Based Up-Converters
Proof-of-Concept of Millimeter-Wave RF Beamforming Transmitter Architecture Employing Frequency-Multiplier-Based Up-Converters
Ahmed Ben Ayed, Ifrah Jaffri, Ali M. Darwish, Patrick Mitran, Slim Boumaiza
IEEE Microwave and Wireless Components Letters  ·  01 Jun 2022  ·  doi:10.1109/lmwc.2022.3162992

2021

A 60 GHz CMOS-SOI Stacked Push-Push Frequency Doubler with 12 dBm Output Power and 20 Efficiency
A 60 GHz CMOS-SOI Stacked Push-Push Frequency Doubler with 12 dBm Output Power and 20% Efficiency
Mahitab Eladwy, Jingjing Xia, Ahmed Ben Ayed, Slim Boumaiza
2021 IEEE MTT-S International Microwave Symposium (IMS)  ·  07 Jun 2021  ·  doi:10.1109/ims19712.2021.9574811
Uniformly Distributed Near-Field Probing Array for Enhancing the Performance of 5G Millimeter-Wave Beamforming Transmitters
Uniformly Distributed Near-Field Probing Array for Enhancing the Performance of 5G Millimeter-Wave Beamforming Transmitters
Yushi Cao, Ahmed Ben Ayed, Jingjing Xia, Slim Boumaiza
IEEE Microwave and Wireless Components Letters  ·  01 Jun 2021  ·  doi:10.1109/lmwc.2021.3067168
Digital Predistortion of Millimeter-Wave Hybrid Beamforming Transmitters Using Observation Receivers With Low-Bit Resolution Analog-to-Digital Converter
Digital Predistortion of Millimeter-Wave Hybrid Beamforming Transmitters Using Observation Receivers With Low-Bit Resolution Analog-to-Digital Converter
Ahmed Ben Ayed, Eric Ng, Patrick Mitran, Slim Boumaiza
IEEE Access  ·  01 Jan 2021  ·  doi:10.1109/access.2021.3096978

2020

Novel Baseband Equivalent Model for Digital Predistortion of Wideband Frequency-Multiplier-Based Millimeter Wave Sources
Novel Baseband Equivalent Model for Digital Predistortion of Wideband Frequency-Multiplier-Based Millimeter Wave Sources
Ifrah Jaffri, Ahmed Ben Ayed, Ali M. Darwish, Patrick Mitran, Slim Boumaiza
IEEE Transactions on Microwave Theory and Techniques  ·  01 Sep 2020  ·  doi:10.1109/tmtt.2020.2992914
On the Effectiveness of Near-Field Feedback for Digital Pre-Distortion of Millimeter-Wave RF Beamforming Arrays
On the Effectiveness of Near-Field Feedback for Digital Pre-Distortion of Millimeter-Wave RF Beamforming Arrays
Ahmed Ben Ayed, Giovanni Scarlato, Patrick Mitran, Slim Boumaiza
2020 IEEE/MTT-S International Microwave Symposium (IMS)  ·  01 Aug 2020  ·  doi:10.1109/ims30576.2020.9223791
High-Frequency Vector-Modulated Signal Generation Using Frequency-Multiplier-Based RF Beamforming Architecture
High-Frequency Vector-Modulated Signal Generation Using Frequency-Multiplier-Based RF Beamforming Architecture
Ifrah Jaffri, Ahmed Ben Ayed, Ali M. Darwish, Slim Boumaiza
2020 IEEE/MTT-S International Microwave Symposium (IMS)  ·  01 Aug 2020  ·  doi:10.1109/ims30576.2020.9223961
Millimeter Wave SOI-CMOS Power Amplifier With Enhanced AM-PM Characteristic
Millimeter Wave SOI-CMOS Power Amplifier With Enhanced AM-PM Characteristic
Jingjing Xia, Xiaohu Fang, Ahmed Ben Ayed, Slim Boumaiza
IEEE Access  ·  01 Jan 2020  ·  doi:10.1109/access.2020.2964670

2019

Digital Predistortion of Millimeter-Wave RF Beamforming Arrays Using Low Number of Steering Angle-Dependent Coefficient Sets
Digital Predistortion of Millimeter-Wave RF Beamforming Arrays Using Low Number of Steering Angle-Dependent Coefficient Sets
Eric Ng, Yehia Beltagy, Giovanni Scarlato, Ahmed Ben Ayed, Patrick Mitran, Slim Boumaiza
IEEE Transactions on Microwave Theory and Techniques  ·  01 Nov 2019  ·  doi:10.1109/tmtt.2019.2924893
Single-Input Single-Output Digital Predistortion of Multi-user RF Beamforming Arrays
Single-Input Single-Output Digital Predistortion of Multi-user RF Beamforming Arrays
Eric Ng, Ahmed Ben Ayed, Patrick Mitran, Slim Boumaiza
2019 IEEE MTT-S International Microwave Symposium (IMS)  ·  01 Jun 2019  ·  doi:10.1109/mwsym.2019.8700932