Zakir Ullah is a Doctoral Researcher at the Centre for Wireless Communications–Radio Engineering, University of Oulu, Finland. His research interests include RF and antenna engineering, reconfigurable intelligent surfaces, metasurfaces, space-time modulation, on-surface modulation, and emerging wireless technologies for 5G and 6G communications. His current work focuses on the design, simulation, and experimental characterization of metasurface-based wireless systems and direct modulation techniques. He received his Master’s degree in Information and Communication Engineering from Harbin Institute of Technology, China, where he worked on low-profile Fabry–Perot cavity antennas for Wi-Fi applications, and his Bachelor’s degree in Electronics Engineering from Islamia College Peshawar, Pakistan, where he graduated as the top student of his batch and received a Gold Medal. His research experience spans antenna and metasurface design, RF/microwave engineering, wireless communications, IoT, power converters and electromagnetic simulation and measurement.