Exploring tunable materials for reconfigurable antenna technology

The combination of tunable materials in reconfigurable antennas has been essential since the advent of microwave, mmWave, and THz technologies. These materials, including phase shifters, resonators, filters, and antennas; enable critical functions such as RF signal filtering, beamforming, and beam steering, which are essential for modern wireless communication systems. The expansion of wireless networks, especially with 5G, satellite, and advanced radar systems, demands enhanced adaptability in frequency, radiation patterns, and polarization, ushering in a new era of flexible wireless technology. As operational frequencies extend into the mmWave range and beyond, traditional tunable RF components like MEMS switches, PIN diodes, ferrites, and ferroelectric films encounter challenges such as performance degradation, fabrication complexity, and high costs. Liquid crystals (LCs) have emerged as a promising alternative, offering continuous bias-controlled tuning of dielectric constants, low losses, minimal dispersion, and cost-effective fabrication. This presentation delivers a comprehensive review of tunable materials, focusing on LCs and their key properties, characterization methods, and performance metrics at frequencies above 10 GHz. Material selection guidelines for various RF/microwave/mmWave applications will be discussed, alongside insights into common experimental discrepancies and their origins. An innovative reconfigurable microstrip antenna utilizing LC cavities is introduced, enabling electronic switching between linear and dual-sense circular polarization. The design incorporates a square patch with integrated LC regions and parasitic biasing patches to achieve polarization reconfiguration seamlessly.

The talk highlights recent advancements in tunable material-enabled antenna systems, emphasizing frequency agility and beam steering via bias voltage control, with examples including leaky-wave, array, and circularly polarized antennas—showcasing their potential for energy-efficient, adaptable wireless communications.

Dr. Nasimuddin received his M.Tech. and Ph.D. degrees from the University of Delhi. He was a SRF at University of Delhi (1999-2003) and subsequently held the position of ARC Fellow at Macquarie University (2004-2006). He is currently a Principal Scientist at the Institute for Infocomm Research, A*STAR, Singapore. He is a prolific contributor to the field, with over 260 research publications, 3 edited books, 4 granted and 3 filed patents. His outstanding work has earned him recognition as one of the top 2% of scientists worldwide in 2023, 2024, and 2025. He is a Senior Member of the IEEE and its APS/MTTS, as well as a Life Fellow of WAMS Society. His accolades include the URSI Young Scientist Award (2005) and multiple IEEE AP-T/AWPL Exceptional Performance Reviewer Awards. He serves as an Associate Editor for the IEEE OJAP, Editor-in-Chief of WCL. He served as Chair of IEEE Singapore MTT/AP-Joint Chapter (2021-2022).