Abstract: The rapid evolution of wireless technologies has been driven by an ever-increasing demand for seamless, high-data-rate connectivity—anywhere and anytime. While advances in low-power electronics and miniaturized systems have enabled this transformation, antennas remain a critical bottleneck, particularly for emerging mobile and robotic platforms where size, efficiency, bandwidth, and polarization control are tightly constrained. Looking ahead, the proliferation of autonomous and networked robotic systems, which operate in coordination with each other, surrounding infrastructure, and human users, places even greater demands on wireless performance. These applications require compact, low-profile antennas that maintain high efficiency while supporting polarization and radiation pattern agility.

For many terrestrial and near-Earth communication scenarios, vertically polarized radiation is preferred due to its lower propagation path loss compared to other polarization states. However, conventional vertically polarized antennas, such as dipoles and monopoles, are inherently bulky and non-conformal, making them unsuitable for integration into compact, mobile platforms. Attempts to reduce antenna height using traditional techniques typically result in severe degradation in radiation efficiency and polarization purity. In this class I introduce a suite of innovative miniaturization strategies for vertically polarized antennas, achieving ultra-low-profile designs with heights as small as λ/300 while preserving high efficiency and polarization integrity. The proposed approaches enable conformal integration into mobile and robotic systems without compromising performance.

To illustrate these concepts in a practical setting, I present an ultra-low-profile substrate integrated millimeter-wave 5G phased array with a height of only 0.1λ for cellphones. The design employs two complementary dual-band antenna elements to realize orthogonal linear polarizations, combining a planar folded dipole for horizontal polarization with a novel hexagonal bridge structure for vertical polarization. A compact 1×4 phased array prototype, implemented using standard multilayer PCB technology, demonstrates broad dual-band operation, wide scan capability, and high gain within a minimal footprint. This example highlights the feasibility of achieving low-cost, low-profile, and high-performance antenna systems for next-generation mobile platforms.

These advances address key limitations in antenna technology and provide a pathway toward high-performance, miniaturized wireless systems for next-generation mobile, robotic, and networked platforms.

Biography: Kamal Sarabandi (S’87-M’90-SM’92-F’00-LF’21) is the Fawwaz T. Ulaby Distinguished University Professor of EECS and the Rufus S. Teesdale Endowed Professor of Engineering at The University of Michigan. His research areas of interest include microwave and millimeter-wave radar remote sensing, Meta-materials, electromagnetic wave propagation, antenna miniaturization, and bio-electromagnetics. Professor Sarabandi has supervised 66 Ph.D. and numerous Masters students and postdoctoral fellows. He has published a text book, many book chapters, more than 360 papers in refereed journals, and more than 780 conference papers. He, together with his students, are recipients of 36 paper awards. Dr. Sarabandi served as a member of NASA Advisory Council for two consecutive terms (2006-2010) and served as the President of the IEEE Geoscience and Remote Sensing Society (2015-2016). He is the past Chair of Commission F of USNC/URSI and serving as member of the AdCom for the IEEE Antennas and Propagation Society. He led numerous NASA projects and served as a member of the Science Team for NASA SMAP mission. He also led a major Center for Microelectronics and Sensors funded by the Army Research Laboratory (2008-2018) and is leading the Center of Excellence in Microwave Sensor Technology. His contributions to the field of electromagnetics have been recognized by many awards including Humboldt Research Award, the IEEE GRSS Distinguished Achievement Award, the IEEE Judith A. Resnik award, the IEEE GRSS Education Award, NASA Group Achievement Award, the 2024 IEEE Electromagnetics Award, and many other awards from the University of Michigan. He is a Life-Fellow of the IEEE, a Fellow of the American Association for the Advancement of Science (AAAS), and a Fellow of the National Academy of Inventors. He received the esteemed recognition of being chosen as one of the inaugural members of the "Legends of Electromagnetics" by the IEEE Antennas and Propagation Society. Professor Sarabandi is a member of the National Academy of Engineering and a 2024 recipient of the prestigious Ellis Island Medal of Honor. The IEEE Board of Directors announced him as the recipient of the 2025 IEEE Dennis J. Picard Medal for Radar Technologies and Applications.