Fifth generation (5G) and beyond wireless networks use high-band frequencies to offer ultra-fast data rates with minimal latency. However, operating in high-band frequencies introduces significant challenges like increased path loss and reduced signal penetration. Reconfigurable reflectarrays (RAs) are often deployed as a low-cost and highly efficient solution due to their ability to dynamically steer beams using phase-tunable unit cells. Traditional RA designs rely on solid-state components such as PIN diodes, MEMS switches, or tunable materials to induce phase tuning. These approaches often introduce fabrication complexity, high power consumption, and limited scalability. This thesis explores a novel class of reconfigurable RA designs that utilize a unique material called liquid metal (LM) Galinstan to induce phase reconfiguration instead. The work focuses on Galinstan’s ability to be deformed and moved to create mechanically and electrically reconfigurable delay line elements for RA use. This is enabled by microfluidic techniques like continuous electrowetting (CEW) and electrocapillary actuation (ECA). Several unit cell designs were modeled using Ansys HFSS, fabricated using soft lithography and laser micromachining, and tested in custom 3.5-GHz and 28-GHz antenna testbeds. Measured results demonstrate an ability to perform anomalous beam steering within an accuracy of 4° for all fabricated prototypes. In addition to the hardware innovations, this work developed a suite of computational tools to assist in the automation of reflectarray design tasks, including a phase schema generator and a radiation pattern solver. The presented liquid-metal RA paradigm offers a scalable, low-power alternative to conventional RA technologies.

Matthew T. Kouchi is an M.S. candidate in Electrical and Computer Engineering at the University of Hawaii at Manoa. He received a B.S. in Electrical Engineering from the University of Hawaii at Manoa in 2023. His current research focuses on liquid metal and its application in reconfigurable reflective surfaces.