Innovative Multi-Band Antenna Designs for Internet of Sea Applications
Monitoring the ocean environment is essential for understanding climate change, protecting marine biodiversity, and enabling sustainable exploitation of marine resources. Human activities such as oil spills and overfishing have significantly disrupted oceanic ecosystems. As a result, there is increasing interest in monitoring marine environments and tracking the health of aquatic species to identify signs of ecological stress. However, acquisition of data from oceans has been a challenging and expensive task. Marine environment lacks adequate communication infrastructures, and traditional solutions such as monitoring ships and underwater cable networks remain prohibitively expensive and logistically complex. These limitations underscore the need for low-cost, scalable, and autonomous ocean monitoring systems.
Overview
The Internet of sea networks provides a promising solution. These systems typically consist of low-power sensor nodes—often embedded in animal tags—and surface-level communication relays such as floating buoys. While few marine IoT systems have been proposed in literature, their antenna designs are often repurposed from terrestrial use and fail to meet the stringent demands of the ocean environment. The frequency bands, size constraints, and seawater isolation call for novel marine purpose-designed antennas with tailored mechanical and electromagnetic characteristics.
In this dissertation, we first propose a high-performance antenna system designed for oceanic communication buoys. These buoys form a mesh network that relays data across long distances. Operating at both the 900 MHz LoRa and 2.4 GHz BLE ISM bands, the dual-band microstrip antenna array for the horizontal communication exhibits high aperture efficiencies for both bands, with a very low profile. The antenna tower system on top of the buoy has six such dual-band linear arrays to form a hexagonal sectorial array architecture. Besides, to enable global positioning and synchronization, a high-gain circularly polarized GPS antenna array is mounted on top of the hexagonal antenna tower. We design a sequentially rotated right-hand circularly polarized (RHCP) microstrip array that leverages aperture efficiency through a compact, sequentially rotational feeding configuration. This design is optimized to meet the spatial and gain requirements while performing the highest aperture efficiency for similar state-of-the-art designs.
The marine animal sensor tag, as another critical component, supports biological monitoring by recording data directly from aquatic species. Two types of antenna are required: the first is a multiband electrically small (ES) antenna for animals that frequently breathe on sea surface, and the second is a pop-up deployable antenna that can be tightly coiled during underwater operation and later extend above the sea surface upon release.
ES antennas inherently struggle to achieve wideband operation due to fundamental physical limits. Furthermore, the existing literature lacks design methods for multi-band fully ES antennas. We proposed a practical design method for a multi-band ES antenna, which is the first quad-band fully ES antenna, to the best knowledge of us.
In addition, a new deployable antenna is proposed for archive marine animal tags. Specifically, we employ shape memory alloy (SMA) wire that allows the antenna structure to mechanically unfold at room temperature and elevate upon current heating (~70°C). This mechanism not only lifts the antenna above the water surface but also extends antenna size, improving both gain and antenna height. Such adaptive mechanical-electromagnetic co-design remains largely unexplored in prior
Presenters
Brief Biography
Hanguang Liao received the B.E. degree in microelectronics from the University of Electronic Science and Technology of China (UESTC), Chengdu, China in 2019, and the M.S. degree in Electrical and Computer Engineering from the King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia, in 2021, where he is currently pursuing the Ph.D. degree with the IMPACT Laboratory, Electrical and Computer Engineering Program.
Hanguang Liao was the First Place Winner of the 2022 IEEE AP-S Student Design Contest. He was also the Second Place Winner of the 2024 IEEE IMS Student Design Contest.
