# A High-Performance Thin-Film Sensor in 6G for Remote Sensing of the Sea Surface
## 1 Introduction  
Marine pollution is the result of human activities that alter the natural state of the ocean, leading to detrimental effects on marine ecosystems [1; 2; 3]. Pollution caused by harmful substances entering the marine environment can damage biological resources, endanger human health, prevent fishing and other human activities at sea, and damage the quality of seawater and the overall environment. Marine ecosystems are the most important in the world and affect the stability and security of the global ecosystem. Additionally, the survival of human beings and their economic, political, cultural, and social development are closely related to the ocean. Seawater testing is one of the most important ways to determine whether the ecology of the ocean is polluted [4; 5]. \"Oil in water\" is the oil in the water body, which is mainly derived from industrial wastewater, domestic sewage discharge, animal decomposition, and other sources. The harm caused by oil is clear; first of all, it can consume the oxygen in the water and deteriorate its quality. Moreover, some oil becomes dispersed in the water, is partly adsorbed in suspended particles, or is in a state of emulsion in the water column, being partly dissolved in water. The oil in the water that is in the process of decomposition and oxidation by microorganisms consumes oxygen, so the deterioration in the water quality, in conjunction with oil floating on the surface of the water column,affects the gas exchange of the air-water column interface. The formation of an oil film means that the water column cannot be quickly replenished from the CO\({}_{2}\) in the air, thus promoting the increased deterioration of the water quality. Second, it poisons marine life and damages fishery production. Therefore, the accurate measurement of oil composition and content in water, its detection, and the monitoring of the phenomenon of oil in water is necessary to protect the natural environment and reduce the impact of pollution on human production and life. Common methods currently used in marine oil pollutant detection mainly include the weight method, the turbidity method, chromatography, fluorescence photometry, infrared spectrophotometry, ultraviolet spectrophotometry, and other related methods of coupled technology. However, considering the use environment, detection accuracy, and detection rate, it is extremely important to research for rapid, unrestricted conditions and accurate marine water information detection technology [6; 7; 8]. Remote sensing technology is a highly effective method for maximizing the utilization of existing data and information resources. It serves as a key technology and an important tool for achieving the sustainable development of marine resources and the environment. This technology plays a crucial role in various areas such as global change, resource surveys, and environmental monitoring and prediction, which cannot be replicated by other technologies [7; 8; 9]. At the same time, the process of maintaining the sustainable development of marine resources and the environment will promote the development of information science and technology, space science and technology, environmental science and technology, and earth science [9; 10]. Compared with conventional marine survey methods, marine remote sensing technology has obvious advantages, such as not being limited by geographical location, weather, and human conditions; it can cover large areas and obtain more marine information. In attempting to achieve an accurate understanding of ocean information, ocean remote sensing encounters the following challenges: the ocean reflection signal is weak and the spectral difference between phenomena is small, and ocean remote sensing requires sensors with high temporal resolutions and high spectral resolutions.