Marine communication based on a new principle using longitudinal waves generated by polarization in a liquid electrolyte

2023 Fiscal Year Final Research Report

• Project/Area Number: 22K18796
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 21:Electrical and electronic engineering and related fields
• Research Institution: Waseda University
• Principal Investigator: Kawarada Hiroshi 早稲田大学, 理工学術院, 教授 (90161380)
• Project Period (FY): 2022-06-30 – 2024-03-31
• Keywords: 海洋通信 / 塩水通信 / プラズマ・イオン波

Outline of Final Research Achievements

A new method of wireless communication in salt water and seawater pipes was proposed. This method is active as the salt concentration increases. It can transmit data at 1 Mbps or more up to a distance of at least 50 m. It can also be used in tubes and pipes with complex shapes. Since it is based on electrical conduction, it does not pose a problem in opaque environments. However, it requires an environment where the salt water is not in contact with the sea, because the sea is at earth potential and the signal is short-circuited. Applications include small drones for inspecting containers and pipe inner walls in plants where high-salt liquids exist, such as desalination plants and soy sauce factories. The transmission mechanism was clarified from the standpoint of electrical conduction, ion and plasma vibrations, etc. Methods were examined to reduce signal attenuation and increase the transmission distance.

Free Research Field

電気電子工学およびその関連分野

Academic Significance and Societal Importance of the Research Achievements

近年、大規模の淡水化技術、海洋生物の陸上養殖が盛んになり、水と食料の確保の両面から塩水環境での情報収集が重要で、日本でもスマート漁業として進行中である。従来からの超音波技術と開発途上の可視光通信という競合技術があるが、本技術は両技術の間を補完できる。現在、100kHz-10MHz間で1E7m/s-1E8m/sの速度で、50m程度の到達距離である。さらに100m程度まで延伸すれば、海面や海底の反射の影響や濁りの影響もないため、音波よりも情報量が高く、光と異なり濁り影響を受けないため、浅い海での実用化が可能である。また、電解質中の分極した縦波という新たな波動伝搬の開拓として意義がある。