A Compact Monopole Antenna for Underwater Acoustic Monitoring Beacons

Area of Science:

• Environmental Science
• Electrical Engineering
• Antenna Theory

Background:

• Protected wetlands are vital habitats for endangered species.
• Illegal human activities, such as motor boat incursions, threaten these ecosystems.
• Effective monitoring systems are crucial for wetland conservation.

Purpose of the Study:

• To design and validate a network of floating beacons for underwater acoustic monitoring of wetlands.
• To develop compact monopole antennas for these beacons using a genetic algorithm approach.
• To address challenges posed by small ground planes and common mode currents in antenna design.

Main Methods:

• A genetic algorithm was employed to design compact monopole antennas with size constraints.
• A distance averaging method was used to investigate common mode current effects.
• A single-antenna method was utilized for antenna characterization.
• A network of LoRa-enabled floating beacons operating at 433 MHz was deployed for monitoring.

Main Results:

• Compact monopole antennas suitable for floating beacons were successfully designed.
• The developed monitoring system effectively detected and recorded motor boat incursions in a lake.
• Experimental validation confirmed the system's capability for real-world wetland monitoring.

Conclusions:

• The developed acoustic monitoring system with genetically optimized compact antennas is effective for detecting unauthorized motor boat activity in protected wetlands.
• The study demonstrates a viable technological solution for enhancing the security and conservation of sensitive aquatic environments.
• Antenna design optimization is critical for the performance of compact monitoring devices in challenging environments.