Electromagnetic Waves Under Sea: Bow-Tie Antennas Design for Wi-Fi Underwater Communications

et al. 2016

OCEANS 2016 - Shanghai

In this paper we assess the influence of the conductivity of the medium on the radiation characteristics and input impedance of a loop antenna designed for underwater communications. The initial study is based on simulation of the antenna characteristics using FEKO electromagnetic (EM) software. Additionally, an equivalent circuit model of the antenna is also obtained and simulation of the input impedance on ADS software shows good agreement with the EM simulator. It is found that the radiation pattern, of the loop antenna changes significantly with the conductivity of the medium, from freshwater to seawater. The loop antennas were built with baluns and tested in freshwater, where the insertion loss between two identical antennas and the radiation pattern of one of them were also measured. The results show good agreement with the simulations.

Section: Water Propertiesmentioning

confidence: 99%

Antenna design for underwater radio communications

Inacio

et al. 2016

OCEANS 2016 - Shanghai

“…For this particular case, the electrical properties of PLA were assumed to be r = 2.54 and tan δ = 7.4 × 10 −3 , which are averages for the ranges of values reported in [5]. Seawater properties are exploited in [6], where an average value of σ = 4 S/m is considered for conductivity and relative permittivity is chosen to be r = 81.…”

Section: Proposed Methodsmentioning

confidence: 99%

Design and optimization of air core spiral resonators for magnetic coupling wireless power transfer on seawater

2016 IEEE Wireless Power Transfer Conference (WPTC)

Pessoa

et al. 2016

This paper focuses on the design of high quality spiral resonators for maximising wireless power transfer efficiency between an AUV and an underwater docking station. By using 3D electromagnetic simulations and numerical analysis, the relevant parameters for quality factor computation are extracted. The impact of different variables on a spiral resonator's quality factor is assessed, allowing to conclude on the optimum design parameters to achieve optimum efficiency on the power transmission through magnetic coupling. This work will contribute to enable the development future AUV wireless charging systems, which will allow for an improvement of AUV's range and endurance while ensuring lower operational costs.

“…4. The surrounding medium was set as salt water with a conductivity of σ = 4 S/m and relative permittivity of r = 81 [7]. The inner diameters of 5 and 15 turn inductors were swept in the range of 5 ≤ D inner ≤ 7 cm for the former case and 5 ≤ D inner ≤ 9 cm for the latter.…”

Section: B Simulation Assessmentmentioning

confidence: 99%

Assessment of design trade-offs for wireless power transfer on seawater

OCEANS 2016 MTS/IEEE Monterey

Pessoa

et al. 2016

In this work we propose a method for maximization of the efficiency of an underwater wireless power transfer system that has to cope with load changes, quality factor and coupling coefficient deviations. By means of 3D electromagnetic simulation and numerical computation, parameter analysis is accomplished using different compensation methods, namely series-series, series-parallel and parallel-parallel. Moreover, a linear load profile is assessed as a proof of concept applicable to more complex load behaviours. For this linear load variation a maximum measured average efficiency of 82% was obtained throughout the entire battery state of charge. Electronics and full system considerations are also presented. Finally, a good agreement between theoretical predictions of the proposed method, simulation assessment and measurement results was verified.