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We demonstrate a new concept of an electromagnetic usage in the sea. The concept is characterized by sharing one pair of transmitting and receiving antennas for contactless communication and power transmission. The antennas are designed as electromagnetic (EM) high-Q resonators and the lowest resonant frequency is used for power transfer. The higher frequency band is used for signal communications. Using this concept, the efficiency of power transfer can be relatively high and the high transmission rate can be possible. As a test trial for verifying the above concept, a measurement system is set up and the power transfer and signal quality are evaluated. The results show the power efficiency can be over 40%, and the transmission rate can be 20 Mbps via seawater of the 5 cm's thickness. The proposed concept can be used to realize a compact and maintenance-free wireless usage between different underwater systems, such as autonomous underwater vehicles (AUVs), remotely-operated vehicles (ROVs) and mother ships.

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In this work we offer a simple analytical method which allows us to determine and study the effects of the selective switching of photonic stop-bands in multi-component photonic crystals (Mc-PhCs) of any dimensionality. The calculations for Mc-PhCs with low dielectric contrast have been performed in the framework of the model based on the scattering form factor analysis. It has been shown that the effects of selective switching of photonic stop-bands predicted theoretically and found experimentally before in three-dimensional (3D) Mc-PhC have a general character and may be observed also in one-dimensional (1D) and two-dimensional (2D) Mc-PhCs. It is found that 1D, 2D and 3D Mc-PhCs demonstrate unexpectedly similar quasi-periodic behaviour of photonic stop-bands as a function of the reciprocal lattice vector. A proper choice of the structural and dielectric parameters can create a resonance photonic stop-band determining the Bragg wavelengths, to which a photonic crystal can never be transparent.