Antenna arrangement for wireless powering

Abstract

An antenna arrangement for transmitting energy is described. The antenna arrangement includes a planar array of two or more rectangular loop antennas, adapted to transmit energy at low frequencies via non-radiative resonant coupling and at high frequencies via radiative coupling. The low frequencies correspond to a wavelength with half of the wavelength being larger than the longest rectangular loop antenna dimension and the high frequencies correspond to a wavelength with half of the wavelength being approximately equal the longest rectangular loop antenna dimension. The antenna arrangement also includes a feeding network connected to the planar array, which includes a phase shifting means for providing a phase difference between signals at the high frequencies to be transmitted by different rectangular loop antennas of the planar array, whereby the amount of phase difference is related to the distance of the rectangular loop antennas to a focal point in the near-field of the planar array. The antenna arrangement also includes means adapted for distributing the signals applied to the feeding network.