Antenna Arrangement for Wireless Powering

A method for charging a device having an antenna arrangement for receiving energy that includes at least one rectangular loop antenna adapted to receive energy at low frequencies via non-radiative resonant coupling and at high frequencies via radiative coupling, the low frequencies corresponding to a wavelength larger than twice a longest rectangular loop antenna dimension and the high frequencies corresponding to a wavelength approximately equal to twice the longest rectangular loop antenna dimension, the high frequencies being suitable for receiving energy transmitted from larger distances than the low frequencies, comprising:

• approaching the device with a powering station that includes an antenna arrangement for transmitting energy and operates at a frequency at which energy is transmitted via radiative coupling, wherein radiation is focused in a near-field of the antenna arrangement for transmitting energy, and wherein the antenna arrangement for transmitting energy comprises:
• a planar array of two or more rectangular loop antennas, each rectangular loop antenna adapted to transmit energy at the low frequencies via non-radiative resonant coupling and at the high frequencies via radiative coupling, the planar array so configured that a fixed focal area is created in front of an aperture of the planar array, the fixed focal area being in a near-field of the planar array;
• a feeding network connected to the planar array and comprising a phase shifter for providing a phase difference between signals at the high frequencies to be transmitted by different rectangular loop antennas of the planar array, wherein the amount of phase difference compensates for a difference between a distance of the rectangular loop antennas to a focal point in the fixed focal area in the near-field of the planar array and a distance of the focal point to the planar array;
• and
• a power divider/combiner adapted for distributing the signals applied to the feeding network.

Antenna arrangement for transmitting energy, comprising:

• a planar array of two or more rectangular loop antennas, each rectangular loop antenna adapted to transmit energy at low frequencies via non-radiative resonant coupling and at high frequencies via radiative coupling, the low frequencies corresponding to a wavelength larger than twice a longest rectangular loop antenna dimension and the high frequencies corresponding to a wavelength approximately equal to twice the longest rectangular loop antenna dimension, the high frequencies being suitable for transmitting energy over larger distances than the low frequencies, the planar array so configured that a fixed focal area is created in front of an aperture of the planar array, the fixed focal area being in a near-field of the planar array;
• a feeding network connected to the planar array and comprising 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, wherein the amount of phase difference compensates for a difference between a distance of the rectangular loop antennas to a focal point in the fixed focal area in the near-field of the planar array and a distance of the focal point to the planar array;
• and
• distribution means for distributing the signals applied to the feeding network.