An apparatus for wirelessly charging a battery, said apparatus comprising: a transmitter including: a communication component; and an antenna, comprising: a plurality of antenna sub-units, each of the plurality of antenna sub-units comprising: a helical shaped three-dimensional resonator element (406, 1304) configured to radiate a radio frequency, RF, wireless power signal, the RF wireless power signal having a frequency greater than 1 GHz; a substrate (408, 1312) embedding the resonator element, wherein the substrate is made of a dielectric material; and a wall that surrounds at least a part of the substrate, wherein: the wall is made of a metallic material that is distinct from the dielectric material, and the wall is configured to act as a waveguide or quasi-waveguide structure for the RF wireless signal; wherein at least one wall of each of the plurality of antenna sub-units is shared by adjacent two antenna sub-units of the plurality of antenna sub-units; wherein at least one substrate included in at least one of the plurality of antenna sub-units has a different permittivity than a remainder of the plurality of antenna sub-units other than the at least one of the plurality of antenna sub-units; wherein the antenna is configured to be controlled by the transmitter that communicates with a receiver through the communication component of the transmitter to produce a directed pattern to form an energy pocket comprising a combination of peak signals of a plurality of wireless power signals at a location of the receiver that charges an electronic device; and wherein the three-dimensional resonator element (406, 1304) is configured to radiate the RF wireless power signal for use in charging a battery, wherein each of the plurality of antenna sub-units further comprises a base on which is the substrate is positioned, the base operating as a ground plane. a communication component; and an antenna, comprising: a plurality of antenna sub-units, each of the plurality of antenna sub-units comprising: a helical shaped three-dimensional resonator element (406, 1304) configured to radiate a radio frequency, RF, wireless power signal, the RF wireless power signal having a frequency greater than 1 GHz; a substrate (408, 1312) embedding the resonator element, wherein the substrate is made of a dielectric material; and a wall that surrounds at least a part of the substrate, wherein: the wall is made of a metallic material that is distinct from the dielectric material, and the wall is configured to act as a waveguide or quasi-waveguide structure for the RF wireless signal; a helical shaped three-dimensional resonator element (406, 1304) configured to radiate a radio frequency, RF, wireless power signal, the RF wireless power signal having a frequency greater than 1 GHz; a substrate (408, 1312) embedding the resonator element, wherein the substrate is made of a dielectric material; and a wall that surrounds at least a part of the substrate, wherein: the wall is made of a metallic material that is distinct from the dielectric material, and the wall is configured to act as a waveguide or quasi-waveguide structure for the RF wireless signal; the wall is made of a metallic material that is distinct from the dielectric material, and the wall is configured to act as a waveguide or quasi-waveguide structure for the RF wireless signal; wherein at least one wall of each of the plurality of antenna sub-units is shared by adjacent two antenna sub-units of the plurality of antenna sub-units; wherein at least one substrate included in at least one of the plurality of antenna sub-units has a different permittivity than a remainder of the plurality of antenna sub-units other than the at least one of the plurality of antenna sub-units; wherein the antenna is configured to be controlled by the transmitter that communicates with a receiver through the communication component of the transmitter to produce a directed pattern to form an energy pocket comprising a combination of peak signals of a plurality of wireless power signals at a location of the receiver that charges an electronic device; and wherein the three-dimensional resonator element (406, 1304) is configured to radiate the RF wireless power signal for use in charging a battery, wherein each of the plurality of antenna sub-units further comprises a base on which is the substrate is positioned, the base operating as a ground plane.