The present invention refers to an apparatus for use in wireless energy transfer to power an electronic device. The apparatus comprises a transmitting assembly configured to transmit electromagnetic energy, whereby the transmitting assembly comprises a transmitting resonant coil providing a first conductor and a first electrical insulating medium between coil turns of said first conductor. The apparatus further comprises a receiving assembly magnetic resonance coupled to the transmitting assembly, whereby the receiving assembly comprises a receiving resonant coil providing a second conductor and a second electrical insulating medium between coil turns of said second conductor. A first capacitor is electrically connected to the first conductor and a second capacitor is electrically connected to the second conductor. The first and/or second insulating medium comprises one or more dielectric materials that is solid with a polygonal cross section. Further the first and/or second insulating medium provides a dielectric dissipation factor of 0.01 or less. The first and/or second conductor has a thickness T of less than 0.0508 cm [0.020 inches] and a width W of 1.27 cm [0.5 inches] or less, wherein the transmitting and/or receiving resonant coil has a diameter of 7.62 cm [3 inches] or less.
