Described herein are improved configurations for a resonator enclosure for wireless high power transfer that includes a support plate, a sheet of good conductor positioned on one side of the support plate, a separator piece for maintaining a separation distance between the resonator and the sheet of good conductor, and a cover of a non-lossy material covering the resonator, the separator, the sheet of good conductor and attached to the support plate, wherein the size of the sheet of good conductor is larger than the size of the resonator.