A resonant induction wireless power transfer coil comprising: a 2n-layer coil stack, where n is a positive integer, comprising: a dielectric connected to operate in a differential mode and having a first side and a second side, a first conductor pattern comprising a first plurality of conductors wound in a spiral on the first side of the dielectric to provide a forward current path conductor, and a second conductor pattern comprising a second plurality of conductors wound in a spiral on the second side of the dielectric to provide a return current path conductor, the second conductor pattern being aligned with the first conductor pattern whereby the second conductor pattern reinforces magnetic flux generated by the first conductor pattern, wherein the first and second conductor patterns are placed relative to one another so as to provide flux transmission in a same direction; and a capacitance between each layer of the coil stack selected such that the 2n-layer coil stack is self-resonating at a designed self-resonating frequency f r = 1 ÷ 2 π √ LC that is being used for wireless power transfer with another wireless power coil of a wireless power transfer apparatus, where L= equivalent coil inductance of the 2n-layer coil stack and C = equivalent capacitance of the 2n-layer coil stack, and characterised in that the first and second conductor patterns are not directly electrically connected. a 2n-layer coil stack, where n is a positive integer, comprising: a dielectric connected to operate in a differential mode and having a first side and a second side, a first conductor pattern comprising a first plurality of conductors wound in a spiral on the first side of the dielectric to provide a forward current path conductor, and a second conductor pattern comprising a second plurality of conductors wound in a spiral on the second side of the dielectric to provide a return current path conductor, the second conductor pattern being aligned with the first conductor pattern whereby the second conductor pattern reinforces magnetic flux generated by the first conductor pattern, wherein the first and second conductor patterns are placed relative to one another so as to provide flux transmission in a same direction; and a dielectric connected to operate in a differential mode and having a first side and a second side, a first conductor pattern comprising a first plurality of conductors wound in a spiral on the first side of the dielectric to provide a forward current path conductor, and a second conductor pattern comprising a second plurality of conductors wound in a spiral on the second side of the dielectric to provide a return current path conductor, the second conductor pattern being aligned with the first conductor pattern whereby the second conductor pattern reinforces magnetic flux generated by the first conductor pattern, wherein the first and second conductor patterns are placed relative to one another so as to provide flux transmission in a same direction; and a capacitance between each layer of the coil stack selected such that the 2n-layer coil stack is self-resonating at a designed self-resonating frequency f r = 1 ÷ 2 π √ LC that is being used for wireless power transfer with another wireless power coil of a wireless power transfer apparatus, where L= equivalent coil inductance of the 2n-layer coil stack and C = equivalent capacitance of the 2n-layer coil stack, and characterised in that the first and second conductor patterns are not directly electrically connected. <EOS>