An apparatus for imaging includes: a main magnet to generate a substantially uniform main B0 magnetic field through an examination region; and a coil system including a first coil layer and a second coil layer disposed substantially parallel to the first coil layer with a defined air gap in a radial direction, the first coil layer including a first coil array, the second coil layer including a second coil array, the first and second coil arrays being coupled and cooperating to selectively produce a prespecified B1 magnetic field within the examination region.