Planar rotary transformer

One example device includes a rotor platform that rotates about an axis of rotation. The device also includes a rotor coil comprising a first plurality of conductive loops disposed along a planar mounting surface of the rotor platform. The device also includes a stator platform and a stator coil comprising a second plurality of conductive loops disposed along a planar mounting surface of the stator platform. The rotor coil and the stator coil are coaxially arranged about the axis of rotation. The stator coil remains within a first predetermined distance to the rotor coil in response to rotation of the rotor platform. The device also includes a magnetic core extending along the axis of rotation and through the stator coil. The magnetic core remains within a second predetermined distance to the stator coil in response to rotation of the rotor platform.