A transformer assembly includes a substrate having a first surface and an opposing second surface, a first spiral wound inductive coil formed on the first surface, and a second spiral wound inductive coil formed on the first surface; the first and second spiral wound inductive coils forming a double spiral arrangement on the first surface such that the first coil is inductively coupled to the second coil. An RF coil including the transformer assembly and a method of fabricating the transformer assembly are also described.