An electromagnetic device includes a jig and multiple wires. The jig includes a center member and coil-separating blocks. The coil-separating blocks protrude from the center member and are separated from each other to provide a coil channels. Each of the wires is wrapped on the jig, around the center member, and in one of the coil channels to form one of a multiple coils. Each of the coils is configured to connect to an electromagnetic navigation system and generate respective electromagnetic fields to be emitted relative to a subject.