A figure-of-eight flexible coil for a magnetostrictive torque sensor

In this paper, a design to obtain a multi-turn, thin pickup coil system equivalent to the coils by using a flexible printed circuit board (PCB) having two conducting layers is presented. The coils are of the form of figure-of-eight and coupled orthogonally. Therefore, two overlapping parts of conductors occur at the center of each of coils. In the proposed design, this problem is solved by making a good use of two conducting layers of a flexible PCB. A coil system fabricated is tested by combining it to a shaft with a thin magnetic sleeve on it. The obtained results are satisfactory for a practical use.