In some applications, power transfer from the stationary side to the rotary side is needed. To avoid the use of mechanical slip ring, a CPT (contactless power transfer) device was proposed. Besides power transfer, communication between both sides is also important. With special design, the flux created by the power coil won’t be coupled with the signal coil. This idea is verified with analytical calculation through the equivalent magnetic circuit. Then the model is simulated with the finite element method. The results show that with proper design, the magnetic coupling of two coils can be reduced to a very low value.