This invention involves a new design of a wireless power transfer system that can transfer power across the production packer along an oil pipe. It is difficult to apply power across production packer due to the obstruction but one can add coils at both sides of the production packer and deliver electric power via magnetic induction. The inducted magnetic field decays rapidly as the distance between the two coils increases. We introduce a soft ferrite layer on the metallic pipe section between the coils to enhance the magnetic coupling so that the wireless power transfer efficiency can be maintained at a sufficient level when the coil separation is relatively large.