A wireless power transfer system based on inductive coupling for powering implantable medical devices of diverse application is proposed. The system is composed of two resonators based with circular spiral printed on a dielectric substrate. With operation corresponding to the frequency range of medical applications in implants of 403 MHz, and an RF power transfer efficiency (PTE) greater than 50.0 % is obtained with a total reach of 8.0 mm into living tissue. Numerical studies and analyses are carried out in order to investigate the influence of tissues on the frequency response and efficiency of the presented resonators. Through simulations it is possible to establish the maximum input power limit of 120.0 mW of the model to comply with the safety limits of the specific absorption rate (SAR) below 2.0 W/kg. In general, the simulated and measured results demonstrate a good level of agreement. Comparative analyses and conclusions are presented and discussed.