In modern medicine, the batteries in implantable devices are replaced with wireless power transmission (WPT) technology. The resonance-based WPT method is widely used in biomedical implantation applications as it enables the mid-field operation within the human body. The shape and misalignment of the implantable coil due to human breathing activity and body moments are the main obstacles to achieve the high power transfer efficiency. In this paper, we designed, optimized, and analyzed the spherical and circular shaped implantable coils to mitigate the misalignment issue. Results show that the spherical shaped implantable coil has superior performance under misalignment situations when compared to the circular shaped implantable coil.