Maximum Wireless Power Transfer to the Implantable Device in the Radiative Near Field

This letter presents a wireless power transmission (WPT) system with enhanced power transmission efficiency (PTE) for powering implantable devices in the radiative near field. The gain of the implantable receiving antenna is improved by 8 dB through utilizing a parasitic patch. The system is further optimized by maximizing the PTE between the transmitting antenna array and the implantable receiving antenna, yielding an optimal excitation distribution for the transmitting antenna array. Compared to a reference WPT system with the transmitting array fed by the uniform amplitude and phase, the PTE of the optimized system is about 1.3 times higher than that of the reference one.