Efficient Compact Radiative Near-Field Wireless Power Transfer to Miniature Biomedical Implants

This letter proposes a compact transmitter (Tx) for radiative near-field wireless power transfer (WPT) to deep-implanted biomedical applications. A multiple-loop radiating plane and slotted-ring excitation ring structure are analyzed to generate a strong focused field inside the human tissue without using any controllable circuit. Meanwhile, an impedance matching network is implemented on the Tx side to obtain the antenna operation and enhance the PTE at 1.9 GHz. Furthermore, a miniaturized receiver is employed to verify the proposed Tx's performance. Experimental results show that our proposed WPT can supply power in a distance of up to
${\text{0.127}}\lambda _{0}$
with a PTE of −20.12 dB. Finally, our proposed WPT system is compared with other works in near-field WPT to show our high PTE and compact antenna's dimensions.