Dual-Band Transmitter for Wireless Power Transfer to Biomedical Implant Applications

Abstract

This letter presents a dual-band transmitter (DB-Tx) for wireless power transfer (WPT) to biomedical implants. The DB-Tx operates at <inline-formula><tex-math notation=LaTeX>$\rm{1.7}~GHz$</tex-math></inline-formula> (LF-band) and <inline-formula><tex-math notation=LaTeX>$\rm{2.1}~GHz$</tex-math></inline-formula> (HF-band) to power implantable devices in deep and shallow implantation, respectively. A bipolar concentric loop (BCL) radiating plane is employed to obtain field-focusing characteristics at dual frequencies, and hence enhance the power transfer efficiency (PTE). Furthermore, a wide-band implantable receiver (Rx) is implemented to verify DB-Tx's performance. Experimental results show that, by utilizing the DB-Tx, the transmission range can be extended three times in HF-band and 30% in LF-band, compared to the Tx operating at a single frequency band. The Rx can receive power with the PTE of <inline-formula><tex-math notation=LaTeX>$-14.7~dB$</tex-math></inline-formula> and <inline-formula><tex-math notation=LaTeX>$-23~dB$</tex-math></inline-formula> at <inline-formula><tex-math notation=LaTeX>$\rm{10}~mm$</tex-math></inline-formula> and <inline-formula><tex-math notation=LaTeX>$\rm{40}~mm$</tex-math></inline-formula> implantation depth, respectively. IEEE