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

letter presents a dual-band transmitter (DB-Tx) for wireless power transfer to biomedical implants. The DB-Tx operates at 1.7 GHz (LF-band) and 2.1 GHz (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 wideband 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 with the Tx operating at a single frequency band. The Rx can receive power with the PTE of -14.7 and -23 dB at 10 and 40 mm implantation depth, respectively.