High-Impedance Wireless Power Transfer Transmitter Coils for Freely Positioning Receivers

In this letter, a wireless power transfer (WPT) system based on two high-impedance coil (HIC) - cable loop antennas with modified shield as transmitters (Tx)s and spiral receiver (Rx) is proposed discussed. Utilizing features of HIC at its parallel-circuit resonance frequency, we design the Tx in way that absence Rx, input impedance very high compared to case when Rx near Tx. This feature offers possibility for free positioning over an array Txs auto self-activation de-activation Txs, leading highly efficient performance. To verify solution, have designed, fabricated, experimentally tested WPT HICs one Rx. The operates high-frequency range (around 280 MHz) near-field coupling regime. measured averaged efficiency prototype higher than 93%. simple, cheap, does not require any control circuit tuning position changes.