Enhancement of Wireless Power Transmission by Using Novel Multitone Approaches for Wireless Recharging

This letter presents novel multitone wireless power transmission (WPT) approaches to enhance the induced voltages for wireless recharging. Effectiveness of the proposed approaches is demonstrated by using a dual-band (1.83/3.36 GHz) antenna of only 0.018λ
²
in size. Power conversion efficiency (PCE) represents a major challenge for WPT, especially at low input power levels. Our results indicate that PCE is related to the distributions and the combinations of input power spectrum. Therefore, a novel multitone powering system is developed to achieve a high output voltage. Experimental results indicate that the induced voltage can increase by 3.8 times over that of multitone WPT. Furthermore, wireless multitone powering can produce a 1.92-V output, i.e., an improvement of 14%, with a small average power of -5.3 dBm at 1.83 GHz.