Triple-Band Near-Field Wireless Power Transfer System Using Coupled Defected Ground Structure Band Stop Filters

For the first time, a triple-band near-field wireless power transfer (WPT) system is presented using coupled triple-band defected ground structure (DGS) bandstop filters (BSF). A triple-band DGS-BSF is possible through creating a frequency dependent effective inductance, which appears with lower inductance at higher frequencies. When we couple two triple-band DGS-BSFs in a back-to-back configuration, a triple-band DGS-WPT system is created. We verify the proposed DGS-WPT system through good agreements between electromagnetic simulations and measurements. The measured WPT efficiencies are 68%, 60%, and 65% at 100.8 MHz, 140.7 MHz, and 182.2 MHz, respectively at a WPT separation distance of 30 mm. Each of the WPT transmitter and receiver has a size of 50 × 50 mm².