Dual-band WPT system using Semi-H DGS for Biomedical Applications

A dual-band wireless power transfer (WPT) system utilizing semi-H shaped Defected Ground Structure (DGS) for biomedical applications is presented in this paper. The proposed design uses magnetic resonance coupling to achieve medium-range power transfer. The semi-H design increases the inductance of the circuit, which results in higher efficiency. To reduce the overall size of the prototype, the DGS is loaded with external surface mounted chip (SMD) capacitors. The design and optimization is backed up by an equivalent circuit which mimics the behaviour of the proposed WPT system. A prototype of the system operating at frequencies of 433 MHz and 700 MHz is developed with size 31 × 13 mm². The measurement of the WPT system gives respective efficiencies of 71% and 72% at 433 MHz and 700 MHz at a distance of 16 mm. These results demonstrate substantial improvement in the efficiency of multi-band DGS WPT systems reported so far.