This paper presents a design of magnetic resonant wireless power transfer (MR-WPT) system operating at 6.78
MHz with flexible resonator coils. The resonator coils are fabricated on an FR-4 substrate with a very thin
thickness of 0.2 mm; therefore, they can be bent at various angles. With the bendable resonator coils, the configuration
of the MR-WPT system will be more flexible, thereby increasing the applicability. However, the
inductance, resistance, quality factor, and mutual inductance of the coils will be changed with the bending
angle, thereby affecting the performance of the MR-WPT system. Detailed investigations of these changes were
conducted by both simulation and experiment. Thus MR-WPT systems with flexible resonators can be
designed for optimum performance. This proposed MR-WPT system can be applied in situations where system
configuration requires high flexibility. Moreover, a bent resonator system can perform better than a flat
resonator system in the inward bending configuration.