Magnetic resonant–wireless power transfer for transparent laptop applications using μ-metal mesh film

In this study, we designed transparent resonators using a μ-metal mesh film (μ-MMF) for magnetic resonant–wireless power transfer (MR-WPT) for transparent laptop applications. The μ-MMF transparent electrode has optical transmittance of 65% and sheet resistance of 0.18 Ω/□. For realizing a transparent laptop, transparent acrylic (ɛ_r = 2.6, tan δ = 0.009) was used as a laptop case, and the μ-MMF was used as both the transparent ground and receiver (Rx) resonators in the display and body parts of the laptop. The transparent Rx resonators were configured in three combinations (loop resonator [LR], loop resonator with a ground [LRG], and slit ground resonator [SGR]) for the performance comparison, and the operation frequency of the transparent Rx resonators was optimized to 6.78 MHz using capacitors. We measured the transfer efficiency (TE) according to the transfer distance between the Tx and Rx parts, from 5 to 70 cm. The maximum TE of the MR-WPT with the transparent LR was 41%. For practical applications including ground in the laptop, the TE of the MR-WPT with the transparent LRG is also measured, and it is nearly zero. Therefore, we designed a transparent SGR that operates as both a resonator and a ground simultaneously; the TE of the MR-WPT with transparent SGR is improved by 27% compared with the LRG in practical applications including ground planes.