Metal cover design of mobile phone for wireless power transfer

摘要

This letter proposes a method of designing a metal cover of mobile phone for wireless power transfer (WPT). To investigate the effect of metal cover on WPT, the efficiency is extracted by changing the size and shape of the metal cover. As a result, the factor of reducing the efficiency of the WPT is the cover design adjacent to the receiving coil. Two cover designs are proposed to maximize efficiency when covering the entire mobile phone with metals according to the via positions. The first design is to divide the metal cover into five metal patches. A large metal patch is located in the middle and two small metal patches are placed at the top and bottom respectively. The second design is to divide the metal cover into three metal patches and the metal patches are placed at the top, middle, and bottom. The efficiency of the WPT is measured by fabricating the proposed structures. At the frequency of 6.78 MHz, the measured efficiency is 65% for the first design, and 63% for the second design.