Smartphones are gradually becoming the most important personal device. In the first quarter of 2013, global smartphone shipments reached 216 million, which is approximately twice as large as in 2011.[1] In the absence of breakthroughs in mobile phone batteries nowadays, mobile phones are unable to run for long periods. For devices to work continuously, the convenience of their charging method is important. Wireless charging is a better solution to get rid of the charging cable and the convenience it brings. One of the main objectives of this paper is to find ways to improve the efficiency of wireless charging by analyzing different designs of wireless charging models, dual coil charging lines, dual charging frequencies, and coupling coefficients as well as the influence of the coil on charging. Based on the review of the different designs, it was found that the dual coil design can improve the charging efficiency in terms of quantity. The dual-charging frequency design improves the versatility of wireless charging. Variations in the number of turns and coupling coefficients of the coils can improve the efficiency of the transmission.