**6. Conclusions**

In this paper, a steady-state matrix analysis method suitable for class-E power amplifier was introduced. Compared with the analysis process of the working principle of a class-E power amplifier, non-ideal factors are considered in this method, such as inductance resistance and leakage current, etc. The experimental results are more accurate. Based on steady-state matrix analysis, the output characteristic of two kinds of class-E power amplifier circuits were analyzed and optimized. The experimental results show that the output power of the two types of class-E power amplifier increased by 2.29 W (8.23%) and 1.91 W (7.35%), respectively, while the output efficiency had no obvious change. The B-field strength of the systems with two types of class-E power amplifier before and after optimization meets the ICNIRP-2010 standard.

**Author Contributions:** F.W. conceived and designed the study, and this work was performed under the advice of and regular feedback from him. R.L. was responsible for the simulations.

**Funding:** This work was supported by the Basic Research Program of Jiangsu Province (No. BK20180485), Jiangsu Provincial Key Laboratory of Smart Grid Technology and Equipment Project, and the Fundamental Research Funds for the Central Universities (No. 30919011241).

**Conflicts of Interest:** The authors declare no conflict of interest.
