**5. Conclusions**

This paper introduced scaling-factor and design guidelines for shielded-CPT. The theoretical design and analytical approach were described in detail with a simplified circuit model for analytical purposes.

From the EF and stress voltage of the shield-coupler plates, it was found that the stress voltage was proportional to the parasitic capacitance, *CP*. The distance between the shield plate and coupler, *dSC*, needs to be minimized to obtain a thin and compact module. However, a larger *CP* results in a strengthened stress voltage, which is limited to 30 kV/cm for safety considerations.

The power loss in the series inductor was investigated and found to be proportional to the inductance value. However, increasing *CP* will reduce the value of *L* and result in low-power loss. The scaling used in the design was presented together with various load results; it was found that increasing *RL* will decrease the inductor's power loss.

Process and procedure of scaling and designing the shielded-CPT was followed by analysis of the behavior of each factor, including voltage, current, power, parasitic capacitance, and system efficiency. Finally, the design guidelines for the shielded-CPT system were introduced. The design example for the hardware implementation was conducted successfully for the proposed method. It was found that, using these guidelines, an impressive hardware-parameter calculation and implementation was obtained. Thus, the proposed method can be recommended for designing shielded-CPT systems with scaling-factor and safety consideration.

**Author Contributions:** Conceptualization, A.M. and R.H.; methodology, A.M. and R.H.; validation, A.M. and S.A.; visualization, A.M.; writing—original draft preparation, A.M.; writing—review and editing, S.A. and R.H.; supervision, R.H. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Acknowledgments:** The authors would like to thank Mitsuru Masuda and the members of Automotive System and Device Laboratories, Furukawa Electric Co., Ltd. through their technical support. The Ministry of Research and Technology, Republic of Indonesia through the RISET-Pro scholarship support to A.M. (World Bank Loan No. 8245-ID).

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