This paper introduces a high-frequency coaxial transformer (HFCT) with a power ef?ciency of >99.5% and an operational frequency between 100-300 kHz. The power rating of the HFCT can be easily scaled from 2.5 to 20 kW by adapting its simple symmetrical struc- ture. The introduced HFCT is suitable for use with converters in electric vehicle on-board charging systems. It easily ful?lls the design requirements of being lightweight, compact, and having a high power density and achieved a volume reduction of 75% in comparison with commercial products Furthermore, the electromagnetic interferences are increasing with the increased operating frequency, and an inserted copper Faraday shield is used to deal with this issue (an 80.6% reduction of intra-winding capacitance was achieved). A shielding analysis, with a focus on the insertion losses, is undertaken by utilizing ?nite element method based numerical techniques.