Empirical Performance Survey of Inductive and Capacitive Wireless Power Transfer Systems

Wireless power transfer (WPT) continues to gain momentum across diverse applications, from milliwatt biomedical implants to tens-of-kilowatts electric vehicle charging. Within short-distance WPT, inductive wireless power transfer (IPT) and capacitive wireless power transfer (CPT) are the two dominant approaches, each with distinct advantages and limitations. This paper surveys the recent experimental progress in IPT and CPT reported in 133 peer-reviewed publications between 2020 and 2025. The survey focuses on system-level demonstrations that include quantitative performance metrics, with particular emphasis on DC-DC efficiency. Key parameters, such as power level, operating frequency, transfer distance, and coupler area, are systematically compared. The survey reveals that IPT remains dominant in very high-power and larger-gap realizations, while CPT has expanded beyond its traditionally short-gap applications and now competes directly with IPT across a wide range of power levels. Both techniques routinely achieve efficiencies exceeding 90% under diverse operating conditions, underscoring their growing maturity and potential to address future WPT demands. The presented data reveal measurable shifts in achievable power and efficiency in the last decade, reflecting the maturation of CPT and the influence of wide-bandgap power electronics. These findings establish an updated data-driven performance envelope derived from experimentally demonstrated systems, providing a reference for future experimental and modeling studies in short-range WPT.