Field decay characteristics of wireless power transfer emissions over earth sites and in semi-anechoic chambers

Wireless power transfer (WPT) systems need to be tested for compliance with radiated electromagnetic emission regulations and standards. Understanding of the fundamental wave decay characteristics of WPT emissions over real earth sites and the effects of semi-anechoic chambers are important issues, as standardization bodies such as ANSI c63.30 committee are drafting measurement procedures for inductive WPT radiated emissions at frequencies up to 30 MHz. This paper presents measurement and simulation investigations of vehicle WPT frequency field decay characteristics, using a polarized vehicle WPT system over an earth site at up to 300m for radial, transverse and vertical polarizations, and effects of ferrite-lined metallic chamber walls on field decay characteristics.