Novel measurement technique of WPT circuits using VNA and its data transformation into 0-ohm system

A measurement method for wireless power transfer (WPT) system with 0-ohm source impedance is shown. WPT systems are often designed by the BPF design theory and a vector network analyzer (VNA) is normally used for measurement. Here, some difficulty comes up for 0-ohm system that is common for high-efficient switching power sources. This paper describes the transmitted power and the transmission efficiency of 0-ohm system which are calculated by S parameters measured by VNA. The method is very simple and is applicable not only for 0-ohm system, but also for other impedance systems.