Measurement of resonator parameters for wireless power transmission system

A WPT design method by oscilloscope measurement is shown. Because a WPT system can be designed based on the BPF design theory, the resonant frequency, unloaded Q, external Q and coupling coefficient k of coupled resonators are the key parameters. Though they are usually measured by use of a vector network analyzer (VNA) in terms of S parameters, the present paper reports that these parameters can be measured by an oscilloscope, too. A vector network analyser is not popular in the lower frequency band such as around 1MHz where WPT systems are operating, and hence, oscilloscope measurement could be more acceptable in this field.