Mobile wireless power transfer based on line-coupled or line/resonator-coupled structure

Microwave directional coupler or directional filter is diverted to wireless power transfer systems. They are changed into broad-side coupled from the original edge coupled configuration so as to increase the coupling coefficient first of all. Additional important modifications include making the power transmission line straight and uniform, and moreover, preparing the air gap between two substrates so as to ensure the free sliding movement of the power receiving unit. These modifications destroy circuit matching at each port, which should be retrieved introducing circuit elements only to the power receiving unit. Satisfactory matching has been obtained for both line-coupled and line/resonator-coupled configurations.