Revisiting Two-Port Network Analysis for Wireless Power Transfer (WPT) Systems

This paper discusses the applicability of the two- port network model for the analysis of wireless power transfer (WPT) systems. The two-port network model has been extensively used to analyze microwave circuits, and identical principles have been applied to WPT. The standard gain parameters defined for the two-port networks are critically analyzed with regards to WPT systems. The usefulness and the practical limitations of the gain parameters are highlighted. In addition to power transfer efficiency (PTE), an alternative gain parameter, square voltage gain is defined to estimate the power transfer capability of the WPT system. The proposed performance indices are then computed in terms of generalized two-port network parameters along with a generalized optimization methodology. A case study is presented for the optimization of a WPT system with a repeater.