S-Parameters for Calculating the Maximum Efficiency of a MIMO-WPT System: Applicable to Near/Far Field Coupling, Capacitive/Magnetic Coupling
Qiaowei Yuan
Abstract
S-parameters are members of a family of circuit network parameters. Other members are Z-parameters, Y-parameters, T-parameters, and ABCD-parameters <xref ref-type="bibr" rid="ref1" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">[1]</xref> . The first published description of S-parameters was in the thesis of Vitold Belevitch, in 1945 <xref ref-type="bibr" rid="ref2" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">[2]</xref> . Kaneyuki Kurokawa popularized the S-parameters referred to as <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">power waves</i> <xref ref-type="bibr" rid="ref3" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">[3]</xref> , making S-parameters much easier to apply to microwave engineering when port voltages and currents are difficult to define and measure.