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	Sパラメータ解析	スミスチャート
分野	電気工学	電気工学
系統	Process / pipeline	Process / pipeline
提唱年	1965	1939
提唱者	Kaneyuki Kurokawa	Phillip H. Smith
種類	Wave-based description of RF/microwave network behavior	Graphical tool for transmission line and impedance analysis
原典	Kurokawa, K. (1965). Power waves and the scattering matrix. IEEE Transactions on Microwave Theory and Techniques, 13(3), 194-202.	Smith, P. H. (1939). Transmission line calculator. Electronics, 12(1), 29-31.
別名	S-parameter, Scattering parameters, Network parameters	Impedance chart, Reflection coefficient chart
関連	3	3
概要	S-Parameters (Scattering Parameters) characterize RF and microwave networks by their transmission and reflection of voltage waves. Introduced by Kurokawa in 1965, S-parameters are ideal for high frequencies where wave effects dominate. Unlike impedance (Z), admittance (Y), or hybrid parameters, S-parameters are directly measurable with network analyzers, naturally account for characteristic impedance, and are intuitive for cascade analysis. S-parameters are the standard language of RF engineering.	The Smith Chart is a graphical tool for visualizing and manipulating complex impedances and reflection coefficients on transmission lines. Introduced by Phillip Smith in 1939, the chart maps the complex reflection coefficient plane to a circular chart, enabling intuitive graphical analysis of transmission line problems, impedance matching, and resonance conditions. Despite the advent of computers, the Smith Chart remains invaluable for understanding transmission line physics and designing RF circuits.