The Mizuhashi-Smith Chart

Two years prior to Phillip Hagar Smith's proposal in 1939, Mizuhashi Tosaku, an engineer of Japan Wireless Telegraph Corporation, published a paper which illustrated a nomogram obviously equivalent to the normalized impedance Smith chart as "a chart of circular curves of reflection coefficient γ corresponding to Z01 (and Z02)" in Figure 1 as a tool for graphically calculating impedance[1]. Therefore, in Japan, there have been claims that the Smith chart should be called the Mizuhashi chart or the Mizuhashi-Smith chart [2].

[1] Mizuhashi, T., "Theory of four-terminal impedance transformation circuit and matching circuit," The Journal of the Institute of Electrical Communication Engineers of Japan, pp.1053-1058, December 1937 (in Japanese).
[2] Okamura, S., " "Smith chart" may have origin in Japan,"  The Journal of the Institute of Electrical Communication Engineers of Japan, pp.768-769, August 1959 (in Japanese).

Mizuhashi-SmithChart.JPG


@morikuni_net on Twitter