We have always treated the S-parameter data output of our ENA as a power ratio (using "10 * log()") rather than a voltage ratio (using "20 * log()"). Where is it explicitly stated that the ENA's S-parameter output is a power ratio? All network analyzer training material specifies voltage ratio definitions for the S-parameters, and I do not see an explicit definition of this ratio in the equipment's user guide.

Hello,

If your goal is conversion of the underlying real and imaginary complex pairs then use 20*Log10 to convert real and imaginary parameters to LogMag.

The following FAQ:

What are the equations that relate Real and Imaginary data pairs to Log Magnitude, Polar, Phase, and Smith Chart formats?marker) to Log Magnitude, Polar, Phase, and Smith Chart formats?

Format

^{See Note 1}Magnitude

_{10}((Re^{2 }+ Im^{2}))^{1/2}_{Cell1},Im_{Cell1}))))(dB)^{-1}(Im/Re) or arctan (Im/Re)Case of Re>0 and IM<0, tan

^{-1}(Im/Re) or arctan (Im/Re)Case of Re<0 and IM>0, tan

^{-1}(Im/Re)+180 or arctan (Im/Re)+180Case of Re<0 and IM<0, tan

^{-1}(Im/Re)-180 or arctan (Im/Re)-180_{Cell1},Im_{Cell1})*180/PI()(Degree)^{2}+ Im^{2}))^{1/2}Phase = tan

^{-1}(Im/Re) or Phase = arctan (Im/Re)_{Cell 1},Im_{Cell 1})))Phase = ATAN2(Re

_{Cell 1}, Im_{Cell 1})*180/PI()Chart

(Marker)

((1-Re

^{2}-Im^{2}) /((1-Re)^{2}+Im^{2})) * Z_{0}Reactance = X =

((2*Im) /((1-Re)

^{2}+Im^{2})) * Z_{0}_{Cell 1},2)-POWER(Im_{Cell 1},2)) /(POWER((1-Re

_{Cell 1}),2)+POWER(Im_{Cell 1},2)))*Z_{Cell 1}Reactance = (2*Im

_{Cell 1}) /(POWER((1-Re

_{Cell 1}),2)+POWER(Im_{Cell 1},2)))*Z_{Cell 1}Smith

Chart

(Marker)

Inductance (L)

Capacitance (C)

X < 0, C = 1/(2*pi*f*X)

^{Note 1}^{The references to ReCell 1, ImCell 1, and Cell 1 refer to the real and imaginary data pair numeric values that have been entered into specific cells in the Microsoft Excel data sheet!}The following is an example of data stored to a disk for a three-point trace:

^{}