We evaluate RF amplifiers using actual equipment and a simulator (ADS).
Since there are few types of inductance values for air-core coils that can be used in matching circuits over 100W, we make our own air-core coils by winding copper wire, and we also measure them with a VNA to obtain their S-parameters when simulating.
When measuring coils with small inductance values (about 10nH) using the series-through method, there is a lot of noise, so we measured them using the shunt-through method.
I think that conversion is necessary to use S-parameters measured using the shunt-through method in series, but it seems that the conversion is not done correctly.
To check whether the conversion is done correctly, we tried the following.
-Perform S-Zdut and Z-Y conversions for the S-parameter series and shunts provided by the manufacturer (e.g. Johnson Technology's R14S100-H-SER, R14S100_SNT). -Compare S-parameter series and S-parameter shunt → series.
S-Zdut Zdut(series)=100*(1-S21)/S21 Zdut(shunt)=25*S21/(1-S21)
Z-Y conversion http://math7755.s1010.xrea.com/SYZ_para3/SZY_para3.htm
20250527 Addendum
When I measured the Re and Im of the Coilcraft air core coil 1010VS46N using an impedance analyzer and compared the converted values with the manufacturer's S parameters, the characteristics were very similar.
The measurement range of the impedance analyzer is up to 300MHz, so the frequency range of the graph on the right is up to 300MHz.
Impedance analyzer: IM7850A
