s-parameter has problem in cst

i used lineimpedance macro.
right of the picture S1,1 & S2,2 is 16.39 ohm.
but smith position is not 16.39ohm.

why did happen this result?

Because you confuse Characteristic Impedance with Input Impedance of a Transmission Line terminated with 50 Ohm.

i'm not understand
so please let me know in detail

You calculated Characteristic Impedance of a Coaxial transmission Line.This impedance depends on physical parameters of coaxial line.( dielectric coefficient,inner and outer radius,conductor diameter etc.). But when you simulate this Transmission Line in a EM simulator you usually use 50 terminating impedance at the end of the Transmission Line and therefore Input Impedance of this transmission line seems different than characteristic impedance.If you calculate input impedance of a transmission line with a characteristic impedance different than 50 ohm, you will find approx. same value.Refer to EM text book.

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