用于展示利用史密斯圆图进行射频传输线系数分析，包括信噪比，回波损耗等功能。(In order to complete both of the assignments of Smith chart at the same time, I decided to write this essay to expound my experience to use Smith chart while recording my process about programming a program that can compute VSWR, Return Loss and other parameters by input Z0 and ZL, and calculate Zin by input f0 and line length. In the process of programming by Matlab, the principle of solving RF problem by using Smith chart will emerge step by step.)