本函数在matlab实现阻抗圆图，通过调用switch（）函数，可以得出传输线的反射系数，以及支节匹配等参数，本函数可以实现单、双和三支节匹配。,The realization of the impedance function in matlab circle map, by calling the switch () function of transmission line can be drawn of the reflection coefficient, as well as the