在近代微波测量技术中,“活动短路法”获得了极为广泛的应用,其中所谓“S曲线法”或“正切法”应用得更为普遍.这是基于四端网络阻抗变换原理的一种方法.实质上,它是由移动终端“活动短路器”而测量四端网络前面传输线中驻波节点的位移,然后作出这二个位移之间的关系曲线,从而在图上求得曲线(即S曲线)波动的幅值,最后由关系式算出此被测四端网络的固有反射系数.理论分析表明,由四端网络引起的不匹配造成的反射,其对应的驻波系数ρ与此曲线 In modern microwave measurement techniques, the “active short-circuit method” has gained a very wide range of applications, the so-called “S-curve method” or “tangent method” is more common. This is based on four-terminal network impedance transformation principle of a method In essence, it measures the displacement of the standing wave node in the transmission line in front of the four-terminal network by the mobile terminal “movable short-circuit device”, and then makes the relation curve between these two displacements to obtain the curve (ie, S Curve), and finally calculate the inherent reflection coefficient of this four-end network by the relations.Theoretical analysis shows that the reflection caused by the mismatch caused by the four-end network, the corresponding standing wave coefficient ρ and the curve