The generalized foster theorem and network-Q

摘要

This paper proves the generalized Foster theorem, which can be applied to any lossy situation, while the original Foster theorem [1] only applied to reactive termination. Furthermore, the formula of Q with network parameters is described. One example, the quality factor Q of a pass-through resonant cavity, is given here. It is clearly seen that the slope of the reactance function may be negative in a lossy Situation.