Frequency-Selective Limiting

In the usual microwave limiter, the presence of one more large signals above a certain threshold level produces a limiting action which can be explained as a change in insertion loss of the limiter so as to maintain a constant output power, regardless of the number of independent signals present. Experimental results of coincidence mode passive ferrite limiters in S band and C band are presented which show that they do not behave in this manner, but rather to a good approximation limit on a frequency-by-frequency or frequency-selective basis. A qualitative explanation of this phenomenon is presented, using the passive parametric limiter as a model.