Abstract: The backscattering cross sections of three kinds of chaff clouds models are computed by the Method of Moment(MM). The results show that multi couple has very little effect on RCS when the average spacing is larger than 2λ. And the cumulative probability function of backscattering cross section with multi couple can be expressed by an exponential distribution just like the condition without multi couple, except for the only difference that the expectation should be modified.

Key words: chaff clouds, r adar cr oss section, method of moment