The paper presents a method for the computation of the radar cross sec
tion of microstrip patches. The approach is based on a combination of
ideas derived from the mixed potential integral equation formulation f
or microstrip antennas, fast convolution algorithms and the biconjugat
e gradient iterative method. All operations are kept at a vector level
and this renders the method capable of handling a large number of unk
nowns. Numerical results for a rectangular and a circular patch have b
een compared with measured results available in literature and a good
agreement has been observed. Advantages and limitations are discussed.