Abstract: A full wave analysis method,named the asymptotic extraction technique,is proposed,which is current,efficient and precise.The theoretical deriving of the method is skillfully completed by a kind of computer assistant method.The method overcomes many difficulties of traditional theoretical deriving of the asymptotic extraction technique and the trouble dealing with complex math-function,so that the process of theoretical deriving is simplified.Compared with the direct integral method,the method can save much time for computing mutual impedance matrix.By using this method,the impedance and radiation pattern of a microstrip line antenna are computed,the result is consistent with those from reference 1 and the result of HFSS.