This article presents new and accurate synthesis formulas for the microcoplanar stripline (MCS). The synthesis formulas tire obtained by means of a differential evolution algorithm, and are useful to microwave engineers for accurately calculating the physical dimensions of MCS. The average percentage error is calculated to be 0.9% for 2254 MCS samples having different electrical parameters and physical dimensions, as compared with the results of the quasistatic analysis. (c) 2008 Wiley Periodicals. Inc.