A miniaturized rat-race coupler operating at a frequency of 5.8 GHz encompassing harmonic suppressions is proposed. In order to reduce the overall size and to improve the performance of the coupler, the quarter wavelength transmission lines are replaced by their equivalent stub loaded lines. The electrical length corresponding to the minimum harmonics that miniaturize the rat-race coupler are compared. A comparative analysis of area of the coupler with different electrical lengths is carried out using AWR Design Environment. © 2017 IEEE.