The letter reports the analysis of the reduced-size planar microstrip Wilkinson power divider which uses miniaturized microstrip line instead of conventional quarter wavelength transmission line. The full design formulae of the miniaturized Wilkinson power divider with arbitrary power ratio is first proposed.3dB one-stage and two-stage miniaturized Wilkinson power divider are designed according to the formulae. The ADS EM simulation results of the one-stage miniaturized Wilkinson power divider when the smaller electrical angle is 45 degrees show its reflection coefficient20dB and the transmission loss20dB and the transmission loss
