In this paper, a 1:11 unequal microstrip Wilkinson power divider (WPD) is presented. Power division is a necessary function in most of the wireless/wireline communication systems. To design 1:11 WPD using an easy-to-fabricate microstrip technology, microstrip line having a very high characteristic impedance (Zc) value of 315 Ω is needed. Realization of this value is impractical because too thin line is required. Defected ground structure (DGS) provides the hosting microstrip line with high inductance and modest capacitance values simultaneously. As a result, very high impedance could be implemented using practical lines. Novel analytical calculation method is developed to compute Zc of microstrip line loaded with DGS. It is found that circular-patterned DGS could be used to realize the required microstrip line. The designed WPD is fabricated and measured at centre frequency (fc) equals 1 GHz. The measurements of insertion and reflection losses of the fabricated circuit as well as the isolation between the output ports are in a good agreement with the simulated responses of the designed circuit.