Design of 1:3 unequal Wilkinson power divider with defected ground structure

A rectangular-shaped defected ground structure (DGS) is introduced and applied to design a 1:3 unequal Wilkinson power divider at 2GHz. The rectangular-shaped DGS pattern can greatly increase the equivalent inductance and decrease the equivalent capacitance at the same time. Higher impedance of the microstrip line with the DGS than that of conventional one can be realized. It is more convenient for the simulated model construction and fabrication by adopting the rectangular-shaped DGS pattern. By employing the DGS to the 1:3 unequal Wilkinson power divider, a 132Ω microstrip line with the DGS is 355% the width of the conventional one and the quarter wavelength ratio has been reduced to 85.5%. From 1.5GHz to 2GHz, the measured power dividing ratio is exactly 1:3 with excellent matching and isolation.