Design of 10 dB branch line coupler by using DGS

A new planar 10 dB loose branch line coupler is proposed for application to the 2.5 GHz centre frequency. This proposed coupler is implemented with rectangular ring headed dumbbell shaped Defect Ground Structure (DGS) along with conventional microstrip transmission line. Design of this conventional branch line coupler with DGS provides more design flexibility. Using the DGS, increases the electrical length of microstrip line, provides slow wave characteristics and increases the impedance of the microstrip line. In this paper one required high impedance microstrip line is implemented easily using proposed DGS structure. Finally, the compact microstrip 10 dB loose coupler is designed.