Wideband six-port reflectometer design formed by enhanced branch-line couplers

A new wideband six-port reflectometer design concerning operating frequency of 2.5 to 4 GHz is presented in this article. The proposed reflectometer is constructed by using five branch-line couplers, which designed by implementing stub impedances and Defect Ground Structure (DGS). The applied DGS has a shape of rectangular ring headed dumbbell. The design and analysis of the proposed branch line coupler and reflectometer are performed by applying CST Microwave Studio software. The simulation result shows that the scattering parameter performances of branch line coupler and reflectometer have good achievement over 2.5 to 4 GHz, which is enhanced up to 11% of bandwidth compared to the conventional branch line coupler.