Ultrawide band 180 degree hybrid coupler design

In this study, an ultra-wide bandwidth 180 degree hybrid coupler which performs in 1 – 15 GHz bandwidth design is presented. In the design, multisection coupler design and multisection phase shifter design methods are implemented. In order to realize the proper coupling values, three-layered stripline is used with RT/Duroid 5880 substrate. It is preffered that the top and bottom layer thickness of three-layered stripline structure is 1.525 mm and the middle layer thickness is 0.254 mm. Two different coupler are design in the form of the structure: one of them performs coupling only through substrate and the other performs coupling through substrate and crossover via. For both couplers, it is obtained the simulation and measurement results and their comparisions.