Miniaturized Dual-Band Branch-line Coupler with Folded Stubs

This paper presents a new design of a branch-line coupler using stubs, working on dual band applications. In this design, the conventional line is replaced by a T-shaped line using the designed equations derived from ABCD matrices. To further reduce the size of coupler, the stubs are folded inside and are bent. For this,90° mitered bend are used. The design uses Rogers RO4003 substrate and the frequencies of operation are 0.9 and 2 GHz. It has been designed and simulated on CST Microwave Studio.