A Wide Stop-Band Miniaturized Branch-Line Hybrid Coupler

摘要

In this paper, a novel miniaturized wide stop-band branch-line coupler operating at 2.5 GHz is presented. Two different structures, by combination of a microstrip resonant cell with T-shaped stubs, are formed and hence embedded as horizontal and vertical branches of the hybrid coupler. The ultimate structure of the coupler offers 52% of miniaturization efficiency as compared with its conventional counterpart. The performance of the coupler is verified by measurements in a very good agreement with simulation results and moreover it has been revealed that the coupler is capable to broadly suppress harmonics of the operating frequency from third to seventh, corresponding to a stop-band of 6-18 GHz.