Three New Rat-Race Couplers with Defected Microstrip and Ground Structure (DMGS)
Keywords:
Defect on microstrip, defect on ground, DMGS, hybrid ring rat-race couplerAbstract
In this paper, three new types of ratrace ring couplers with defected microstrip and ground structure (DMGS) are presented and one type is fabricated to validate the simulation results. The proposed structures have the advantages of size reduction as well as 3rd harmonic suppression. Embedding the DMGS section increases the slowwave factor (SWF) and as a result the resonant frequency of the coupler decreases, which sets the stage for size reduction. In addition, insertion losses of the 3rd harmonic of the proposed couplers are reduced to 35 dB. After optimizing with genetic algorithm (GA), one type is fabricated. Good agreement between the simulation and measurement results is observed. Simulations are carried out using HFSS 13 and the designed coupler is validated by measurement.
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