• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.7
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• pp.785-790
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• 2008

In this paper, a new balun is proposed. This proposed balun has a DGS(Defected Ground Structure) pattern on the ground plane. The transmission-line is transformed by microstrip-to-slotline transition. DGS pattern on the ground plane and transition of the lines can be easily made a property of the balun. Resonance frequency of the DGS leads to operating frequency of the balun. Also the transition produces $180^{\circ}$ out-of-phase between two output ports without additional transmission line. In this paper, a new balun with VPDGS(Vertically Periodic Defected Ground Structure) effectively lower the operating frequency. To validate the proposed design method, the new balun is designed, fabricated and measured at 2 GHz.