• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.10
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• pp.1044-1051
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• 2003

In this paper, a compact planar microwave duplexer on the high dielectric substrate is presented. As the Ba(Mg$\sub$1/3/Ta$\sub$2/3/)O$_3$(BMT) has good dielectric performances with a high dielectric constant of $\varepsilon$$\sub$r/=23, it is suitable to apply to a printed circuit board fur reducing its circuit size. The BMT substrate is fabricated by using a tape casting fabrication process, and circuit patterns are screen-printed on it by suing silver paste. The open-loop ring type duplexer is designed and implemented on the BMT substrate, and it achieves the smaller size by 80% than one on a commercial substrate($\varepsilon$$\sub$r/=6.15) without degenerating its performance. Therefore the proposed BMT substrate has provided the miniaturization of the duplexer, moreover it can make a contribution towards reducing the size of microwave passive circuits.