A COMPACT ULTRA-WIDEBAND BAND-PASS FILTER WITH DEFECTED GROUND STRUCTURE

In this article, a compact ultra-wideband (UWB) band-pass filter (BPF) with improved upper-stopband is presented. In this design, a novel multiple-made resonator (MMR) with two symmetrical loading stubs and three dumbbell-shaped defected ground structures (DGS) on the back of the filter improve the harmonic-suppression characteristic of conventional BPF. Combining these two structures, a new UWB BPF is fabricated and measured. Measured results show that the proposed BPF has wide bandwidth from 3.0 to 10.7 GHz and the insertion loss of the BPF is less than 1.0 dB in this bond. A wide stop-band bandwidth with 20 dB attenuation from 12 GHz lip to 20 GHz is achieved. (C) 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 979-981 2009: Published online in Wiley InterScience DOI 10.1002/mop.24234