Design of multiband bandstop microstrip filter using SMD capacitor

This work presents the design of multiband bandstop filters (BSFs) based on defected ground structure (DGS) technique. The filters are loaded by surface-mount device (SMD) capacitors for dual and triple stopbands operated at 3.69/7.63 GHz and 3.2/5.56/7.28 GHz, respectively. An additional BSF structure without SMD capacitors operated at 3.77/7.16 GHz is as well designed and fabricated. Due to their satisfactory stopband performances, the proposed filters can be useful for varied communication systems with dual and triple bands rejection for WiMAX/C bands. Keywords: Bandstop filter (BSF), Multiband, Defected ground structure (DGS), Surface-mount device (SMD) capacitor, WiMAX/C bands.