Dual-band bandpass filter with rectangular dumbbell shaped defected ground structure / Nik Aswani Nik Ahmad

In this thesis, a design of rectangular dumbbell shaped defected ground structure (DGS) is presented to enhance the response of an existing design of a dual-band bandpass filter topology. The filter design is based on a parallel-coupled lines connected to transmission lines forming a single ring that exhibits a dual-band response with high selectivity with the existence. The filter can be characterized as impedances of the transmission line represented by Zr, even-mode, Zoe and odd mode, Zoo. The variety of size and positions of the DGS were studied with the analysis on the response of the filter. An insertion of a rectangular dumbbell shaped DGS in this topology enhances the response with center frequency given at 2 GHz using Taconic,TRF-45 material. The dimension and position of the dumbbell shape is improved individually, situated at the ground plane. The simulated and measured aftereffects of the DGS insertion are analyzed to validate the concept.