Abstract
Abstract
This paper introduces an innovative band stop filter specifically designed to reject a sub-6GHz band within the 5 G spectrum. Fabricated on an FR4 substrate with a relative permittivity of 4.4, the filter incorporates a defected ground structure (DGS) and features very compact dimensions of 19 mm × 11 mm × 0.8 mm. The filter design is performed using the High Frequency Structure Simulator (HFSS). Besides, the filter’s equivalent circuit is modeled using the ANSYS circuit editor. A parametric study has been conducted to identify the optimal parameters for the filter’s form and size. The proposed filter exhibits a rejected band of 1.42 GHz, spanning from 2.3 GHz to 3.72 GHz, with a center frequency of 3.18 GHz. Within the rejected band, the S21 value is less than −21.36, and the stop band fractional bandwidth (FBW) is 44.65%. Additionally, the filter demonstrates a negative group delay (NGD) characteristic in the frequency range of 2.97 GHz to 3.35 GHz, with a measured NGD time of −0.42 ns, and a quality factor equal to 2.24. These results underscore the filter’s suitability for applications utilizing frequencies below 2 GHz and above 3 GHz, ensuring efficient functionality.