Design and validation of low-pass filter using microstrip stub and defected ground structure

In this article, a compact microstrip low-pass filter using conventional elliptical headed dumbbell-shaped defected ground structure (DGS) is presented.The proposed structure with main dimension parameters has been analyzed as a design guide, which can be used to fabricate the filter in future. The H-shape open stub increases the equivalent parallel capacitance to improve the out-band suppression. The proposed LPF shows low cut-off frequency response, low insertion loss, sharp transition, and fairly good rejection in stop band. For the five-array DGS filter, including stubs provides the rejection in stop band from 2.8 GHz to higher frequencies. DGSs have shown increasing potential for implementation in different applications: microwave integrated circuit (MIC), monolithic microwave integrated circuit (MMIC), and radio frequency integrated circuit (RFIC). They provide sharp, distinct electromagnetic band-gap, and high slow wave factor, which lead to smaller size circuits and takes lots of engineering challenges. (C) 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:571573, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27361