An Equivalent Circuit Model for a Dumbbell-Shaped DGS Microstrip Line

Abstract

This paper presents an equivalent circuit model for a dumbbell-shaped defected ground structure (DGS) in a microstrip line. The effects of equivalent circuit elements of a dumbbell-shaped DGS and their magnetic coupling to the host transmission line are modeled as a simple lumped-element circuit. In addition, simple approximate expressions to determine the main circuit parameters for this model are presented. The transfer characteristic calculated by the proposed circuit model is compared with the results of EM simulation and measurement. This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/ by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. ⓒ

A simple method for improving the stopband response for unequal‐length microstrip coupled‐line filters with stubs

“…Because of this, MTM shows the property of negative propagation constant [1]. Metamaterials have found their interesting applications in antenna system, cloaking, filters and in many microwave passive circuits [3][4][5][6]. In recent years, the idea of metamaterial absorber which having advantages of ultrathin thickness with nearly unity absorption, simple manufacturing procedures, etc., over conventional absorbers, has attracted wide interests among researchers.…”

“…Several methods proposed for the enhancement of the stopband of stopband response in microstrip coupled-line filters have shown outstanding performance [2][3][4][5][6][7][8]. For instance, excellent stopband performance is obtained by embedding a defected ground structure (DGS) [2][3][4][5] in ground planes. However, the need of timeconsuming full-wave simulations is inevitable for these groundperturbation techniques, which may complicate the design procedure.…”

“…Since various modern communication services operate in different frequency bands, effective suppression of these responses is crucial, but this suppression must not degrade the performance of the fundamental passband. Several methods proposed for the enhancement of the stopband of stopband response in microstrip coupled‐line filters have shown outstanding performance . For instance, excellent stopband performance is obtained by embedding a defected ground structure (DGS) in ground planes.…”

Discussion and Analysis of Dumbbell Defect-Ground-Structure (DB-DGS) Resonators for Sensing Applications from a Circuit Theory Perspective

“…Therefore, the line present on top of the DB-DGS can magnetically excite the resonant element. Thus, a more realistic circuit model of the DB-DGS-loaded microstrip transmission line is the one depicted in Figure 2a [16,17]. In this model, L c and C c describe the DB-DGS resonator, as indicated before.…”

“…However, it is apparent that the driving mechanism should be the same. Indeed, in previous papers [16,17], a different model of the DB-DGS-loaded microstrip line, which accounts for the magnetic coupling between the host line and the resonant element, has been reported. Actually, the simple model of Figure 1 can be derived from such model by element transformation.…”