Defected Ground Structure, (a) 1-D DGS [5] (b) 2-D DGS[34] 

Contexts in source publication

Context 1

... components such as filters, couplers, antennas etc., in the microstrip technology, are used in high performance aircraft, spacecraft, satellite and missiles where size, weight, cost, performance, ease of installation, and aerody- namic profile are constraints. Presently there are many other government and commercial applications, such as mobile radio and wireless communications, microwave communication and millimeter wave communication. In its most basic form, the microstrip technology consists of a microstrip transmission line made of conducting material on one side of a dielectric substrate which has a ground plane on the other side. There are two different type of generic structures used for the design of the compact and high performance microwave components, named as defected ground structure (DGS) and the Elecromagnetic band gap (EBG) structures generally known as the photonic band gap structures (PBG) [1]. These structures have been attractive to obtain the function of unwanted frequency rejection and circuit size reduction. DGS cells have inherently resonant property; many of them have applied to filter circuits. However, it is difficult to use a PBG structure (periodic structure) for the design of the microwave or millimeter wave components due to the difficulties of the modeling. Another difficulty in using the PBG circuit is caused by the radiation from the periodic etched defects. Recently a defected ground structure (DGS) have been introduced, DGS is realized by etching off a simple shape in the ground plane, depending on the shape and dimensions of the defect, the shielded current distribution in the ground plane is disturbed, resulting a controlled excitation and propagation of the electromagnetic waves through the substrate layer. The shape of the defect may be changed from the simple shape to the complicated shape for the better performance. Different shapes of DGS structures, such as rectangular [2, 3], square [4], circular [5, 6], dumbbell [7 – 12], spiral [13], L- shaped [14], concentric ring [15], U-shaped and V-shaped [16 – 18], hairpin DGS [19 – 20], hexagonal DGS [21], cross shaped DGS [22] and combined structures [23 – 24] have been appeared in the literature. These structures are also used in periodic form [25 – 26]. DGS have advantages in the area of microwave filter design [2, 3, 6, 7, 9], power amplifiers [27 – 28], dividers [29, 32], microwave oscillators [8], couplers [30], transmission lines [31], combiners [32] and in microstrip antennas [43 – 44]. The defect in the ground plane of the planar transmission lines such as microstrip, Coplanar etc., disturbs the shield current distribution and also changes the characteristics of the transmission line e. g. Capacitance and the Inductance. The photonic bandgap structure is a periodic structure etched in the ground plane. The difference between the PBG and DGS is shown in the table (1). The PBG modifies the properties of the microstrip line such as characteristic impedance and propagation constant. Defected Ground Structure (DGS) is an etched lattice shape (slot), which locates on the ground plane. It is motivated by a study of PBG to change guided wave properties. DGS makes one or a few of PGB etched ground elements in the ground plane .The shape of slot is modified from a simple hole to a more complicated shape. The DGS structure may be found in both one-dimensional [26] and two dimensional forms. [5, 34], as shown in Fig. 1. A unit DGS (dumbbell) section is created in the ground plane as shown in the Fig. 1. The DGS consists of the two rectangular areas and one connecting slot in the ground plane [11, 12] as shown in Fig. 2. The DGS with the microstrip line employs an intentional defect on the ground and it provides band rejection characteristic from the resonance property. The cutoff frequency of the DGS is mainly dependent to the etched square area in ground plane. There is an attenuation pole location, which is due to the etched gap distance. An attenuation pole can be generated by combination of the inductance and capacitance elements. The capacitance factor is needed to explain the frequency characteristic of the DGS section. The etched gap area, which is placed under a conductor line, provides the parallel capacitance with effective line inductance. Thus, the proposed DGS section is fully described by two parameters: the etched lattice dimension and the gap distance. The inductance and capacitance are given as ...

Context 2

... components such as filters, couplers, antennas etc., in the microstrip technology, are used in high performance aircraft, spacecraft, satellite and missiles where size, weight, cost, performance, ease of installation, and aerody- namic profile are constraints. Presently there are many other government and commercial applications, such as mobile radio and wireless communications, microwave communication and millimeter wave communication. In its most basic form, the microstrip technology consists of a microstrip transmission line made of conducting material on one side of a dielectric substrate which has a ground plane on the other side. There are two different type of generic structures used for the design of the compact and high performance microwave components, named as defected ground structure (DGS) and the Elecromagnetic band gap (EBG) structures generally known as the photonic band gap structures (PBG) [1]. These structures have been attractive to obtain the function of unwanted frequency rejection and circuit size reduction. DGS cells have inherently resonant property; many of them have applied to filter circuits. However, it is difficult to use a PBG structure (periodic structure) for the design of the microwave or millimeter wave components due to the difficulties of the modeling. Another difficulty in using the PBG circuit is caused by the radiation from the periodic etched defects. Recently a defected ground structure (DGS) have been introduced, DGS is realized by etching off a simple shape in the ground plane, depending on the shape and dimensions of the defect, the shielded current distribution in the ground plane is disturbed, resulting a controlled excitation and propagation of the electromagnetic waves through the substrate layer. The shape of the defect may be changed from the simple shape to the complicated shape for the better performance. Different shapes of DGS structures, such as rectangular [2, 3], square [4], circular [5, 6], dumbbell [7 – 12], spiral [13], L- shaped [14], concentric ring [15], U-shaped and V-shaped [16 – 18], hairpin DGS [19 – 20], hexagonal DGS [21], cross shaped DGS [22] and combined structures [23 – 24] have been appeared in the literature. These structures are also used in periodic form [25 – 26]. DGS have advantages in the area of microwave filter design [2, 3, 6, 7, 9], power amplifiers [27 – 28], dividers [29, 32], microwave oscillators [8], couplers [30], transmission lines [31], combiners [32] and in microstrip antennas [43 – 44]. The defect in the ground plane of the planar transmission lines such as microstrip, Coplanar etc., disturbs the shield current distribution and also changes the characteristics of the transmission line e. g. Capacitance and the Inductance. The photonic bandgap structure is a periodic structure etched in the ground plane. The difference between the PBG and DGS is shown in the table (1). The PBG modifies the properties of the microstrip line such as characteristic impedance and propagation constant. Defected Ground Structure (DGS) is an etched lattice shape (slot), which locates on the ground plane. It is motivated by a study of PBG to change guided wave properties. DGS makes one or a few of PGB etched ground elements in the ground plane .The shape of slot is modified from a simple hole to a more complicated shape. The DGS structure may be found in both one-dimensional [26] and two dimensional forms. [5, 34], as shown in Fig. 1. A unit DGS (dumbbell) section is created in the ground plane as shown in the Fig. 1. The DGS consists of the two rectangular areas and one connecting slot in the ground plane [11, 12] as shown in Fig. 2. The DGS with the microstrip line employs an intentional defect on the ground and it provides band rejection characteristic from the resonance property. The cutoff frequency of the DGS is mainly dependent to the etched square area in ground plane. There is an attenuation pole location, which is due to the etched gap distance. An attenuation pole can be generated by combination of the inductance and capacitance elements. The capacitance factor is needed to explain the frequency characteristic of the DGS section. The etched gap area, which is placed under a conductor line, provides the parallel capacitance with effective line inductance. Thus, the proposed DGS section is fully described by two parameters: the etched lattice dimension and the gap distance. The inductance and capacitance are given as ...