Periodic Defected Ground Structure Research Articles

Design and simulation of continuous tuning band stop filter by2-D periodic defected ground structure

In this paper, the design and simulation of a continuous tuning bandstopfilter (BSF) is done by using two-dimensional (2-D) periodic DGS for the coplanar waveguide (CPW) transmission line. The proposed BSF filter structure has DGS cells on the ground plane of the CPW transmission line. This structure can easily be designed for another frequency band by changing the number of periodic DGS unit cells. This BSF has a fixed bandwidth of 8.2 GHz over a wide range of frequencies (16–26) GHz.The tunability of the BSF is achieved by moving plates, which are kept above the substrate of the CPW. The size of these plates is the same as the size of the DGS cell. The tunability of the BSF is observed while changing the distance between the metal plates and substrate in the up position. In the down position the metal plates are covered by the DGS cells, then the filter act as a normal transmission line. The extraction of the equivalent circuit model parameters has also been derived. The electromagnetic (EM) and equivalent model simulations are done with the HFSS and ADS tools, both these simulations have a good agreement with each other. From this, the proposed BSF can be used for satellite and radar communication in K band frequency range.

Performance Enhancement of an Inset Fed Circular Microstrip Patch Antenna Using Periodic Defected Ground Structure and EBG Superstrates for Applications in the Millimeter Wave Band

The aim of this work is to enhance the intrinsic performance of a circular microstrip patch antenna, using two optimization techniques, widely used nowadays in antenna field, due to their promising features of improving gain, directivity, and return loss. The first one consists on incorporating a periodic DGS (Defected ground Structure) in the ground plane of the proposed antenna , while the second method involve adding double EBG dielectric superstrate atop of the patch. The proposed antenna is designed to operate in the millimeter wave band, more exactly at 30GHz, formulated using cavity model, and its behavior has been explained using an EM-simulator, based on finite element method: HFSSv15(High Frequency Structure Simulator).

Microstrip antenna array mutual coupling suppression using coupled polarisation transformer

This study presents a periodic defected ground structure (PDGS) to suppress the mutual coupling (MC) between coplanar antenna elements in a multiple-input and multiple-output (MIMO) communication system. The proposed PDGS consists of three defected ground structure units. They are etched away from the ground plane between antenna elements. The coupled polarisation transformer characteristic of the proposed PDGS is utilised to increase the antenna elements isolation. The increased coupled vertical linear polarisation component and decreased coupled horizontal linear polarisation component contribute to reduce the MC between antenna elements. By using this method, the authors achieve low MC level and better MIMO corresponding capacity. This method has little influence on the far-filed main radiation properties of the antenna elements.

S‐shaped periodic defected ground structures to reduce microstrip antenna array mutual coupling

A novel S-shaped periodic defected ground structure (PDGS) is proposed to reduce mutual coupling between antenna elements. Coplanar placed antenna elements work at the same frequency band with centre frequency 2.57 GHz. Centre-to-centre distance between the antenna elements is 50 mm which is ~0.43λ. The PDGS is three S-shaped defected ground structure units placed between microstrip antenna elements. By using the proposed PDGS, more than 40 dB mutual coupling reduction between microstrip antenna elements is achieved.

A broad stopband common-mode suppression defected ground structure filter with complementary structure

A low-cost defected ground structure (DGS) wideband stopband filter adopting complementary structure is proposed, which is designed for common-mode noise suppression in high-speed differential signals. The filter is etched below the low cost FR4 printed circuit board. To avoid stimulating the common-mode noise, the DGS cells on ground planes are kept symmetrical to the central line of the two differential signal lines. Both sides of the filter adopt a symmetric cup-shape DGS structure and the middle of the filter adopts a symmetric umbrella-type structure. All of the DGS structures are complementary, which makes the filter compact and miniaturized. What is more, because the spaces among the three DGS are closer, there exist the mutual inductances among them, which are utilized to achieve a wide stopband filter. The simulated result demonstrates the proposed filter has a wideband bandwidth of 6.8 GHz over 20 dB. In order to analyze the effect of compact structure of the filter, a filter having the same DGS patterns but large spaces among them is compared with it. The simulated result demonstrates that the stopband bandwidth of the compared filter has a wideband bandwidth of 4.4 GHz over 20 dB, of which the bandwidth is about 2.4 GHz less than that of the proposed filter. It is obvious that there exists a mutual inductance in the compact DGS structure common-mode filter, which plays an important role in broadening the bandwidth of the proposed filter. In order to facilitate analysis, an equivalent model of LC circuit is also given. The equivalent parameters of LC can be deduced from the definition of 3 dB cut-off frequency and resonant frequency, of which the values can be obtained by the HFSS simulation. The simulated and measured results show that the differential signal under the DGS filter is nearly intact, and the common-mode noise can be reduced over 20 dB from 4.6 GHz to 11.4 GHz and over 15 dB from 4.3 GHz to 12 GHz, while the area of the filter is only 10 mm by 10 mm. Compared with the periodic DGS at the same suppression depth of common-mode noise over 20 dB, the method has the advantages that surface area is reduced to no more than 30%, and the stopband width is increased by over 50%.

Analyzing Uncertainties of Rectangular Periodic Defected Ground Structure Characteristics

The defected ground structure (DGS) is one such technique which where intentionally modified to enhance the performance of the ground plane metal of a microstrip circuit. Importantly, in microwave application, the DGS plays an important role in analyzing the effect of surface and leaky waves. During the time of experimental analysis, the surface and leaky waves are affected by the propagation uncertainties. Hence, the performance of microstrip circuit is also affected. So, proper mathematical model is needed for analyzing the propagation uncertainty of DGS and to improve the performance. In this paper, the curve fitting mathematical model is proposed for analyzing the propagation uncertainty. In the proposed model, the bi-segmentation process is applied to the experimental characteristics. The proposed curve fitting model is implemented and the Rectangular Periodic defected ground structure propagation uncertainties are analyzed.

Radiation Characteristics of a Microstrip Patch Antenna over a Periodic Defected Ground Structure Substrate

In this article, the radiation characteristics of the microstrip patch antenna with periodic defected ground structures have been studied. These structures are realized by etching off defected patterns from the ground plane of planar circuits and antennas. Results indicate that a periodic defected ground structure has good effect on reducing the patch resonant length without decreasing the impedance bandwidth.

수직 결함 기저면 구조를 이용한 새로운 발룬 구조 연구

수직 결함 기저면 구조를 이용한 새로운 발룬 구조 연구

PROPAGATION CHARACTERISTICS OF MICROSTRIP LINES (MTLs) WITH DEFECTED GROUND STRUCTURE SLOTS: THEORY AND APPLICATION

Propagation characteristics, including scattering, dispersion, and loss modeling, of some microstrip lines (MTLs) with defected ground structure (DGS) slots were investigated in this paper. A simple approach was firstly introduced to calculate the slow-wave factors (SWF) of these MTLs with DGS. Based on the above-mentioned theory, a meander MTL structure with periodic DGS slots was proposed and analyzed. The improved SWF and characteristic impedances have been demonstrated, while the bandgap performances have been proved by experimental results. Further, a type of nonuniform DGS slots, which are composed of dual-periodic photonic bandgap structures, was applied to reduce the second-order harmonics and improve the output power of a Ku-band voltage-controlled oscillator. Measurements showed that the second-order harmonics are suppressed by more than - 20 dB and the output power is improved by 3–5%.

A MEMS Reconfigurable DGS Resonator for K-Band Applications

A MEMS reconfigurable defected-ground-structure (DGS) resonator using two-dimensional (2-D) periodic DGS for coplanar waveguide (CPW) transmission line and RF MEMS series-resistive switches is proposed. The introduced MEMS reconfigurable DGS resonator has approximately a fixed bandwidth of 8.1 GHz over a wideband frequency range (K-band). The proposed structure can be designed easily for other frequency bands by changing the number of unit-cells of the 2-D PDGS. A cascaded two parallel-resonance circuit model for the MEMS reconfigurable DGS resonator has been introduced as well. The equivalent circuit parameters extraction methods have also been derived. Simulations based on the proposed circuit model are in a very good agreement with the electromagnetic (EM) simulations, which suggests that the MEMS reconfigurable DGS resonator is an inductive controlled reconfigured structure. The structure is designed in CPW environment on a high-resistivity silicon substrate. It is therefore suitable for monolithic integration with standard IC process

An improved 1D periodic defected ground structure for microstrip line

A novel one-dimensional (1-D) periodic defected ground structure (DGS) for microstrip line is presented in this letter. Different from the periodic DGS with uniform square-patterned defects, the improved periodic DGS has a compensated microstrip line and the dimensions of the square defects are nonuniform and varied proportionally to the relative amplitudes distribution of the exponential function e/sup 1/n/ (n denotes the positive integer). A uniform periodic DGS circuit and two improved periodic DGS circuits are designed, fabricated, and measured. Measurements show that the latter exhibit more excellent performances by suppressing ripples and enlarging stopband bandwidth.

A vertically periodic defected ground structure and its application in reducing the size of microwave circuits

The microstrip and coplanar waveguide transmission lines combined by a vertically periodic defected ground structure (VPDGS) are proposed. The slow-wave effect, equivalent circuit, and the performances are shown. As an application example, VPDGS is adopted in the matching networks of an amplifier for size-reduction. Two series microstrip lines in input and output matching networks of the amplifier are reduced to 38.5% and 44.4% of the original lengths, respectively, due to the increased slow-wave effects, while the amplifier performances are preserved.

Vertically periodic defected ground structure for planar transmission lines

A vertically periodic defected ground structure (VPDGS) for microstrip is described. VPDGS has additional vertical periodicity of defects plus the conventional horizontal periodicity on the ground plane. The slow-wave factors and the predicted and measured performances are presented.

A novel 1-D periodic defected ground structure for planar circuits

A new one-dimensional (1-D) defected ground unit lattice is proposed in order to improve the effective inductance. Increasing the effective inductance makes it easy to control the cutoff frequency characteristics. The proposed periodic defected ground structure (DGS) provides the excellent cutoff and stopband characteristics. In order to show the improved the effective inductance, three DGS circuits were fabricated with identical periodic and different dimensions. Measurements on the fabricated DGS circuits show that the cutoff and stopband center frequency characteristics depend on the physical dimension of the proposed DGS unit lattice,.

Novel Two‐Dimensional (2‐D) Defected Ground Array for Planar Circuits

This paper presents a novel two‐dimensional (2‐D) defected ground array (DGA) for planar circuits, which has horizontal and vertical periodicities of defect structure. The defected unit cell of DGA is composed of a Sierpinski carpet structure to improve the effective inductance. Measurements show that the proposed DGA provides steeper cutoff characteristics, lower cutoff frequency, and higher slow‐wave factors than the conventional periodic defected ground structure in the same occupied surface.