Defected Ground Structure Structure Research Articles

Frequency reconfigurable circular microstrip G-slotted antenna with DGS for various wireless applications

Frequency reconfigurable circular microstrip G-slotted antenna with DGS for various wireless applications

Revolutionary Triangular Patch Antenna with Dumbbell-Shaped Defected Ground Structure for 5G at 3.7 GHz: A Disruptive Design Innovation

This research proposes the use of a triangularshaped printed antenna operating at 3.7 GHz as a Defected Ground Structure (DGS) for a 5G communication system. The design of triangular antenna is incorporates with a printed Dumbbell shaped DGS structure in order to reduce the cost of antenna fabrication. The aim is to improve service performance, effectiveness, and quality of 5G communication systems. The proposed antenna has been analyzed and found to have return losses of -28.73 dB at the resonant frequency of 3.73 GHz, and an antenna gain of 3.23 dB. The DGS design is expected to increase the performance and this antenna be a choice for 5G communication systems.

High isolation MIMO antenna for 5G C-band application by using combination of dielectric resonator, electromagnetic bandgap, and defected ground structure

High isolation between massive MIMO antenna elements is one of the important parameters that improves antenna performance, especially for 5G communication applications. In this study, we propose a design to improve isolation between elements to enhance the antenna performance. The proposed solution to improve the performance of massive MIMO antennas is to use a combination of dielectric resonator, electromagnetic bandgap (EBG) and defected ground structure (DGS) techniques at the frequency band 3.5 GHz as the 5G frequency band under 6 GHz. The material used is FR-4 which has a dielectric constant ({varepsilon }_{r}) of 4.3. Simulation results and measurements between antenna elements show an improvement in mutual coupling, widening the bandwidth and increasing the gain of the antenna. The proposed design using the dielectric resonator antenna (DRA) by MIMO 8 × 8 16 port—64 elements and the addition of EBG and DGS structures on the ground plane—has shown to suppress mutual coupling parameter lower than without using DRA-EBG-DGS design by 15 dB, increase bandwidth to 246 MHz, increase gain to 24.7 dB and improve the overall envelope correlation coefficient (ECC) parameter.

Low-cost ELC-UWB fan-shaped antenna using parasitic SRR triplet for ISM band and PCS applications

ABSTRACT This article presents a low-cost, fan-shaped, tri-arm, circular microstrip antenna that is practically loaded with the three split-ring resonators (SRR) and also uses defected ground structure (DGS) to obtain ultra-wideband (UWB) performance. To compensate for the decreased value of gain because of the DGS structure, the antenna is further loaded parasitically with three split-ring resonators (SRR). The introduced metamaterial SRR triplet results in improved impedance matching and 7 dB improvement in reflection coefficient (S11) at the designed frequency. This also leads to improvement in the gain of antenna and a gain of 7.16 dBi has been obtained. The paper reports 10 dB bandwidth from 1.81 GHz to 3.0 GHz which covers applications like Wi-MAX, Wi-Fi, GSM (1.9 GHz), public safety band, Bluetooth, ISM band (2.4–2.5 GHz), 3 G (2.1 GHz), 4 G LTE(2.1–2.5 GHz), WCDMA (1.9, 2.1 GHz) and other PCS applications. The measured values of S11 is lower than −10 dB for the fractional bandwidth more than 48.98% and hence ultra-wideband performance has been achieved. The antenna is novel in the sense it contains three fractal rectangular arms in the basic circular patch. The addition of arms in patch increases the overall electrical length, which results in improvement in overall bandwidth.

Designing 6–18 GHz Microstrip Filters with Removing Unwanted Upper and Lower Band Frequency Responses and with Arbitrary Load Impedance Matching

In this paper, Ultra-Wideband (UWB) filters at 6–18[Formula: see text]GHz are designed that can reduce undesired frequency responses at lower and upper frequency bands to less than [Formula: see text]20[Formula: see text]dB. Arbitrary load impedances are considered in the design of these filters. The structure of these filters is the combination of microstrip band-pass filters and Defected Ground Structures (DGSs) with multiple sections. The optimum circuit dimensions are calculated using a computer code which implements the Least Mean Squares (LMS) optimization method. Two design examples are included to illustrate this method. In these examples, eight-section DGS structures are employed to eliminate the unwanted upper frequency band responses. To ensure the correct performance of the designed filters, they are analyzed using full-wave methods and fabrication and the results of the measurement or full-wave analysis shows good agreement with the results of the computer code and the circuit model simulations.

Miniaturized antenna using DGS and meander structure for dual‐band application

AbstractIn this article, the design of a miniaturized planar antenna using defected ground structure (DGS) and meander line structure for C and X‐band applications is presented. A novel star‐shaped and a rectangle DGS created on the ground plane of lambda/4 fed planar antenna and its effect on the size reduction performance is analyzed. Initially, a simple basic antenna (antenna‐1) operates at 14.9 GHz with a reflection coefficient (S11) of −34.56 dB is designed. To achieve miniaturization of 51.27% and 36.77% an antenna is designed by DGS and meander line structure (antenna‐2), which operates at dual‐band frequencies 7.26 and 9.42 GHz with a reflection coefficient (S11) of −32.91 and −22.84 dB, respectively, is presented. The suggested antenna is fabricated on a 1.6 mm thickness of FR4 Epoxy substrate to achieve a reasonable peak gain and directivity of 3.64 and 5.94 dBi at 7.26 GHz, 3.23 and 5.44 dBi at 9.42 GHz, respectively, is achieved.

System‐based modelling and synthesis of defected ground structure resonators and filters

This paper describes a method for the system modelling and synthesis of defected ground structure (DGS) resonators based on the singularity expansion method (SEM). The analytical expressions of the transfer functions for three types (dumbbell-shaped, C-shaped and meander-shaped) of DGS resonators are formulated. The physical poles of the DGS structures are extracted utilising a pole-energy-based matrix pencil (MP) scheme. Afterwards, the transfer function expressions are utilised to develop an accurate equivalent lumped-element circuit for the three types of DGS resonators. A systematic synthesis method using the generalised transfer function of the resonators is proposed to design a meander-shaped DGS dual-bandpass filter. Good agreement is observed between the transfer function model of the system and the computed frequency domain data of the synthesised DGS filter. The developed procedures of system-based modelling and synthesis are general and can be used systematically to synthesise multipart DGS filter structures.

Design Approach for Efficient Wireless Power Transfer Systems During Lateral Misalignment

This paper methodizes efficiency improvement during lateral misalignment for the wireless power transfer (WPT) system using two coupled semielliptic defected ground structure (DGS) resonators. We design the WPT system using a scaled value of the available mutual coupling between the resonators at perfect alignment. This scaled mutual coupling value enforces over-coupling regime, and the WPT efficiency is lower than the peak one. Then, during lateral misalignment, WPT efficiency improves until it peaks at critical coupling. Next, with further misalignment, the efficiency drops as the system enters loose coupling regime. The proposed method consists of two steps. First, we derive an analytical approach to determine the scaled mutual coupling value for efficiency design during lateral misalignment, and second, we improve the maximum obtainable efficiency by careful designing of the DGS structures’ profile. We verify the proposed method by implementing the WPT system at 300 MHz, which shows a peak efficiency of 80% for a size $D_{o} \times D_{o} = 40 \times 40$ mm2 with a transfer distance $d = D_{o}$ . During misalignment, the efficiency is higher than 50% for a lateral shift up to ±0.75 $D_{o}$ .

Suppression of Mutual Coupling Between Two Microstrip Patch Antennas using a Sophisticated Non-Linear DGS Structure for High Frequency Wave Applications

Purpose – If the two or more than two antennas are present in the antenna array, the mutual coupling between them becomes a critical issue to deal with. At microwave frequency, microstrip design is often used as a transmission line because of its good performance in transferring the energy and microwave signals. Most commonly used microstrip antenna has similar structure as that of the microstrip line. On one side of dielectric substrate layer, is an extremely thin layer of conductor that forms the radiating elements and on bottom side is the ground plane made up of metallic material. Our main motive is to maintain mutual coupling suppressing structure to its simplest form.
 Methodology/approach/design – We therefore use a Defected Ground Structure (DGS), which greatly decreases the mutual coupling between the two antennas, thus enhancing the performance of the antenna array.
 Findings – The introduction of the DGS does not affect the characteristics of antenna array system. The Simulation is done using CST (Computer Simulation Technology) software and the results are tested using Vector Network Analyzer. Both the simulated and measured results are in good agreement. The coupling has been reduced from -22 to -37 dB. The recent boom in wireless industry has led to the demand for the multiband antennas.

DESIGN AND PERFORMANCE ANALYSIS OF UWB CIRCULAR RING ANTENNA WITH DEFECTED GROUND STRUCTURE

A compact circular ring antenna with defected ground structure (DGS) has been design for Ultra-Wide Band (UWB) applications. Initially, a circular patch antenna is design by introducing a rectangular DGS structure. Further, slot has been inserted in circular patch to improve the impedance bandwidth. The proposed design covers the frequency range of 2.4-10.4GHz below -10dB. Proposed antenna has design and fabricated on FR-4 substrate having 1.5mm, 4.3 thickness and dielectric constant, respectively. The performance of the designed antenna is analyzing with optimized dimensions in terms of return loss, VSWR, radiation pattern, gain characteristics, group delay and surface current distributions. Further, performance analysis of the proposed antenna has also been compared with existing suggested antennas in literature with compact in size. The fabricated antenna shows a good result with simulations software.

Compact Triple-Band MIMO Antenna with High Isolation for Handheld Application

A structure, the proposed MIMO antenna is compact in size and designed on FR4 substrate with total dimension of 37 x 43.6 x 6 m3. At first, a single PIFA antenna is presented using U-shaped slots in radiating patch which puts forward the antenna resonant in three frequencies: 2.4GHz, 3.5GHz and 6.3GHz with bandwidth of 8.87%, 18.29.% and 2.53 % respectively for Wi-Fi, Wimax/LTE and Direct Broadcast Satellite DBS of C channel applications. Good reflection coefficient, antenna gain, and radiation pattern characteristics are obtained in the frequency band of interest. Secondly, the paper has put forward another single type of tri-band PIFA which uses double rectangular shape of Defected Ground Structure (DGS) technology. This helps increasing the antenna efficiency at all frequencies as well as enhancing antenna gain of the PIFA. Finally, a MIMO PIFA antenna is constructed by placing two single antennas side by side at close distance of 4 mm. The MIMO antenna also gets high gain and radiation efficiency at all frequencies. To reduce the mutual coupling between antenna elements, a combination of two “slot and variation” structures of DGS is proposed. Moreover, these DGS structures have enhanced MIMO antenna bandwidth at all three bands, especially at 3.5GHz resonant frequency.

Design of a Compact Rectangular Patch Antenna Using Defected Ground Structure

This paper presents the design of low cost compact coaxial fed rectangular patch antennas with the Defected Ground Structure (DGS).The proposed two metamaterial DGS antennas operate at resonating frequencies of 4.7 GHz and 2.4 GHz, and they showed the reduction in size while having considerable performance. A microstrip patch antenna finds its application in WLAN, WiMAX and Wi-Fi in wireless communication services.The performance measures of conventional and DGS antennas had been simulated and analysed in Computer Simulation Technology Microwave Studio (CSTMWS). Prototypes of the coaxial fed rectangular patch antennas operating at 4.7 GHz and 2.4 GHz are fabricated and measured for the experimental validation of the simulation results of the designs. Both the simulation and measurement results showed that the DGS structures improved the performance of the proposed model and the results suggest that DGS reduced the antenna size up to 34.3% for 4.75 GHZ and 80% for the 2.4 GHz.

Improved chipless tag based on multifilters

AbstractIn this study, a novel compact chipless RFID transponder is presented. The coding information is based on spectral signature using three types of multiresonator: spiral, slot, and U‐shaped defected ground structure (DGS). Each resonator can be seen as a band‐stop filter which contributes to a particular resonance frequency. The previous spiral resonator based barcodes have only 1 bit information on each resonator which result in a large quantity of resonators relatively and a long microstrip line. In our design, the slot is cutting on the spiral resonator so more bits can be stored. The combination of slot and spiral resonators together provides an efficient decrease in resonator numbers. The DGS structure takes use of ground plane of the tag which further increases the capacity without expanding the size. The method of using these three types of resonators presents a clear improvement in miniaturizing the transponder which leads to a compact size of the tag. By applying frequency shift coding (FSC) coding technique, a coding density of 0.946 bit/cm2 is achieved. Improvement in two cross‐polarized transmitting and receiving antennas is also considered in the design. Corresponding experiments on realized prototypes are provided to validate the effectiveness of the proposed design.

Design of Compact Bandpass Filters based on Fractal Defected Ground Structure (DGS) Resonators

Modified Minkowski fractal geometry has been found to be attractive for microwave circuit designers because of its high space-filling property. This property will lead to the design of compact circuits; meeting the requirements of the modern communications systems to be with small size. In this paper, the design of a compact microstrip BandPass Filters (BPF) has been proposed based on the modified Minkowski fractal (DGS) resonators. The proposed BPF structure is composed of two coupled resonators etched as fractal DGS structures. Results reveal that as the iteration level of fractal based DGS becomes higher, more compact filter structure will result in. Furthermore, the presented DGS structures with fractalshaped resonators can be adopted to design compact planar BPFs with reasonable performances. The performance curves offered by the resulting filters are characterized by the low loss across the passband and high rejection levels outside it with steep roll-off in both edges of passband. Measured results of a fabricated prototype of a 2nd iteration fractal DGS BPF have shown reasonable agreement with those predicted by simulation. Measured results of a 2nd iteration fractal DGS BPF have shown satisfactory agreement as compared with simulation results. There is a slight shift of the lower edge of the passband response of the transmission characteristics, while the upper edge is s very close. The results have shown that the filter has reasonable performance characteristics with considerable reduction of higher harmonics. The compact size of the proposed filter together with the realized high selectivity will make it suitable for a broad range of the recently available wireless communication services.

A tunable bandstop filter using T shaped DGS and MEMS switches on CPW

In the present work, a band stop filter with tunable resonant frequency and tunable bandwidth is proposed using micro electromechanical (MEMS) switches. The band stop filter is based on defected ground structures (DGS). Tunability of resonant frequency is achieved through two methods for fine and coarse tuning. The various switching states of the filter are represented by equivalent circuit models. Four MEMS series switches are loaded over each of the four branches of a T-shaped DGS structure. The switches are successively actuated to increase the resonant frequency of the filter in narrow steps. A coarser method of tuning the resonant frequency makes use of two switches connected across the gaps of the DGS. In this method, the resonant frequency varies nonlinearly with the height of the switch beam. The bandwidth of the filter is tuned by actuation of MEMS shunt switches, forming a distributed MEMS transmission line (DMTL) in the spacing between the DGS structures. The actuation of the MEMS shunt switches in the DMTL results in a slow wave effect. This increases the effective electrical length between the DGS structures leading to increase in bandwidth.

Harmonic Control by Defected Ground Structure on Microstrip Antenna Array

The objective of this paper is to use Defected Ground Structure (DGS) in microstrip antenna array for controlling higher order harmonics of the fundamental operating frequency for S band (5.2 GHz) application. The soft nature of DGS facilitates improvement in the performance of microstrip antennas. The effect of the position of DGS below the feed location has been presented in the proposed work. In this paper, two dumbbells shaped defected ground structure has been integrated below the feed location with the detailed study of its dimension. Properly placed DGS just below the feed line totally eliminates higher order modes without significant effects on fundamental resonance frequency and its radiation pattern. DGS below the feed line represents the stop band characteristics at a certain frequency and that has been adapted to reduce the higher order harmonics. A prototype of the antenna was fabricated with the RT-DUROID substrate. Experimental validation of technique is carried out and measured results were found to be comparable with simulated results. The plots of return loss, radiation pattern with and without dumbbell shaped DGS structure are given in details.

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%.

Dual-Frequency Two-Element Antenna Array with Suppressed Mutual Coupling

An efficient technique utilizing the defected ground structure (DGS) to suppress the mutual coupling effect of a dual-frequency microstrip antenna array is studied. The proposed dual-frequency DGS beneath two patches includes two circular split ring slots, each of which corresponds to one resonant frequency of the patches. The characteristic of the compact DGS is theoretically and experimentally investigated. The prototypes of the patches arrays with and without the proposed DGS are fabricated. Both the simulated and measured results show that the mutual coupling between array elements has been obviously reduced at the two operating frequency bands with the implementation of the proposed DGS structure.

Design of a High-Power Superconducting Filter With Novel DGS Structures

A novel defected ground structure (DGS) resonator with improved power handling capability is proposed in this paper. The current density distribution of the DGS resonator is simulated and compared with that of the complete ground structure (CGS) resonator. Simulation shows that the maximum current density of the DGS resonator is lower than that of the CGS resonator. Two four-pole bandpass high-temperature superconducting filters centered at 2.9 GHz with a fractional bandwidth of nearly 1.5% are designed and fabricated using the DGS and CGS resonators, respectively. The measured maximum handling power is 37.3 dBm for the DGS filter at 77 K, which is higher than that of 34.1 dBm for the CGS filter.

Design and analysis of a structure-based microstrip bandpass filter

A structure-based microstrip passband filter with the center frequency of 2.6 GHz was put forward by using double-mode resonator based on defected ground structure (DGS) technology. A double-mode coupling resonator combined with DGS structure was used to achieve the resonance frequency and the filter size. CST microwave studio was used to optimize the attenuation performance to get the filter parameters. A structure-based passband filter was fabricated. Simulation is consistent with the measurement. Performance shows that the proposed filter could be suitable for the time division-long term devolution (TD-LTE) microwave systems at 2.6 GHz.