Defected Ground Structure Slot Research Articles

A Method of Reducing Coupling between PIFAs Using Cross Slot Defected Ground Structure

A Method of Reducing Coupling between PIFAs Using Cross Slot Defected Ground Structure

Mrs HYBRID MUTUAL COUPLING REDUCTION TECHNIQUES IN MULTIPLE INPUT AND MULTIPLE OUTPUT ANTENNA FOR X-BAND APPLICATIONS

In recent years, Multiple Input and Multiple Output antennas (MIMO) used for high-bandwidth communications where it's important to not have interference from microwave or RF systems. The MIMO antenna offers good matching with stable gain and desired radiation patterns but it suffers on mutual coupling effects. The spacing between antenna elements is less than half the wavelength, and then mutual coupling effects are more. This paper provides a review on different mutual coupling reduction techniques in MIMO antenna. In this letter, a hybrid mutual coupling reduction technique such as substrate integrated waveguide (SIW) and defected ground structure (DGS) in MIMO antennas for X-band applications. The developed MIMO antenna has dimensions as 25 x 36 mm over a FR4 1.6 mm substrate. The MIMO antenna has formed by combining two fractal-shaped structures. Here, the antenna element spacing is taken as minimum of 5.62mm. To reduce the mutual coupling effect and enhance gain, hybrid techniques are used. By adding 24 hollow cylindrical SIW is placed in between a MIMO element and six rectangular DGS slots placed at the bottom of the antenna for reducing the mutual coupling and enhance the gain. The proposed antenna operates at resonating frequencies of 10.04 GHz, 11.14 GHz, and 11.69 GHz for measurement. The mutual coupling or isolation loss was observed around <-25 dB. The envelope correlation coefficient (ECC) and diversity gain (DG) of the proposed antenna are 0.0016 and >9 dB, respectively. The gain observed for the proposed design is 5.2 dB. The Ansys high-frequency structure simulator (HFSS) tool is used for antenna simulation.

High gain compact wearable antenna for IoT applications

In this paper, the design of a Defected Ground Structure (DGS)-based microstrip patch antenna tailored for sub-6 GHz 5G applications is reported. The proposed patch antenna is crafted using Jeans textile material. By integrating DGS into the traditional patch antenna design, we achieve a significant reduction in size while simultaneously enhancing the antenna’s performance. The antenna features a rectangular patch shape and is powered through a 50-ohm microstrip feed line. Boasting a compact size of 35.6 × 42.6 × 1.6 mm³, the antenna’s performance is further improved by incorporating DGS and etching slots on the patch. The expertly designed antenna yields a 34.87 dB return loss and a gain of 10.9 dB at a frequency of 3.5 GHz. The fabricated antenna demonstrates a robust impedance bandwidth within the range of 3.41–3.606 GHz. Consequently, the proposed antenna is well-suited for applications in WiMAX and IoT technologies.

Defected ground structure based compact UWB dielectric resonator antennas with enhanced bandwidth

Abstract This article introduces two new compact ultra-wide band (UWB) rectangular dielectric resonator antennas (RDRAs) with enhanced bandwidth (BW), gain, and directivity. The RDRAs are designed at 10 GHz resonant frequency. The proposed RDRAs are compactly designed using resonating dielectric material (RDM) of Alumina_96 pct (ε r = 9.4, tanδ = 0.006) with overall dimensions of 30 × 20 × 4.6 mm3. The RDMs are mounted on FR4 substrate (ε r = 4.4, tanδ = 0.02) with defected ground structure (DGS). The DGS are comprised of rectangular and circular ring slots on it. These compact DGS-RDRAs provides enhanced BW. Prototypes of the two suggested RDRAs are fabricated. The fabricated RDRAs are validated by experimental set-ups. The RDRA with rectangular-ring slot DGS provides impedance BW (S 11 < −10 dB) of 33.97 % (8.6658–12.071 GHz). The impedance BW of the other RDRA is 27.97 % (9.08–11.869 GHz). The rectangular-ring slotted RDRA offers radiation efficiency and peak realized gain of 86.4 % and 6.27 dBi, respectively within the band of operating frequencies. The radiation efficiency and realised gain of circular-ring slotted RDRA are 86.18 % and 5.9 dBi, respectively. Good agreements are achieved in between the simulated results and measured results. The results are compared with some recently developed antennas available in literature. The comparison shows that the proposed RDRAs can be suitable candidate for various X-band applications such as satellite downlinks, synthetic aperture radar, weather monitoring by military and some government organizations.

High isolated Psi-Shaped 4x4 MIMO UWB antenna for RF energy harvesting applications

A 4x4 Ultra Wide Band Multi Input Multi Output antenna with Ψ (Psi) patch on an elliptical slot defected ground structure designed to be in control of Characteristic Mode Theory Analysis. Utilizing the design of the Ψ-shaped antenna offers good isolation of beneath − 20 dB in the full UWB frequency (3.1 GHz to10.6 GHz). The antenna planned on FR4 with thickness of 1.6 mm, dielectric strength of 4.4 and loss tangent value of 0.02. This antenna compromises worthy impedance bandwidth as of 3.10 GHz to 12.00 GHz through with better isolation. This designing furnishes radiation efficiency of 92%, 115% of bandwidth; and maximum peak gain of 6.50 dBi. The diversity features of DG, ECC, CCL and MEG are 9.998, 0.012, 0.25 bits/s/Hz and − 3.2 dB correspondingly. This antenna stands adequate for RF Energy Harvesting Applications.

Defected Ground Structure Multiple Input-Output Antenna For Wireless Applications

In this paper, the investigation of a novel compact 2 × 2, 2 × 1, and 1 × 1 Ultra-Wide Band (UWB) based Multiple-Input Multiple-Output (MIMO) antenna with Defected Ground Structure (DGS) is employed. The proposed Electromagnetic Radiation Structures (ERS) is composed of multiple radiating elements. These MIMO antennas are designed and analyzed with and without DGS. The feeding is introduced by a microstrip-fed line to significantly moderate the radiating structure’s overall size, which is 60 × 40 × 1 mm. The high directivity and divergence characteristics are attained by introducing the microstrip-fed lines perpendicular to each other. And the projected MIMO antenna structures are compared with others by using parameters like Return Loss (RL), Voltage Standing Wave Ratio (VSWR), Radiation Pattern (RP), radiation efficiency, and directivity. The same MIMO set-up is redesigned with DGS, and the resultant parameters are compared. Finally, the Multiple Input and Multiple Output Radiating Structures with and without DGS are compared for result considerations like RL, VSWR, RP, radiation efficiency, and directivity. This projected antenna displays an omnidirectional RP with moderate gain, which is highly recommended for human healthcare applications. By introducing the defected ground structure in bottom layer the lower cut-off frequencies of 2.3, 4.5 and 6.0 GHz are achieved with few biological effects on radio propagation in human body communications. The proposed design covers numerous well-known wireless standards, along with dual-function DGS slots, and it can be easily integrated into Wireless Body Area Networks (WBAN) in medical applications. This WBAN links the autonomous nodes that may be situated either in the clothes, on-body or beneath the skin of a person. This system typically advances the complete human body and the inter-connected nodes through a wireless communication channel.

A miniaturized rectangular shape narrowband MIMO antenna with reduced mutual coupling for C-band applications

A miniaturized rectangular shape narrow band multiple-input multiple-output (MIMO) antenna with I-shaped slot defected ground structure (DGS) for isolation improvement is discussed in this paper. To limit the surface waves between the adjacent patches, the DGS is etched between them. Antenna elements next to each other have a significantly reduced edge-to-edge spacing of 7.12 mm (). The complete size of the proposed MIMO antenna is . The MIMO antenna has a return loss less than dB over the operating band (7.41–7.91 Ghz ) with a lowest value of −46.77 dB. A comparative analysis of ECC (less than 0.32), DG (greater than 9.45), TARC (less than dB), and MEG (less than dB) are shown to validate the diversity performance of the proposed design. The performance parameters measured are in close agreement with the simulated result. The proposed MIMO antenna finds application in C band.

Bandwidth Enhancement of Bow-tie Microstrip Patch Antenna Using Defected Ground Structure for 5G

A microstrip antenna suffers from a narrow bandwidth because of the thickness of the substrate. This paper presents a wideband microstrip antenna by using Defected Ground Structure (DGS) on a bow-tie microstrip patch antenna. The cross-dumbbell shaped slot is used as DGS on the ground layer. The cross-dumbbell DGS slot is put on the backside of the transmission line. The antenna is designed using Computer Simulation Technology (CST) microwave studio and on the commercially printed circuit board substrate, i.e., the FR-4 substrate. The antenna is set for 5G applications, which use 3.67 GHz as the frequency center. By using DGS, the simulated reflection coefficient (S11) for VSWR ≤ 2 shows the fractional bandwidth increase from 2.6% to 10.45%. The measured reflection coefficient matches the simulated results where the measurement gives 13.37% for fractional bandwidth.

A Frequency-Reconfigurable Microstrip Antenna with Constant Dipole-Like Radiation Patterns Using Single Bias, Triple Varactor Tuning with Reduced Complexity

This work proposes a novel frequency-reconfigurable circular patch antenna incorporated with a rectangular slot and a narrow slot capable of producing constant dipole-like radiation patterns. The antenna compactness is achieved with the integration of the rectangular slot defected ground structure (DGS) on the ground. The proposed antenna is able to perform continuous frequency tuning between 1.91 and 2.77 GHz with a frequency ratio of 1.5:1, in addition to stable dipole-like radiation patterns. The resonant frequency of the antenna is controlled by tuning a simple DC biasing network that consists of three RF varactor diodes located on the narrow slot DGS. Implementing the DC biasing network at the narrow slot DGS while maintaining the large slot DGS helps the antenna miniaturization and maintains the constant dipole-like radiation pattern over all frequency tuning range. The results are validated via simulations and experimental validations in terms of reflection coefficients and the radiation patterns. Measurements indicated that an impedance bandwidth of 85 MHz is featured for each tuned frequency band, with dipole-like patterns and an average gain of 1.57 dBi.

A rectangular slot Yagi DGS microstrip filter with sharp rolloff and wide suppression band

Abstract A compact microwave lowpass filter based on defected ground structure (DGS), consisting of Yagi slot DGS resonators etched on the metallic ground plane of a microstrip line, is studied in this paper. The proposed lowpass filter was analyzed by parameter sweeping and optimal parameters were selected to design a prototype demonstrator filter. Measurements show the developed lowpass filter exhibits a 3dB cuto frequency of 3.07 GHz with a sharp transition between the passband and the stopband, low insertion loss of less than 0.6 dB in the passband and an in-band group delay of 0.4 ns. Moreover, an ultra-wide suppression band from 3.68 to over 20 GHz with a suppression level generally better than 20 dB is also observed from measurements.

Characterization of CP Radiations in a Planar Monopole Antenna Using Tuning Fork Fractal Slot for LTE Band13/Wi-Max and Wi-Fi Applications

In this paper, a novel antenna design comprising planar monopole with fractal slot defected ground structure for circularly polarized radiation is proposed. In the proposed antenna geometry, circular polarization radiation characteristics are obtained by defecting the ground structure with fractal slot. In this approach, CP characteristics are achieved by intensifying the level of cross polar component of the linearly polarized antenna upto a certain level by means of fractal slot inserted in ground structure. Antenna prototype with third order iterative tuning fork shaped fractal slot is fabricated and tested for the validation of simulated results. Parametric studies are also performed to exemplify the process of CP radiations. From the simulated and measured results, it is confirmed that the proposed antenna can be proficiently produced 10 dB return loss bandwidth (BW) nearly ≈37.4%, while 3-dB AR bandwidth (ARBW) is 15.5%, respectively. The proposed antenna can be a credible applicant for LTE Band 13/cellular/PCS /ASW/WiMAX and Wi-Fi applications.

Synthesis of Planar Filters Using Defected Ground Structure Miniaturized Hairpin Resonators

This paper presents an effective technique to suppress the spurious passbands in planar filters by using defected ground structure (DGS) resonators etched in the ground plane. The proposed miniaturized hairpin DGS slot resonator is researched in terms of its resonance frequency, corresponding coupling topologies, and filter design. The resonator and the topologies of coupled DGS resonators are simulated in a fullwave electromagnetic (EM) simulator. Using a curve-fitting technique, useful design formulas are proposed for filter synthesis. Using the synthesis procedure, a 3rd order filter design is simulated, manufactured and measured. The insertion loss of -3dB in the passband of 280MHz is observed, while the suppression of the spurious passbands up to 12GHz is more than 24dB.

Compact CoPlanar Waveguide-fed Ultra Wide Band and Band Switchable Slot Antenna for Cognitive Radio Front-end System

A compact coplanar waveguide (CPW)-fed ultra-wideband (UWB) slot antenna with four narrowband switchable states is presented in this paper. Cognitive Radio (CR) portable devices demand a compact antenna. In planar monopole antennas where a large space around the patch is getting wasted that can effectively be used in UWB slot antennas. The proposed antenna consists of a half-elliptical slot radiator fed through a half-elliptical shaped tuning stub to operate in the UWB mode for CR sensing. However narrowband antenna is required to operate in CR communication purpose. To operate in the narrowband mode the UWB slot antenna is fed through a defected ground structure (DGS) integrated CPW line. Frequency re-configurability is achieved by changing the DGS slot length using eight PIN diode switches. The proposed compact antenna can cover UWB frequency range from 3.14 GHz to 12 GHz. It has omnidirectional radiation pattern and also has high realized gain which is especially suited for CR front-end applications.

Investigation of a reconfigurable dual notched UWB antenna by conceptual circuit model and time-domain characteristics

In this paper, an ultra-wideband (UWB) antenna with reconfigurable performance is proposed. The antenna consists of a Ushaped radiation patch and a ground plane which is symmetric with the edge of the radiation patch. By using two open-ended L-shaped slots (OEL-S) and one U-shaped slot Defected Ground Structure, the dual notched bands at 3.5 GHz for WiMAX and 5.5 GHz for WLAN are obtained. Three switches are embedded in both L-shaped and U-shaped slots in order to achieve four switchable modes by switching them between ON and OFF states. There are three modes that the antenna can be switched in, which are dual, single and no band-notched modes. The measured result illustrates that the operation frequency band is from 2.7 GHz to 12 GHz ( VSWR<2). Moreover, the conceptual circuit model and time-domain characteristics of the antenna are also proposed to investigate the dual band-notched performance. (C) 2017 Wiley Periodicals, Inc.

A frequency-reconfigurable elliptical monopole antenna for cognitive radio networks

In this paper, an elliptical disk monopole antenna with seven switchable states, including an ultrawideband (UWB) state and six narrowband states, is presented. It consists of an elliptical disk radiator to operate in the UWB mode for cognitive radio (CR) sensing. To operate in the narrowband mode, the antenna is fed through a defected ground structure (DGS) integrated microstrip line. Frequency reconfigurability is achieved by changing the DGS slot length using six electronic switches. The simple proposed design can cover a wide range of frequency bands from 0.75 to 12 GHz, has an omnidirectional radiation pattern with high gain, and is especially suitable as a CR front-end. The fabricated prototype shows good impedance matching in the specified frequency range.

Miniaturized Dual-Band Negative Group Delay Circuit Using Dual-Plane Defected Structures

In this letter, a design for a dual-band negative group delay circuit (NGDC) using dual-plane U-shaped defected structures is presented. The center frequency and group delay (GD) time of each band are separately controlled by a defected microstrip structure (DMS) and a defected ground structure (DGS) with resistors connected across the DMS and DGS slots. To verify the design concept, the NGDC is designed, fabricated, and compared with the circuit simulation. To get a wideband bandwidth, two NGDCs with different center frequencies are connected in a cascade design. From the measurements, the GD times of -4.54 ±0.6 ns and -4.20 ±0.5 ns are obtained at 3.46-3.58 GHz and 5.10-5.20 GHz, respectively.

Compact microstrip low-pass filter with sharp selection characteristics using triple novel defected structures for UWB applications

In this article, a novel band-stop filter using defected ground structure (DGS) and defected microstrip structure (DMS) with triple T-shaped slot and a pair of protruded T-shaped strips inside the triple rectangular slots is presented. Using these DGS and DMS slots, a quasielliptic low-pass filter (LPF) was designed, fabricated, and tested. The transmission zeros of the slots can be easily controlled by changing the protruded T-shaped strip and slot dimensions, without changing the area taken by the structure. The experimental results show good agreement with simulation results and demonstrate that excellent stop-band performance could be obtained through the proposed LPF. The filters have a cutoff frequency of about 3.14 GHz. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1007–1010, 2014

COLLOCATED MIMO ANTENNA WITH REDUCED MUTUAL COUPLING USING SQUARE RING DGS

A multimode collocated microstrip patch antenna with reduced mutual coupling is proposed in this paper. The antenna is designed to achieve polarization and pattern diversity for use in multiple- input-multiple-output (MIMO) terminals. The four-port antenna resonates at 2.45GHz and have total dimension of 1.03‚ with reduced mutual coupling (< i20dB) between its ports. It consists of a simple square patch and a square ring antenna, with a novel square ring slot defected ground structure (DGS). Square ring slot on ground improves isolation by 7dB by reducing surface waves in both E and H planes. With defected ground structure (DGS), coupling between patch and ring antennas is about i25dB and correlation factor is less than 0.1. Pattern diversity, mutual coupling and correlation coe-cient between signals for a four-port antenna fabricated using FR4 substrate is discussed in this paper.

A Compact Ultra-Wideband Monopole Antenna with Dual Bandstop Characteristics

A compact and simple ultra-wideband microstrip-fed planar antenna with double bandstop characteristic is presented. The antenna consists of a rectangular monopole and two W-shaped slots inserted into the radiating patch and the truncated ground plane. By using a W-shaped slot defected ground structure (DGS) in the feedline, a stopband of 800 MHz (from 5.1 to 5.9 GHz) for band rejection of wireless local area network (WLAN) is achieved. To obtain the other stopband (from 3.7-4.4 GHz), a same shaped slot is etched into the monopole. Moreover, the two stopbands can be controlled by adjusting the length of the slot respectively. The simulation results show that the designed antenna, with a compact size of 38.5 mm×42.5 mm, has an impedance bandwidth of 2.811 GHz for voltage standing wave ratio (VSWR) less than 2, besides two frequency stopbands of 3.74.4 GHz and 5.15.9 GHz. Moreover, the main features including omnidirectional H-plane radiation patterns and the appropriate impedance characteristic are achieved by beveling the radiating patch and the microstrip-fed line of the proposed antenna.

Design and implemention of very compact band‐stop filter with petal‐shaped stub for radar applications

AbstractIn this article, we introduce a compact microstrip band stop filter (BSF) at X‐band frequency range and this shall be used in local oscillator chain for X‐band transceiver. Presented microstrip filter consists of a transmission line with a petal‐shaped stub and a ground plane with a modified rectangular‐shaped defected ground structure (DGS). Operation frequencies of the filter can be easily controlled by changing four protruded T‐shaped strips in the petal‐shaped structure. The DGS slot evolved from photonic band gap (PBG) is embedded to achieve a good impedance matching and the required filter's characteristics. The proposed band‐stop filter has wide bandwidth from 8–12 GHz for X‐band Communications that can be used in Radar applications. Good agreement between simulated and measured results cause that excellent stop‐band performance could be obtained through the X‐band frequency range. The proposed microstrip filter fabricated on a Rogers RT/Duroid 5880 substrate with a relative dielectric constant of 2.2 and has a very small size of 10 × 15 mm2. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1130–1132, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27518