Defected Ground Structure Research Articles

Bioinspired planar switched beam network using Butler matrix on a flexible substrate targeting multifaceted millimeter-wave applications

Abstract This paper details the design and development of a planar switched beam network using 4 × 4 Butler matrix (BM) over a thin and flexible type biocompatible substrate. Four mils thick liquid crystal polymer (LCP) is used as a substrate here (ϵr = 2.92, tanδ = 0.002). The proposed design is centered at 28 GHz, targeting commercial millimeter-wave applications. Floral-shaped antenna with defective ground structures has been implemented as basic radiating elements. The whole structure is based on microstrip line configuration. The architecture occupies an area of 23.85 × 19.20 mm2 over the LCP substrate. Individual components of the BM are detailed here, followed by a system analysis of the whole integrated structure. The present work also covers the electrical equivalent circuit modeling of the whole beam-forming network. The fabricated prototype offers better than 18 dB return losses at each input port for the desired frequency band with 6 dBi (max.) peak gain and 500 MHz bandwidth around the center frequency. Port-to-port isolation of better than 15 dB is achieved with this topology. Experimental and simulated results are in good agreement in all aspects. A comparative study is also chalked out to highlight the significance of the current research work with respect to alike earlier reported structures.

Design and analysis of wideband four-port multiple input multiple output antenna using defective ground structure for 5G communication

This research work describes a compact four-port multiple input multiple output (MIMO) antenna using defective ground structure (DGS), and it perfectly supports the n77, n78, and n79 frequencies in 5G new radios (NR) bands. It can cover a wideband from 3.4 to 5.4 GHz with good impedance matching. The pair of antenna elements are orientated opposite to another pair with DGS. Due to this technique, it has minimal complexity, is less expensive, and improves isolation. It has also improved the frequency band's reflection coefficient and range using MIMO antenna with different stub lengths. Because it is less expensive, FR-4 substrate is used in the implementation of all antennas. Each antenna element has two identical stubs linked to the primary radiator. On the primary radiating element, a ''HI'' slot is created. The partial ground enhances impedance matching and radiation properties throughout the targeted band. <span>The total dimensions of the four-port MIMO antenna are 46×30×1.6 mm<sup>3</sup>. The array elements' mutual coupling in the simulation is -14 dB. The ECC value is below 0.01, and the diversity gain (DG) is less than 10 dB. The suggested designs' measured gain ranges from 10 to 11.0 dB, and the radiation efficiency is nearly 91%.</span>

Compact 3-D Printed Phase-Shifting Coupler With Decoupling Column and Defected Ground Structures for Millimeter Wave Applications

Compact 3-D Printed Phase-Shifting Coupler With Decoupling Column and Defected Ground Structures for Millimeter Wave Applications

Improved design and performance of the global rectenna system for wireless power transmission applications around 2.45 GHz

This work proposes a new conception of the global microstrip rectenna system operating around 2.45 GHz. This improved rectenna system associates a receiving antenna with a rectifier circuit. This rectenna is printed on an FR4 substrate. The proposed antenna is a 1×4 microstrip antenna patch array with pentagonal patches using the defective ground structure method and operates with circular polarization. To show the effectiveness of this array, the results obtained by the computer simulation technology microwave studio (CST MWS) software prove that this array is good in terms of high gain, high directivity, high efficiency, wideband, small volume, and well-adaptation, and all these results are confirmed by another solver high-frequency structure simulator (HFSS). The improved rectifier is a microstrip rectifier that uses an HSMS2852 Schottky diode by using a series topology. The effectiveness of this rectifier is proved by the simulation results using advanced design system (ADS) software in terms of well-matching input impedance, high efficiency, and important output direct current (DC) voltage value. The proposed rectenna system is more efficient compared with the existing works and is very appropriate for several applications of wireless power transmission to power supply electronic instruments in various fields cleanly on our planet.

Filtenna Designed with Defected Ground Structure (DGS) for Ultra-wideband Applications

In microwave imaging applications, filter and antenna are the key components as front-end devices and function independently. Antenna radiates and receives signals to or from nearby scattered objects while filter is used to suppress unwanted signals noise before and after the required bandwidth. Current antennas suffer from high loss, bandwidth limitation and impedance mismatch and deteriorate their performance near the band-edges if connected as a stand-alone device. Due to the current trend towards simplicity and size reduction, researchers are focusing on integrating the filter and antenna into a single module called integrated filter-antenna (IFA) or filtering antenna (filtenna). These would improve the noise performance of the system and pre-filtering requirements such as complexity algorithm in inverse scattering techniques This paper introduces a novel contribution in the field of UWB antenna design by incorporating Defected Ground Structure (DGS) on both the antenna and filter. Thus, the main aim of this research is to conduct detail parametric studies of the proposed integrated filter-antenna with defected ground structure (DGS) to enhance the performance of imaging system. The proposed IFA will be analysed on Rogers RO4003C dielectric substrate by using EM tool, Computer Simulation Technology (CST) and measured using R&S Vector Network Analyzer (VNA). A compact ultra-wideband (UWB) filter and UWB elliptical antenna are designed and examined in detail before combining the devices. Different types of DGS are designed and act as the ground layer of the proposed filtering antenna. The bandwidth of each design is then compared with and without the existence of DGS. The results show that the proposed IFA with DGS implementation achieve the targeted objective, with compact size, enhanced bandwidth and better performance compared to the conventional design of filter and antenna. By integrating filter and antenna into one subsystem, it can help to reduce the loss and enhancing the bandwidth of the system thus letting the antenna to operate at more different frequencies that fall within the range. Both simulated and measured results prove that by integrating filter and antenna into one module, a low loss and larger bandwidth can be accomplished. High performance compact IFA can act as microwave transceiver to improve the overall performance of the microwave imaging system, MIS.

Performance Signature and Analysis of Patterned Surfaces Trapezoidal Patch Antenna Array with Defected Ground Structure

Performance Signature and Analysis of Patterned Surfaces Trapezoidal Patch Antenna Array with Defected Ground Structure

Design of Enhanced Wide Band Microstrip Patch Antenna Based on Defected Ground Structures (DGS) for Sub-6 GHz Applications

In this paper a comprehensive comparative study of three distinct microstrip patch antenna (MPA) designs, each optimized for the sub-6 GHz applications, is presented. The initial design phase utilized a Rogers RT 5880 substrate with a permittivity (εr1) of 2.2 and a thickness(H1) of 1.42 mm. The proposed model achieved a resonance band ranging from 4.8 to 7 GHz, with a bandwidth of 2.2 GHz and a return loss (S11) of -20 dB. Subsequent enhancements involved integrating a Barium Strontium Titanate (BST) thin film (εr2 = 250, thickness(H2) = 0.005 mm), effectively shifting the operational band to 3.5-5.3 GHz. The final design iteration, which incorporated both BST and a Defective Ground Structure (DGS), represented a substantial advancement, achieving wideband operation from 1.8 to 6 GHz, expanding the bandwidth to 4.2 GHz, and improving the S11 to -25 dB. This integration also resulted in a compact antenna size of 30 x 26.5 x 1.42 mm³. These findings underscore the synergistic impact of BST and DGS in enhancing MPA design, marking a significant progression in antenna technology, vital for a range of wireless communication.

Design of a Low Sidelobe Feed Network Based on the Louver-Shaped Defected Ground Structure

In this paper, a low sidelobe feeding network has been developed utilizing the louver-shaped defected ground structure (DGS). By adjusting the louver-shaped DGS, the output amplitude and phase of the corresponding ports can be altered, minimizing deviations from theoretical values. This enables antenna arrays equipped with this feeding network to more easily achieve low sidelobe performance. The impact of the louver-shaped DGS on the amplitude and phase of each port in the power divider within the feeding network is analyzed, and a 16-channel feeding network incorporating the louver-shaped DGS has been designed, fabricated, and then measured. The test results indicate that the performance of the line-feeding network is effectively improved by designing and adjusting the louver-shaped DGS. Through the debugging procedure, the amplitude deviation of the feeding network has been reduced from ±0.45 dB to ±0.2 dB, while the phase deviation of the feeding network has been reduced from ±8° to ±2.5°, and the maximum value of the first sidelobe has been reduced from −24.2 dB to −28.1 dB.

Microstrip Patch Antenna Design for Enhanced Bandwidth and Harmonic Suppression

Antennas are essential components in wireless communication systems, often requiring a delicate balance between achieving wide bandwidth and suppressing harmonics effectively. This study focuses on the integration of defected ground structures (DGS) to enhance antenna performance. Through rigorous experimentation and analysis, the research aimed to optimize microstrip patch antenna designs for improved bandwidth while maintaining efficient harmonic suppression. The investigation involved parametric studies to determine the optimal dimensions and configurations of DGS for wideband-stop characteristics. Simulation tools were utilized to analyse the impact of DGS on the antenna's behaviour, leading to the development of an accurate equivalent circuit model. Current distribution analysis provided insights into the radiation pattern and impedance matching of the antennas with and without DGS. Experimental results demonstrated significant improvements in antenna performance. The measured reflection coefficient values indicated successful harmonic suppression, with reductions around 22 dB at the third harmonic frequency. The input impedance values were optimized to utilize a modified ground plane featuring diagonal edges and a rectangular slot cut to design compact antennas, contributing to enhanced bandwidth and improved overall performance. Radiation pattern measurements validated the effectiveness of the optimized designs. This study demonstrates successful integration of DGS into slot antennas, achieving wider bandwidth with robust harmonic suppression. Experimental results validate design strategies, offering insights for high-performance slot antennas in modern communication systems.

A 4-Element UWB MIMO Antenna System with High Isolation Performance

This paper proposes a 4-element multiple-input multiple-output (MIMO) antenna system, which is intended for ultra-wideband (UWB) applications. The antenna has a dimension of 92 × 70 × 1.6 mm3. It achieves element isolation via the defected ground structure (DGS) and symmetric E-shaped branch structures design. The realized operating bandwidth is from 3 GHz to 18 GHz, with 15 dB isolation within the whole wide band. The envelope correlation coefficient (ECC) is less than 0.01 with diversity gain (DG) greater than 9.95. The prototype is fabricated and measured to verify its potential applications for UWB MIMO communication.

Compact antenna for higher order harmonic reduction using efficient defected ground structure

To suppress higher order harmonic using Inverted ‘U’ shapes defected ground structure (DGS) with two symmetric inverted ‘L’ shape stubs is presented here. At first, a study was made on the resonant frequencies of traditional line feed microstrip antenna. An Inset feed with inverted slots is introduced to eliminate all the higher-order modes up to the third harmonics in the WiMAX Band. To get wide-area stopband characteristics, dimensions and position of DGS and stubs are optimized. The proposed DGS area along with the radiated patch is more compact and stable rather than in a few reported articles. This microstrip antenna is designed and perfectly matches the WiMAX frequency band (3.3–3.7 GHz) application while suppressing other frequencies. The proposed inverted ‘U’ shapes DGS are designed with an equivalent circuit. Finally, the proposed Stub with DGS Antenna (SDA) is fabricated and measured. The proposed structure is verified with measurements and it has satisfactory gain, radiation pattern and reflection coefficient at 3.5 GHz.

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

SoilTAG: Fine-Grained Soil Moisture Sensing Through Chipless Tags

Soil moisture sensing plays an important role in agriculture, especially in greenhouses or vertical farms. However, existing soil moisture sensing systems are either expensive and require batteries or suffer from low accuracy, preventing their real-world applications. This paper introduces SoilTAG, a battery-free, chipless tag-based high accuracy soil moisture sensing system. The key insight is that the tag's resonator can convert changes in soil moisture levels into changes in the tag's frequency response. However, two challenges need to be addressed before applying the system to the real world. First, how to design a resonator whose frequency response is sensitive to even small moisture changes, which is the basis for high-precision moisture sensing. To solve the challenge, we design a special structure (i.e., a defected ground structure) as the tag's resonator and optimize its key parameters to increase the frequency response sensitivity for different soil moisture levels. Second, how to design a robust soil moisture feature that is independent of the tag's location changes, since the frequency response varies by both the tag location and soil moisture. To deal with this challenge, we introduce a relative frequency response feature whose amplitude ratio is only related to soil moisture levels and independent of the tag location changes. Extensive experiments show that SoilTAG achieves <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$90th$</tex-math></inline-formula> percentile moisture sensing error of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$2\%$</tex-math></inline-formula> , <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$3.64\%$</tex-math></inline-formula> , and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$8\%$</tex-math></inline-formula> when the distance between transmitter and tag is 6 m, 10 m, and 13.9 m. Compared to current commodity sensors, SoilTAG saves the cost per sensor by more than 70%.

Study on Defected Ground Structure Models with Miniaturized Patches for Broadband Wireless Systems

Study on Defected Ground Structure Models with Miniaturized Patches for Broadband Wireless Systems

Design and Miniaturized a High Suppression Stop band Micro strip Low Pass Filter by using Slot Defected Ground Structure for 5G Applications

Design and Miniaturized a High Suppression Stop band Micro strip Low Pass Filter by using Slot Defected Ground Structure for 5G Applications

Performance analysis of the dual-band trapezoidal antenna array for ultra-wideband application

Designing a wireless transmission system with high data rates, high fidelity, and small size is a tough undertaking that has become more popular in the digital age. One of the most important components of wireless communication systems, such as wireless LANs, mobile WIMAX, and Bluetooth devices, is the design of an efficient antenna system. The new circular slot Trapezoidal patch antenna array, which operates in the ultra wide band frequency range of 3.1 GHz to 10.6 GHz, is introduced in this study. The FR4 substrate on which the antenna system is built has a dielectric constant of 4.4. The CST microwave studio suite is used to develop and analyze the performance of the compact structure patch antenna array. Antenna performance is examined in the frequency range of 2 GHz to 5 GHz. Antenna array resonance frequency is 3.1 GHz. By inserting a quarter wave line between the SMA connection and the micro stripline, 50 ohm impedance matching may be achieved. In comparison to previous studies, the intended antenna array has a minimum VSWR of 1.18, a maximum radiation efficiency of ?4.842 dB, and a directivity of 8.645 dBi. Using network analyzer, the test and simulation data were analyzed. The intended use of the antenna array system is for biomedical imaging and body area networks. Abbreviations: UWB: ultra wideband; EMI: electromagnetic interference; MIMO: multiple input multiple output; WLAN: wireless local area network; VSWR: voltage standing wave ratio; AVA: antipodal vivaldi antenna; DGS: defected ground structure; RF: radio frequency.

Broadband Balanced-to-Balanced Filtering Power Divider Using HMSIW-SSPP Transmission Line.

In this paper, a novel broadband balanced-to-balanced (BTB) filtering power divider (FPD) utilizing the half-mode substrate-integrated waveguide and spoof surface plasmon polariton (HMSIW-SSPP) hybrid transmission line is introduced. Initially, a new HMSIW-SSPP unit cell is proposed, demonstrating a lower upper cut-off frequency compared to the classical HMSIW-SSPP unit cell. Building upon this unit cell, a bandpass BTB FPD is devised employing dual-layer stacked substrates, enabling independent control over the passband's lower and upper cut-off frequencies through specific physical dimensions. Additionally, the incorporation of isolation resistors and defected ground structures in the BTB FPD enhances differential-mode isolation and common-mode (CM) suppression between output ports. A manufactured and tested BTB FPD prototype validates this design method, showcasing a broad fractional bandwidth of 52.31% (6.72-11.48 GHz), output port isolation surpassing 14.25 dB, and transmitted CM suppression exceeding 34.05 dB.

Design and diversity performance analysis of C shape engraved miniaturised, and high gain Quad-Port MIMO antenna for 5 G and P2P communication

The 4-Port multiband operated MIMO antenna operating at 4 GHz, 6 GHz and 9 GHz is proposed to target the 5 G and P2P communication applications. The electrical size of the 4-Port antenna structure is 0.8λ × 0.48λ. The unique shape of a single radiating patch element is identified by engraving a circular shape patch element and modifying the shape of the feedline. The optimisation in terms of return loss was achieved based on the defected ground structure and changing radius of different elements of the patch structure. The 2-Port and 4-Port MIMO antenna structures are designed using the FR4 substrate and their return loss is compared and examined. The proposed design provides a minimum return loss of −22 dB, peak bandwidth of 2.25 GHz, peak gain of 4.67 dB, and normalised directivity of 187°. Different MIMO diversity parameters are analysed. The proposed design provides an envelope correlation coefficient of 0.01, Diversity gain near 10 dB, mean effective gain of almost zero, channel capacity loss of almost zero and Mean effective gain within the acceptable range. The overall Performance of the Proposed Design is compared with other 4-Port design structures and it represents healthy gain, multiple band response and proper diversity parameters making it suitable for the 5 G and P2P communication applications.

Characteristics mode analysis based wideband Sub-6 GHz flexible MIMO antenna using a unique hybrid decoupling structure for wearable applications

This article presents a compact flexible four-element multiple input multiple output (MIMO) antenna for Sub-6 GHz wearable applications. A wideband monopole antenna with a modified edge tapered radiator and a lowered ground plane is replicated to form a four-element antenna. The proposed antenna is fabricated on a flexible polyethylene terephthalate (PET) substrate and holds an overall dimension of 65 × 56 × 0.25 mm3. The antenna has a measured bandwidth of 3.55–5.3 GHz with a peak gain of 4.9 dBi. A novel hybrid decoupling structure with a neutralization line in the radiator and a unique defective ground structure (DGS) suppresses the coupling current and provides isolation better than −24 dB throughout the bandwidth. The antenna design evolution is explained using characteristics mode analysis (CMA). The MIMO diversity performance is relatively good with MIMO diversity metrics showing envelope correlation coefficient (ECC) < 0.001, diversity gain > 9.99, total active reflection coefficient (TARC) < −10 dB, channel capacity loss (CCL) < 0.3 bps Hz−1 and multiplexing efficiency (ME) < −0.5. Specific absorption rate (SAR) analysis of the antenna is performed to check the antenna’s suitability in wearable applications and the proposed antenna exhibits 0.745 W kg−1 and 0.326W kg−1 for 1g and 10g of tissue respectively which is much less than the permissible international standards.

Design and optimization of broadband CPW rectenna for RF energy harvesting

ABSTRACT Wireless sensor networks (WSNs) are widely used in a variety of sectors, including the surveillance, healthcare, and military, and so on. The high cost and short lifespan of wireless sensor networks prohibit emerging and low-income nations for using their benefits. This article proposes a compact, low cost, and broadband coplanar waveguide rectenna with a simple novel ground plane operate in band range of 4.8–5.5 GHz (700 MHz) for an effective solution to radio frequency (RF) energy harvesting applications in WSNs. A parametric study of distinct antennas is also conducted to strengthen the attributes of the proposed antenna. The defected ground structure created on the co-plane offers 105° measured half power beamwidth (HPBW) in the H-plane for wide angular coverage. As a result, design alignment does not need to be extremely perfect in order to make conversion efficiency constant. The rectifying circuit is made compact by using a two-stub impedance matching network. At load resistance of 1k Ω, the power conversion efficiency of the proposed rectenna for a low input power level of −10 dBm is 27.2% (simulated) and 20.1% (measured) while its maximum value is 52.5% (simulated) and 50.1% (measured) for input power level of 10 dBm.