Electromagnetic Band Gap Ground Research Articles

A wideband, thin profile and enhanced gain microstrip patch antenna modified by novel mushroom-like EBG and periodic defected ground structures

This paper presents a wideband, thin-profile and enhanced-gain microstrip patch antenna improved by using a novel mushroom-like Electromagnetic Band Gap (EBG) structure and forming periodic Defected Ground Structures (DGS) on the ground plane. The proposed antenna operates between 9.56 and 14 GHz and has 4.44 GHz–10 dB impedance bandwidth. With A4, the gain of the reference antenna is increased by 64.4%, while a 38% bandwidth is also achieved. The parametric analyses carried out on the metallic part area of the novel EBG patch indicated that when the area of the used EBG patches are approximately three quarters or less of the conventional ones, greater gain values for the designed antenna are obtained. This relation between the EBG patches and the antenna gain can be pointed out as the novelty of the study. The results were analysed by the simulations carried out with CST Microwave Studio and were verified by measurements from manufactured prototypes.

A High Performance All-Textile Wearable Antenna for Wristband Application.

A compact, conformal, all-textile wearable antenna is proposed in this paper for the 2.45 GHz ISM (Industrial, Scientific and Medical) band. The integrated design consists of a monopole radiator backed by a 2 × 1 Electromagnetic Band Gap (EBG) array, resulting in a small form factor suitable for wristband applications. An EBG unit cell is optimized to work in the desired operating band, the results of which are further explored to achieve bandwidth maximization via floating EBG ground. A monopole radiator is made to work in association with the EBG layer to produce the resonance in the ISM band with plausible radiation characteristics. The fabricated design is tested for free space performance analysis and subjected to human body loading. The proposed antenna design achieves bandwidth of 2.39 GHz to 2.54 GHz with a compact footprint of 35.4 × 82.4 mm2. The experimental investigations reveal that the reported design adequately retains its performance while operating in close proximity to human beings. The presented Specific Absorption Rate (SAR) analysis reveals 0.297 W/kg calculated at 0.5 W input power, which certifies that the proposed antenna is safe for use in wearable devices.

Scanning Angle Extension of a Millimeter-Wave Antenna Array Using Electromagnetic Band Gap Ground

A compact phased array with extended beam steering characteristics for the millimeter-waveband of the fifth-generation (5G) applications is presented in this communication. An E-shaped patch antenna placed on an electromagnetic bandgap ground (EBGG) with operating bandwidth of 24.2–27.5 GHz is used as the basic building block of the eight-element linear array. The array utilizes both the in-phase reflection characteristic for broad element radiation pattern and the bandgap characteristic for mutual coupling reduction for limited inter-element spacing of the proposed array. The existence of the EBGG enables a compact array with the inter-element spacing of around 0.4 wavelengths at the center frequency, yet the isolation between each element is still above 17 dB within the whole band of interest, which also helps to increase the array directivity at large scanning angles. The scanning angle of the array with the electromagnetic bandgap (EBG) structure ranges from −75° to 75° at 26 GHz within 3 dB scanning loss. The proposed EBGG extends the antenna array’s spatial coverage and enables a compact size of the array, which is very attractive for 5G millimeter-wave (mm-wave) application.

Performance Analysis of Wearable Dual-Band Patch Antenna Based on EBG and SRR Surfaces.

This paper presents the performance comparison of a dual-band conventional antenna with a split-ring resonator (SRR)- and electromagnetic bandgap (EBG)-based dual-band design operating at 2.4 GHz and 5.4 GHz. The compactness and dual-frequency operation in the legacy Wi-Fi range of this design make it highly favorable for wearable sensor network-based Internet of Things (IoT) applications. Considering the current need for wearable antennas, wash cotton (with a relative permittivity of 1.51) is used as a substrate material for both conventional and metamaterial-based antennas. The radiation characteristics of the conventional antenna are compared with the EBG and SRR ground planes-based antennas in terms of return loss, gain, and efficiency. It is found that the SRR-based antenna is more efficient in terms of gain and surface wave suppression as well as more compact in comparison with its two counterparts. The compared results are found to be based on two distinct frequency ranges, namely, 2.4 GHz and 5.4 GHz. The suggested SRR-based antenna exhibits improved performance at 5.4 GHz, with gains of 7.39 dbi, bandwidths of 374 MHz, total efficiencies of 64.7%, and HPBWs of 43.2 degrees. The measurements made in bent condition are 6.22 db, 313 MHz, 52.45%, and 22.3 degrees, respectively. The three considered antennas (conventional, EBG-based, and SRR-based) are designed with a compact size to be well-suited for biomedical sensors, and specific absorption rate (SAR) analysis is performed to ensure user safety. In addition, the performance of the proposed antenna under bending conditions is also considered to present a realistic approach for a practical antenna design.

A Fabry-Perot Cavity Antenna With Non-Uniform Superstrate and EBG Ground for High Gain and High Aperture Efficiency

A design of high-gain Fabry-Perot cavity (FPC) antenna is presented with non-uniform frequency selective surface (FSS) superstrate and electromagnetic band gap (EBG) reflecting ground. The non-uniform FSS superstrate and EBG ground are utilized to flexibly control the attenuation constant <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\alpha $ </tex-math></inline-formula> over a large antenna aperture while ensuring the resonance condition of the FPC. The uniformity of the amplitude of the aperture field is improved significantly while obtaining appropriate radiation efficiency. Therefore, the high gain and high aperture efficiency can be achieved within a desirable bandwidth. The theoretical gain estimation is conducted to prove the superiority of the proposed antenna over a referenced uniform one. A straight-forward design methodology is proposed based on the radial leaky-wave theory and the modified transverse equivalent network (TEN) model. The non-uniform high-gain FPC antenna with a diameter of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$6.6\lambda _{0}$ </tex-math></inline-formula> is designed at the frequency of 15 GHz. Simulated results show that a gain of 24.6 dBi with an aperture efficiency of 67.9% has been achieved. The measured gain is 24.0 dBi with an aperture efficiency of 58.4%. The 10dB return loss bandwidth and 3 dB gain bandwidth are 5.3% and 3.2%, respectively. The proposed antenna overcomes the limit on aperture efficiency and gain of conventional uniform FPC antennas, and the presented methodology can guide the design of two-dimensional non-uniform high-gain FPC antennas.

Wideband microstrip antenna for the detection of solutes in water

AbstractEffective detection of solutes in water has always been a challenging issue in real‐time. This article presents a technique to detect solutes such as table sugar (CHOO3), common salt (NaCl), and combinations thereof in water using a wideband microstrip antenna with an electromagnetic band gap ground structure. An antenna is designed and fabricated to operate at the bandwidth of 3 GHz with a stable gain of 9 dBi maintaining voltage standing wave ratio ≤ 2. The uniquely designed antenna works as a sensor in its near field to sense solutes in water as a function of the resonant frequency. Apart from sensing solutes, the proposed technique also efficiently detects temperature of soft drinks. As temperature of soft drinks changes, reflection characteristics of an antenna change too. The results of the experiments show that as the concentration of the solute increases, the return loss decreases. The beauty of this technique is its efficient detection without any physical contact with a solution and without disturbing the chemical processes inside the solution. This method can be quite useful for food regulation boards to analyze and detect the contents of beverages, soft drinks and any consumable liquid, whether hot or cold.

Wearable EBG-Backed Belt Antenna for Smart On-Body Applications

This article presents an innovative belt antenna with an electromagnetic band-gap (EBG) ground plane made of textile materials. The antenna can be applied in a smart belt system to set up a communication link with other electronic devices and/or host a variety of sensors to track human motions. The proposed belt antenna works at 2.45 GHz in the industrial, scientific, and medical radio band for Bluetooth low energy communications. Considering the effect the human body would have on the performance of a belt antenna, a textile ground plane is designed to be integrated into the trouser fabric behind the belt to provide isolation from the body and simultaneously improve antenna radiation characteristics. Through the application of the ground plane, the belt antenna achieves a maximum realized gain of 7.94 dBi and a minimum specific absorption rate of 0.04 W/kg at 0.5 W input power. During the design process, characteristic mode analysis is used to explore the underlining principle and further optimize the antenna performance. Two typical EBG structures are analyzed in detail for this application scenario. The suspended transmission line method is used to evaluate EBG performance variations when the textile ground plane is bent. A prototype of such a system is fabricated and tested. Experimental results shows that the belt antenna, together with the textile EBG ground plane, is an excellent candidate for a smart belt system with desirable radiation pattern, efficiency, and safety limit.

Development of 60-GHz millimeter wave, electromagnetic bandgap ground planes for multiple-input multiple-output antenna applications

For 60-GHz band communications, both the mutual coupling and transmission distance restrict the performance of a multiple-input multiple-output (MIMO) antenna array. Several studies presented different types of meta-materials and electromagnetic bandgap (EBG) structures to improve the performance of a MIMO antenna array at the 60-GHz band. In this paper, we presented the four-element MIMO patch antenna with different types of EBG structures for the millimeter wave (mmW)communications at the 60-GHz unlicensed industrial, scientific, and medical band. The single element of the MIMO antenna array covered the mmW band from 57 GHz to 63 GHz having the dimensions of 1.3 mm × 1.8 mm × 0.1 mm. We developed a set of square-shaped, cross-shaped, and complex-slotted EBG ground planes between the antenna elements for the performance improvement. All the three EBG ground planes provided significant coupling reduction between the mmW MIMO antenna elements. The proposed EBG structures exhibited wide bandgap characteristics and improved scattering parameters in the desired frequency band. In contrast with the cross- and complex-slotted, the square-shaped EBG structure substantially improved the overall gain of MIMO antenna array. In addition, the square-shaped EBG reformed the maximum beam and enhanced the far-field gain pattern in the desired direction. Experimental results conducted with the fabricated prototypes showed a good agreement with the simulation results and adequately covered the 60-GHz band. The low-profile and salient features of the proposed MIMO antenna array shows the potential for on-chip applications at 60 GHz.

Isolation improvement of a two‐port PIFA for MIMO using a planar EBG ground

AbstractIn this article, the mutual coupling reduction of a two‐port planar inverted‐F antenna (PIFA) using a planar electromagnetic bandgap (EBG) structure is presented and investigated for multiple input multiple output/diversity applications. The planar EBG structure is designed for etching on the ground plane of the device. The EBG and the antenna design parameters are identified and the frequency scalability of the design is illustrated by showing two separate designs at 2.45 and 3.50 GHz. The optimized 2.45 GHz design demonstrates 25 dB more coupling reduction compared to the state of the art PIFA with a slot on the ground. Analyses of efficiency and effective diversity gain are also performed which show excellent performance.

Parametric Analysis of Wearable Vialess EBG Structures and Its Application for Low Profile Antennas

Electromagnetic Bandgap (EBG) structures are one class of metamaterial with attractive properties that unavailable in nature and widely used for improving the electromagnetic performance. Its In-phase reflection frequency band is indicated as operation frequency band, whose characteristic is closely related to the parameters of EBG structure, such as patch width (w), gap width (g), substrate height (h) and substrate permittivity (e). The presence of via within EBG structure is associated with design and fabrication complexities, which led the researchers to study uniplanar EBG. These structures require no via and can easily be fabricated and integrated with RF and microwaves alication. Therefore, an investigation study on the effect of the parameters of the vialess EBG surface and some design guidelines have been obtained. An example of an antenna integrated with EBG is also studied. The result indicates that the EBG ground plane significantly improves the work efficiency of the antenna in a particular frequency band.

Design and SAR Analysis of Wearable Antenna on Various Parts of Human Body, Using Conventional and Artificial Ground Planes

This paper presents design and specific absorption rate analysis of a 2.4 GHz wearable patch antenna on a conventional and electromagnetic bandgap (EBG) ground planes, under normal and bent conditions. Wearable materials are used in the design of the antenna and EBG surfaces. A woven fabric (Zelt) is used as a conductive material and a 3 mm thicker Wash Cotton is used as a substrate. The dielectric constant and tangent loss of the substrate are 1.51 and 0.02 respectively. The volume of the proposed antenna is 113×96.4×3 mm3. The metamaterial surface is used as a high impedance surface which shields the body from the hazards of electromagnetic radiations to reduce the Specific Absorption Rate (SAR). For on-body analysis a three layer model (containing skin, fats and muscles) of human arm is used. Antenna employing the EBG ground plane gives safe value of SAR (i.e. 1.77W/kg 2W/kg). The efficiency of the EBG based antenna is improved from 52 to 74%, relative to the conventional counterpart. The proposed antenna can be used in wearable electronics and smart clothing.

Electromagnetic band gap‐dipole sub‐array antennas creating an enhanced tilted beams for future base station

A novel customised electromagnetic band gap (EBG)-dipole sub-array antenna with a tilted beam for future base-station applications is presented. An enhanced tilted beam for the base-station antenna is one of the safest methods to increase radio coverage area adhering to the strict power requirements. An array of four dipole-EBG elements is designed demonstrating the enhanced down-tilt beam. Each single element consists of dipole antenna mounted on a customised EBG ground plane created by connecting several unit cells of the EBG. The proposed array radiates a tilted beam in order to achieve a high directivity at fixed down-tilt angle. The array antennas are simulated, fabricated and measured. The directivity of 11 dB is measured at the angle of 28° at 3.5 GHz. This directivity is 1.9 dB higher than the reference case that uses the broadside single element. In addition, the EBG-dipole array that can be mechanically tilted is designed. The proposed array antenna exhibits acceptable impedance matching across the operational frequency band.

Dispersion Analysis and Design of Planar Electromagnetic Bandgap Ground Plane for Broadband Common-Mode Suppression

Planar electromagnetic bandgap (EBG) structure designed for broadband common-mode suppression is proposed. A uniplanar compact photonic-bandgap (UC-PBG) structure with periodic center slots is etched on the ground plane to obtain broadband common mode suppression while minimally disturbing the differential signal within the designed bandwidth. Dispersion analysis has been conducted for both common (even) and differential (odd) mode signals. Good signal integrity is observed in both simulated and measured results. The fractional bandwidth of the proposed EBG ground plane is around 80 % with common-mode suppression below -15 dB. The proposed EBG ground planes may be applicable for systems requiring low- cost and simple solutions in designing high-speed differential interlinks operating above 5 Gbps.

Annular Slot Loaded High-Impedance Ground Plane

High-impedance surfaces like electromagnetic band gap (EBG) ground planes have been used to realize low profile antennas. In this paper, an alternative ground plane design is presented for antennas with circular current distributions, which consists of an annular slot backed by a thin grounded substrate. The slot ring generates a high-impedance condition at a resonant frequency in the vicinity of the slot. This annular slot loaded ground plane results in efficient radiation of the low profile antenna in the broadside direction. Since the slot loaded ground plane consists of a single slot ring rather than periodic structures, it is much simpler to construct than the standard EBG ground plane. Numerical simulations and experimental measurements are shown to validate the design concept and are compared with a mushroom-type EBG ground plane. A parametric analysis was also conducted by varying the slot ring's dimensions and tuning varactors are shown to vary the ground plane's resonant frequency.

EBG Antenna for GPR Colocated With a Metal Detector for Landmine Detection

Electromagnetic band-gap (EBG) antennas are ideal for handheld sensing applications, such as ground-penetrating radar (GPR) for landmine detection, because of their small size, efficiency, and directivity. Increased detection performance has been shown when a GPR is combined with a metal detector, but a typical EBG antenna would preclude the sensors from being colocated because of the large amount of metal in the EBG structure. An EBG composed of very thin metal is proposed in this letter for application as a GPR colocated with a metal detector, without causing a significant self-response in the metal detector. Manufacturing methods are discussed, and GPR measurements are shown from the thin-metal EBG antennas. The metal detector response from a thin metal sheet is discussed, and measurements of the EBG ground planes are shown using a laboratory wideband electromagnetic induction system. The response from the thin metal is shown to be as low as three orders of magnitude less than from a copper sheet at typical metal detector frequencies.

A Method for Determining Optimal EBG Reflection Phase for Low Profile Dipole Antennas

An analytical method for determining the optimal reflection phase of an electromagnetic band gap (EBG) ground plane to match a low profile dipole antenna is introduced. Image theory is used to incorporate the near field coupling between a dipole antenna and the ground plane. The main contribution of this paper is to show that the optimal EBG reflection phase can be determined at discrete frequencies where a theoretically perfect return loss occurs. The optimal reflection phase is then obtained over a wider frequency band of interest and is related to the antenna's return loss for a given feed impedance and antenna height above the EBG. The resulting reflection phase can be used as a reference for designing an EBG ground plane that is well matched to the antenna without time consuming iterative full wave numerical simulations. Numerical modeling results are compared to the optimal return loss derived from the analytical method to validate the design process. It is also shown that, for certain antennas, vias are not always necessary in the construction of the EBG, which eases the manufacturing process. Finally, a dipole and EBG are constructed using the optimal design method and measurements are compared to the simulations.

Performance enhancement of a circularly polarized patch antenna for radio frequency identification readers using an electromagnetic band-gap ground plane

A miniaturized circularly polarized (CP) patch antenna with wide impedance matching and axial ratio bandwidths and a good efficiency using an electromagnetic band gap (EBG) ground plane is presented. CP is obtained with the truncated corners technique applied on a square patch and size reduction of this radiating element is based on the slow wave phenomenon created in the EBG structure. This antenna is fabricated on a 117 × 117 × 4 mm3 FR-4 substrate (eT = 4.4 and tan δ = 0.22) and dedicated to the European UHF radio frequency identification band (865–868 MHz). The measured bandwidth, realized gain, and total efficiency are 14.4%, 3.7 dBi, and 79%, respectively. Experimental and theorical results are presented and discussed. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1599–1602, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27642

Compact multiband printed-IFA on electromagnetic band-gap structures ground plane

Fourth mobile generation requiring of multistandard operating handsets of small physical size as well as increasing demand for higher data rates.Compact multiband printed inverted-F antennas (IFA) for available wireless communications are proposed in this article. New design of printed IFA based on uniplanar compact electromagnetic band gap (EBG) concept is proposed. A printed-IFA with L-loaded shaped over artificial ground plane is designed as the main antenna to cover the GSM, LTE, UMTS, Bluetooth, and WLAN. The multiband is created by means of an EBG structure that is used as a ground plane. Different shapes of uniplanar EBG as ring, split ring resonator, and spiral rather than mushroom-like structure are investigated. The proposed antenna is built on the uniplanar EBG ground plane with size of 35 × 45 mm2, which is suitable for most of the mobile devices. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1670–1676, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27633

Compact multiband printed-IFA on electromagnetic band-gap structures for wireless applications

Fourth generation mobiles require multi-standard operating handsets with small physical size as well as increasing demand for higher data rates. Compact multi-band printed inverted-F antennas (IFA) for available wireless communications are proposed in this paper. New design of printed IFA based on uniplanar compact electromagnetic band-gap (EBG) structure concept is proposed. A printed-IFA with L-load shaped over an artificial ground plane is designed as the main antenna to cover most wireless applications such as GSM, LTE, UMTS, Bluetooth, Wimax, and WLAN. The multi-band is created by means of an EBG structure that is used as a ground plane. Different shapes of uniplanar EBG such as ring, split ring resonator, and spiral rather than mushroom-like structure are investigated. The proposed antenna is built on the uniplanar EBG ground plane with size of 35 × 45 mm2, which is suitable for most of the mobile devices.

Compact Multiband Printed IFA on Electromagnetic Band-Gap Structures Ground Plane for Wireless Applications

The fourth mobile generation requires of multistandard operating handsets of small physical size as well as has an increasing demand for higher data rates. Compact multiband printed inverted-F antennas (IFAs) for available wireless communications are proposed in this paper. A new design of a printed IFA based on a uniplanar compact EBG concept is proposed. An L-loaded printed IFA shaped over an artificial ground plane is designed as the main antenna to cover the GSM, LTE, UMTS, bluetooth, and WLAN. The multi-band is created by means of an electromagnetic band-gap (EBG) structure that is used as a ground plane. Different shapes of uniplanar EBG as ring, split ring resonator, and a spiral rather than mushroom-like structure are investigated. The proposed antenna is built on the uniplanar EBG ground plane with a size of 35×45 mm2, which is suitable for most of the mobile devices.