Electromagnetic Band Gap Ground Plane Research Articles

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.

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.

Modification of the Radiation Patterns of Higher Order Modes of Triangular Printed Antennas by EBG Ground Planes

The effect of an electromagnetic band-gap (EBG) ground plane on the far-field of the higher order modes of printed antennas, is presented. The performance of the second- and third-order mode of a pair of triangular printed patches with and without an EBG ground plane was studied. It was proved that when the resonance frequency of the EBG is equal or very close to the resonance frequency of one of the higher modes, the entire structure produces fields of high directivity level, with maximum at the broadside and an almost uniform distribution in an area around this direction, which is wider than that produced by the first mode. Therefore, the antenna would operate as a dual-frequency band radiator with similar radiation patterns.

Design of a Dual-Band, Compact Yagi Antenna Over an EBG Ground Plane

A two-element, closely spaced, compact Yagi antenna over an electromagnetic bandgap (EBG) ground plane was designed to provide dual bands. The lower band is generated by the driver element of the Yagi over the EBG ground plane out of the reflection phase band (driver mode). The higher band is attained due to the overall Yagi over the EBG ground plane in the reflection phase band (Yagi mode). The measured realized gains toward the director direction in the driver and Yagi modes are 6.6 and 8.0 dB, respectively.

Design of a broadband dipole in close proximity to an EBG ground plane

One of the known advantages of an electromagnetic bandgap (EBG) ground plane is the fact that a straight-wire dipole can be located parallel and in very close proximity to the ground plane. For such a structure and geometry, a reasonable impedance match to 50 n) can be achieved with more bandwidth than when the dipole is located in close proximity to a PEC ground plane. However, in addition to impedance, radiation-pattern properties must be considered when evaluating the antenna's overall performance and usable bandwidth. Here, we consider the performance properties of a folded bowtie dipole element in close proximity to an EBG ground plane, with emphasis on examining the bandwidth and pattern characteristics. We demonstrate that a dipole element can be designed to exhibit a matched input impedance over approximately a 1.4:1 bandwidth with respect to a 50 n characteristic impedance, when located in close proximity to the EBG ground plane. While the shape of the radiation pattern of the antenna remains relatively unchanged over much of this operating bandwidth, we show that the usable bandwidth of the antenna-EBG combination is limited to approximately 1.5:1, due to pattern degradation at both the lower and upper frequencies. Details of the design approach and feed structure used to match the impedance of the dipole to 50 fl are discussed. Finally, we show that with this element design, the reflection phase bandwidth of the EBG ground plan-e does not limit the matched impedance bandwidth of the antenna. A -portion of ,t ,he work detailed here was presented at the 2005 Antenna Applications Symposium.

EBG(Electromagnetic Band-Gap) 접지면을 갖는 개선된 U-Slotted 패치 안테나의 설계

이동 통신용 안테나로 PEC(Perfect Electric Conductor) 접지면을 갖는 U-slotted 패치 안테나가 널리 이용되고 있으나, 이동 통신 능력을 확대하기 위하여 대역폭의 개선이 요구되어 왔다. 본 논문에서는 대역폭을 확대하기 위하여 EBG(Electromagnetic Band-Gap) 접지면을 갖는 U-slotted 패치 안테나를 제안하고, 그 복사 특성을 고찰하였다. 본 논문에서 제안한 EBG 접지면을 갖는 U-slotted 패치 안테나의 대역폭이 개선됨을 보이기 위하여 EBG와 PEC 접지면을 갖는 두 가지 형태의 U-slotted 패치 안테나를 설계 제작하고 복사 특성을 측정하였다. 측정결과, EBG 접지면을 갖는 U-slotted 패치 안테나가 PEC 접지면을 갖는 안테나보다 대역폭이 넓은 것으로 확인되었다. Generally U-slotted patch antenna with PEC(Perfect Electric Conductor) ground plane is used for mobile telecommunication. However the improvement of the bandwidth is required to enlarge the capability of mobile telecommunication, In this paper, U-slotted patch antenna with EBG(Electromagnetic Band-Gap) ground plane is proposed to enlarge thr bandwidth and its radiation characteristics are investigated. To conform the bandwidth improvement, two kinds of U-slotted patch antennas with EBG and PEC ground plane are designed, fabricated, and radiation characteristics are measured. It is shown that the proposed antenna is wider than U-slotted patch antenna with PEC ground plane in bandwidth.

Design of Three-layer Circular Mushroom-like EBG Structures

In this paper two types of three-layer mushroom-like electromagnetic band-gap (EBG) surfaces with circular patches are investigated. One of them consists of a square array of circular patches and the other one consists of a triangular array of circular patches in upper and lower layers. Guidelines for designing a ground plane for low proflle antenna applications are presented using the re∞ection phase characteristics. The efiect of some parameters of the three-layer structures on the re∞ection phase characteristic is studied. The frequency band in which a wire antenna adjacent to the three-layer EBG surface has good matching is determined by investigating the re∞ection phase characteristics of the EBG ground plane.

Improving microstrip patch antenna performance using EBG substrates

Microstrip patch antennas mounted over a high impedance electromagnetic bandgap (EBG) substrate are studied. The structure is equivalent to a new microstrip antenna, where the conducting ground plane is replaced by a high impedance EBG layer. Initially, the bandgap of the EBG structure is determined. Then, patch antennas with this EBG ground plane are designed to work within and outside the bandgaps. Parametric studies are conducted to maximise their impedance bandwidths and gains. It is found that very wide bandwidths, of around 25%, can be obtained by variation of the original antenna and EBG parameters. Their gains are similarly increased. Sample antennas are also fabricated and tested, to verify the designs.

The performance properties and limitations of antenna elements spaced closely to PEC, PMC and electromagnetic bandgap ground planes

The performance properties and limitations of antenna elements spaced closely to PEC, PMC and electromagnetic bandgap ground planes