Dual-Band EBG Integrated Monopole Antenna Deploying Fractal Geometry for Wearable Applications
TL;DR: In this article, a dual-band wearable fractal-based monopole patch antenna integrated with an electromagnetic band-gap (EBG) structure is presented for the GSM-1800 MHz and ISM-2.45 GHz bands.
Abstract: This letter presents the design of a dual-band wearable fractal-based monopole patch antenna integrated with an electromagnetic band-gap (EBG) structure. The prototype covers the GSM-1800 MHz and ISM-2.45 GHz bands. The EBG structure reduces the radiation into the human body over 15 dB. It also reduces the effect of frequency detuning due to the human body. The performance of the antenna under bending, crumpling, and on-body conditions has been studied and presented. Specific absorption rate (SAR) assessment has also been performed to validate the antenna for its usefulness in wearable applications.
Citations
More filters
TL;DR: In this article, a low-profile wearable antenna is presented for on-body wireless body area network (WBAN) applications, which combines the Koch fractal geometry, meandering slits, and defected ground structure to achieve a novel hybrid structure with compact footprint, good structural conformability, and enhanced impedance bandwidth.
Abstract: A compact and low-profile wearable antenna is presented for on-body wireless body area network (WBAN) applications. The proposed triangular patch antenna is designed using low-cost widely available vinyl polymer-based flexible substrate. The final antenna topology is obtained by the combination of the Koch fractal geometry, meandering slits, and defected ground structure, to achieve a novel hybrid structure with compact footprint, good structural conformability, and enhanced impedance bandwidth (BW) to operate in the Industrial, Scientific, and Medical band with center frequency at 2.45 GHz. The fabricated prototype of the antenna has shown a good agreement between numerical and experimental results. In comparison to state-of-the-art prototypes, our design has more compact form factor of 0.318λo × 0.318λo × 0.004λo, along with 7.75% impedance BW, a peak gain of 2.06 dBi, and overall radiated efficiency of 75%. For the assessment of a specific absorption rate (SAR) performance of our design, it is tested on realistic heterogeneous HUGO voxel model. Both numerical and experimental investigations revealed extremely good robustness to both human body loading and structural deformation, making it an ideal candidate for flexible and body-worn devices.
179 citations
TL;DR: Recent innovative methods in back radiations reduction techniques, circular polarization (CP) generation methods, dual polarization techniques, and providing additional robustness against environmental effects are presented.
Abstract: Wearable antennas have gained much attention in recent years due to their attractive features and possibilities in enabling lightweight, flexible, low cost, and portable wireless communication and sensing. Such antennas need to be conformal when used on different parts of the human body, thus need to be implemented using flexible materials and designed in a low profile structure. Ultimately, these antennas need to be capable of operating with minimum degradation in proximity to the human body. Such requirements render the design of wearable antennas challenging, especially when considering aspects such as their size compactness, effects of structural deformation and coupling to the body, and fabrication complexity and accuracy. Despite slight variations in severity according to applications, most of these issues exist in the context of body-worn implementation. This review aims to present different challenges and issues in designing wearable antennas, their material selection, and fabrication techniques. More importantly, recent innovative methods in back radiations reduction techniques, circular polarization (CP) generation methods, dual polarization techniques, and providing additional robustness against environmental effects are first presented. This is followed by a discussion of innovative features and their respective methods in alleviating these issues recently proposed by the scientific community researching in this field.
174 citations
Cites background from "Dual-Band EBG Integrated Monopole A..."
...Meanwhile, a dual band fractal based monopole antenna was proposed in [106]....
[...]
TL;DR: A wearable circular ring slot antenna with electromagnetic bandgap (EBG) structure for wireless body area network application is proposed in this paper, where the volume of the EBG element is miniaturized for wearable applications.
Abstract: A wearable circular ring slot antenna with electromagnetic bandgap (EBG) structure for wireless body area network application is proposed in this letter. According to the analysis of equivalent circuit model, the volume of the EBG element is miniaturized for wearable applications. The measured impedance bandwidth of the proposed antenna is observed to be 2.28–2.64 GHz, which covers the 2.4 GHz Industrial Scientific Medical (ISM) band. The measured half-power beamwidths are 60° and 54° in the H -plane and the E -plane, respectively, and the front-to-back ratios are 17 and 13 dB in the H -plane and the E -plane, respectively. The specific absorption rate calculated values for tissue in 1 g (for the U.S. standard) and 10 g (for Europe standard) are both less than the limitations. In conclusion, it is proper to use the proposed antenna in wearable applications.
161 citations
Cites background from "Dual-Band EBG Integrated Monopole A..."
...In [10], EBG elements, which are made of copper sheet material, are difficult to integrate into clothes....
[...]
TL;DR: In this article, a compact wearable antenna with a novel miniaturized electromagnetic bandgap (EBG) structure at 2.4 GHz for medical application is presented, which demonstrates a robust, compact, and low-profile solution to meet the requirements of wearable applications.
Abstract: A compact wearable antenna with a novel miniaturized electromagnetic bandgap (EBG) structure at 2.4 GHz for medical application is presented in this letter. The design demonstrates a robust, compact, and low-profile solution to meet the requirements of wearable applications. The EBG structure reduces the back radiation and the impact of frequency detuning due to the high losses of human body. In addition, the structure improves the front-to-back ratio (FBR) by 15.5 dB. The proposed compact antenna with dimensions of ${\text{46}}\,\times \,{\text{46}}\,\times \,{\text{2.4 mm}}^{3}$ yields an impedance bandwidth of 27% (2.17–2.83 GHz), with a gain enhancement of 7.8 dBi and more than 95% reduction in the specific absorption rate. Therefore, the antenna is a promising candidate for integration into wearable devices applied in various domains, specifically biomedical technology.
148 citations
Cites background from "Dual-Band EBG Integrated Monopole A..."
...4 GHz have been reported in [9], [10], [12], and [13]....
[...]
...From the figure, it can be observed that removing the EBG structure causes the shifting of the resonant frequency to the lower band due to the high dielectric nature of human tissue that also influences the response of the antenna, which results in the attenuation and detuning [9]....
[...]
TL;DR: In this paper, a planar monopole with a 2 × 1 array of electromagnetic bandgap (EBG) structures is proposed for wearable applications, where the shape of the unit cell and the gap between the ground and the EBG layer are adjusted so that the antenna operates at 2.45 GHz.
Abstract: This paper presents a planar monopole backed with a 2 × 1 array of electromagnetic bandgap (EBG) structures. The reflection phase of a single EBG unit cell has been studied and exploited toward efficient radiation of a planar monopole antenna, intended for wearable applications. The shape of the EBG unit cell and the gap between the ground and the EBG layer are adjusted so that the antenna operates at 2.45 GHz. The proposed antenna retains its impedance matching when placed directly upon a living human subject with an impedance bandwidth of 5%, while it exhibits a measured gain of 6.88 dBi. A novel equivalent array model is presented to qualitatively explain the reported radiation mechanism of the EBG-backed monopole. The proposed antenna is fabricated on a 68 × 38 × 1.57 mm
3
board of semiflexible RT/duroid 5880 substrate. Detailed analysis and measurements are presented for various cases when the antenna is subjected to structural deformation and human body loading, and in all cases, the EBG-backed monopole antenna retains its high performance. The reported efficient and robust radiation performance with very low specific absorption rate, compact size, and high gain make the proposed antenna a superior candidate for most wearable applications used for off-body communication.
142 citations
Cites result from "Dual-Band EBG Integrated Monopole A..."
...Overall, the proposed antenna performance has been shown to be robust to structural deformation along both the x- and y-axes and is compared favorably to several previously reported designs where degradation in impedance matching and/or significant band shifting were observed [24], [34]–[37]....
[...]
...Similar conclusions have been drawn in [37]....
[...]
References
More filters
TL;DR: Fractal antenna engineering has been primarily focused in two areas: the first deals with the analysis and design of fractal antenna elements, and the second concerns the application of Fractal concepts to the design of antenna arrays as discussed by the authors.
Abstract: Recent efforts by several researchers around the world to combine fractal geometry with electromagnetic theory have led to a plethora of new and innovative antenna designs. In this report, we provide a comprehensive overview of recent developments in the rapidly growing field of fractal antenna engineering. Fractal antenna engineering research has been primarily focused in two areas: the first deals with the analysis and design of fractal antenna elements, and the second concerns the application of fractal concepts to the design of antenna arrays. Fractals have no characteristic size, and are generally composed of many copies of themselves at different scales. These unique properties of fractals have been exploited in order to develop a new class of antenna-element designs that are multi-band and/or compact in size. On the other hand, fractal arrays are a subset of thinned arrays, and have been shown to possess several highly desirable properties, including multi-band performance, low sidelobe levels, and the ability to develop rapid beamforming algorithms based on the recursive nature of fractals. Fractal elements and arrays are also ideal candidates for use in reconfigurable systems. Finally, we provide a brief summary of recent work in the related area of fractal frequency-selective surfaces.
1,055 citations
TL;DR: In this article, a dual-band coplanar patch antenna integrated with an electromagnetic band gap substrate is described, where the antenna structure is made from common clothing fabrics and operates at the 2.45 and 5 GHz bands.
Abstract: Performance of a dual-band coplanar patch antenna integrated with an electromagnetic band gap substrate is described. The antenna structure is made from common clothing fabrics and operates at the 2.45 and 5 GHz wireless bands. The design of the coplanar antenna, band gap substrate, and their integration is presented. The band gap array consists of just 3 times 3 elements but reduces radiation into the body by over 10 dB and improves the antenna gain by 3 dB. The performance of the antenna under bending conditions and when placed on the human body are presented.
599 citations
"Dual-Band EBG Integrated Monopole A..." refers background or methods in this paper
...Bending and crumpling measurements have to be performed to validate the wearable antenna as in [4], [7], and [10]....
[...]
...For bending analysis, a foam cylinder of 140 mm diameter, corresponding to the approximate size of a human leg [7], has been modeled....
[...]
...In [7], a dual-band co-planar patch antenna is integrated with an electromagnetic band-gap structure....
[...]
TL;DR: Experimental and numerical results show that the radiation characteristics, impedance matching, and SAR values of the proposed design are significantly improved compared to conventional monopole and dipole antennas, which makes it a good candidate for the wearable telemedicine application.
Abstract: We present a flexible, compact antenna system intended for telemedicine applications. The design is based on an M-shaped printed monopole antenna operating in the Industrial, Scientific, and Medical (ISM) 2.45 GHz band integrated with a miniaturized slotted Jerusalem Cross (JC) Artificial Magnetic Conductor (AMC) ground plane. The AMC ground plane is utilized to isolate the user's body from undesired electromagnetic radiation in addition to minimizing the antenna's impedance mismatch caused by the proximity to human tissues. Specific Absorption Rate (SAR) is analyzed using a numerical human body model (HUGO) to assess the feasibility of the proposed design. The antenna expresses 18% impedance bandwidth; moreover, the inclusion of the AMC ground plane increases the front to back ratio by 8 dB, provides 3.7 dB increase in gain, in addition to 64% reduction in SAR. Experimental and numerical results show that the radiation characteristics, impedance matching, and SAR values of the proposed design are significantly improved compared to conventional monopole and dipole antennas. Furthermore, it offers a compact and flexible solution which makes it a good candidate for the wearable telemedicine application.
349 citations
"Dual-Band EBG Integrated Monopole A..." refers background in this paper
...In [5], anM-shaped printed monopole antenna for operating in the ISM-2....
[...]
TL;DR: A novel approach to measure the dielectric constant of fabric substrate materials used for the development of wearable antennas (also called textile antennas) is presented, based on the resonance method, and shows superior performance characteristics compared to others, indicating the correctness of the approach.
Abstract: A novel approach to measure the dielectric constant of fabric substrate materials used for the development of wearable antennas (also called textile antennas) is presented in this paper. The technique reported here is based on the resonance method and focused on the use of microstrip patch radiator, which contains fabric material as its substrate. The accurate value of the dielectric constant of the fabric material can easily be extracted from the measured resonant frequency of the patch radiator. The dielectric constant values of six fabric materials, including jeans cotton, polyester combined cotton, and polyester, have been determined by this way. As an extended objective of this paper, initial investigations are done to study the performance/behavioral characteristics of wearable antennas in the Bluetooth industrial, scientific, and medical band. Two of the six textile antenna structures, developed to meet out the primary objective of determining the dielectric constant of fabrics, are tested, and their performance characteristics, such as impedance bandwidth, gain, efficiency, etc., are measured. In addition, another Bluetooth antenna employing polyester fabric substrate is designed considering its measured accurate value of dielectric constant and subjected to radiation pattern measurements. In general, all the measured antennas yield very good results, fulfilling the requirements for practical applications, and in particular, the third fabric antenna utilizing the accurate value of the dielectric constant determined shows superior performance characteristics compared to others, indicating the correctness of our approach. Thus, the suitability of fabric substrate materials for the development of textile antennas with microstrip patch configuration is also well demonstrated.
229 citations
"Dual-Band EBG Integrated Monopole A..." refers background in this paper
...Extensive research has been carried out for the usage of several fabrics and polymers as substrate materials for the above said applications, [1], [2]....
[...]
01 Nov 2006
TL;DR: How the performance of wearable textile antennas is affected on the antenna bending is described herein and the results are given for a conventional patch, EBG, and dual-band U-slot antennas.
Abstract: This paper describes how the performance of wearable textile antennas is affected on the antenna bending. Here, we will focus on the resonance frequency fluctuation and input-match bandwidth variation due to the antenna bending. The results are given for three different antennas, namely, a conventional patch, EBG, and dual-band U-slot antennas.
157 citations
"Dual-Band EBG Integrated Monopole A..." refers background or methods in this paper
...The prototype provides improved bandwidth performance in both the bands compared to literature with similar application [4]....
[...]
...In [4], electromagnetic band-gap (EBG) layer has been designed beneath the antenna for performance enhancement (reduction of detuning effects)....
[...]
...Bending and crumpling measurements have to be performed to validate the wearable antenna as in [4], [7], and [10]....
[...]
...The prototype provides stable reflection coefficient characteristics for bending analysis compared to [2], [4], and [11]....
[...]