Surface Wave Losses Research Articles

CSRR and EBG loaded wideband THz dielectric resonator MIMO antenna for nano communication and bio-sensing applications

In this paper, a wideband Graphene-inspired dielectric resonator THz MIMO antenna is designed. The antenna has dimensions of 56 × 56 × 3.6 μm³ and is designed on a Rogers RO3035 substrate with a relative permittivity of 3.6 and loss tangent of 0.0015. This antenna works in the range of 6.0 THz-12.5 THz (70.76 %) with a peak gain of 7.68 dBi and radiation efficiency (>70 %) is suitable for use in medical imaging and THz wireless near-field applications. A CSRR is loaded to obtain band notch characteristic for avoiding interference between nearby wireless devices in the range of 10.6–10.8 THz. EBG was also introduced with a patch antenna to reduce surface wave loss and improve isolation, resulting in a high front-to-back ratio (FBR) in the range of 10–12.5 THz. Without the graphene disk, the silicon-based DRA did not achieve significant gain. At a chemical potential of 0.5 eV and a relaxation time of 0.1 ps, the proposed DRA demonstrated good antenna properties. By varying the chemical potential and relaxation time, frequency agility was easily achieved. A Graphene disk having a height of 3 μm is placed on a Silicon (εr = 11.1) based cylindrical DRA to provide high gain and improve the impedance bandwidth, achieving wide bandwidth from 6.0 THz to 12.5 THz. The proposed two element antenna performance is evaluated by parameters such as gain, return loss, isolation between two antenna elements, and diversity parameters like Envelope correlation coefficient ECC<0.1, Directive Gain >9.5 dB, Total Active reflection Coefficient >10 dB and Avg. Channel capacity loss <0.35bps/Hz so that the proposed antenna is suitable for wideband nano/optical communication in IoT-6G. Furthermore, the antenna is suitable for biological sensing applications due to its average sensitivity and FOM for hemoglobin and urine of 805.33GHz/RIU and 805.55GHz/RIU, respectively, and 3.37 and 10.55.

Design of UWB Wearable Conformal Antenna for Body Area Networks

In this paper, a wearable ultra-wideband (UWB) micro-strip antenna is designed to meet the demand for Wireless Body Area Network (WBAN). This is a wearable textile antenna, which was formed on a jeans fabric substrate to reduce surface-wave losses. The single-fed circular strip monopole antenna provides good impedance matching over the entire UWB frequency range of 2.9∼10.6 GHz. The dielectric constant εr 2.2, and the loss tangent tan δ 0.04 of the jean substrates are measured by using the coaxial ring method. The proposed antenna consists of an improved circular radiation patch with the defective ground structure to expand the frequency band of the antenna and improve the radiation characteristics of the antenna with small dimensions of 20 × 30 × 1.4 mm3. In addition, structural deformation of the proposed antenna is performed to analyze the flexibility of the proposed antenna. The simulated SAR values follow the FCC limit, making it most suitable for wearable applications. Key Words: Antenna, S-Parameters, Far Field Directivity, Applications of Antenna, HFSS.

Simulation of Wearable Microstrip Patch Antenna by Using Textile Material for Ambient RF Energy Harvesting

Future enhancements in radio frequency (RF) energy harvesting technology will make easy the creation of a network with no need of dedicated transmitters, as a reliable source of wireless energy power. Recently, the development and employment of wearable antennas has increased rapidly for application in the miniaturization of wireless communication devices. The principal feature of wearable antennas is that they are designed as garment elements able to transmit or receive wireless signals. In this context, we propose a design of a wearable textile microstrip patch antenna operating for wireless body area network (WBAN)at the resonance frequency =2.40GHz. The microstrip patch antenna with an edge feeding technique is designed and simulated by using the Keysight Advanced Design System (ADS) software. Textile materials have a low dielectric constant that reduces the surface wave losses and increases the impedance bandwidth of the antenna. The chosen dielectric substrate in this work is the jeans fabric with relative permittivity of 1.70, thickness of 1.00 mm and dissipation factor of 0.025. The antenna performance parameters are obtained from ADS Momentum. Simulation results show that antenna has the gain of 3.22 dBi and directivity of 8.10 dBi, showing that the wearable textile microstrip antenna has a good performance.

Flexible and Small Textile Antenna for UWB Wireless Body Area Network

In this paper, a miniaturized textile microstrip antenna is proposed for wireless body area networks (WBAN). The ultra-wideband (UWB) antenna used a denim substrate to reduce the surface wave losses. The monopole antenna consists of a modified circular radiation patch and an asymmetric defected ground structure, which expands impedance bandwidth (BW) and improves the radiation patterns of the antenna with a small size of 20 × 30 × 1.4 mm3. An impedance BW of 110% (2.85–9.81 GHz) frequency boundaries was observed. Based on the measured results, a peak gain of 3.28 dBi was analyzed at 6 GHz. The SAR values were calculated to observe the radiation effects, and the SAR values obtained from the simulation at 4/6/8 GHz frequencies followed the FCC guideline. Compared to typical wearable miniaturized antennas, the antenna size is reduced by 62.5%. The proposed antenna has good performance and can be integrated on a peaked cap as a wearable antenna for indoor positioning systems.

Graphene based microstrip patch antenna on photonic crystal substrate for 5G application

One of the strongest and thinnest substances known to exist is graphene. It can be efficiently used for antenna fabrication and significant benefits can be analyzed such as size miniaturization, gain and return loss enhancement, flexibility and increase in bandwidth, etc. In this paper, a graphene patch antenna has been designed and fabricated for 5G applications at 28.3 GHz. Different 5G frequency allocation throughout the world is shown in tabular form. Photonic crystal substrate is used to reduce surface wave loss which in turn, increases the radiation efficiency of the antenna. The ground plane is made up of copper, treated as a Perfect Electric Conductor Several unique properties of graphene are analyzed and shown. Then, a thin graphene sheet is used as a patch and an antenna is designed and fabricated. The patch has dimensions of 3.4 mm by 2.38 mm. The simulated return loss is maximum at −33.69 dB at 28.3 GHz, whereas for the measured design it is −26.31 dB at 28.04 GHz. It is observed that graphene can be a good alternative to existing conductors, especially at higher frequencies. The proposed antenna is designed and simulated using HFSS software.

Computationally Efficient Surrogate-Assisted Design of Pyramidal-Shaped 3-D Reflectarray Antennas

Reflectarrays (RAs) have been attracting considerable interest in recent years due to their appealing features, in particular, the possibility of realizing pencil-beam radiation patterns, as in the phased arrays, but without the necessity of incorporating the feeding networks. These characteristics make them attractive solutions, among others, for satellite communications or mobile radar antennas. Notwithstanding, available microstrip implementations are inherently narrow-band and heavily affected by conductor and surface wave losses. RAs based on grounded dielectric layers offer improved performance and flexibility in terms of shaping the phase reflection response. In either case, a large number of variables (induced by the need for independent adjustment of individual unit cell geometries) and the necessity of handling several requirements make the design process of reflectarrays a challenging endeavor. In particular, RA optimization is extremely expensive when conducted at the level of electromagnetic (EM) simulation models, otherwise necessary to ensure reliability. A practical solution is a surrogate-assisted design with the metamodels constructed for the RA unit elements. Unfortunately, conventional modeling methods require large numbers of training data samples to render accurate surrogates, which turns detrimental to the optimization process efficiency. This work proposes an alternative approach with the unit element representations constructed using deep learning with automated adjustment of the model architecture. As a result, design-ready surrogates can be constructed using only a few hundred samples, and the total RA optimization cost is reduced to only a handful of equivalent EM analyses of the entire array. Our approach is validated using an RA incorporating 3-D pyramidal-shaped elements and favorably compared to benchmark techniques. Experimental verification of the obtained design is discussed as well.

Design of UWB Wearable Conformal Antenna Based on Jean Material

In this paper, a wearable ultra-wideband (UWB) microstrip antenna is designed to meet the demand for Wireless Body Area Network (WBAN). This is a wearable textile antenna, which was formed on a jeans fabric substrate to reduce surface-wave losses. The single-fed circular strip monopole antenna provides good impedance matching over the entire UWB frequency range of 2.9∼10.6 GHz. The dielectric constant ε r = 2.2, and the loss tangent tan δ = 0.04 of the jean substrates are measured by using the coaxial ring method. The proposed antenna consists of an improved circular radiation patch with the defective ground structure to expand the frequency band of the antenna and improve the radiation characteristics of the antenna with small dimensions of 20 × 30 × 1.4 mm 3 . In addition, structural deformation of the proposed antenna is performed to analyze the flexibility of the proposed antenna. The simulated SAR values follow the FCC limit, making it most suitable for wearable applications.

Design of Wearable Textile Patch Antenna Using C-Shape Etching Slot

With today's advanced technology microstrip patch antennas are more flexible and stronger than ever before. These antennas can work on various frequencies ranging from low to high for a huge variety of applications including medical, military and quite a few more. This paper presents the textile antennas those are designed for Wi-MAX application with the frequency range of 3.09–3.94 GHz, fifth generation (5G) lower band with the resonant frequency of 4.23–5.65 GHz and UWB 4.62–10.74 GHz applications. This work also introducing a single C-shape etching slot (CSES) in a rectangular patch antenna. The textile substrate (jeans) has been applied to reduce the surface wave losses and design a wearable textile antenna using microstrip line feed technology. Bending effect up to 750 and radiation effect on human tissue as specific absorption rate (SAR) are analyzed using Computer Simulation Technology (CST) tools. Textile antennas for multiple band applications can be created using CSES which can be attributed to cotton, denim cotton and polyester.

Efficiency enhancement techniques of microwave and millimeter‐wave antennas for 5G communication: A survey

AbstractEfficiency is a critical antenna parameter that describes how well an antenna emits and accepts electromagnetic signals. When an antenna has poor efficiency, the input power is only partially radiated and is primarily wasted due to internal losses such as conduction, dielectric, mismatching, and several other losses within the antenna. In order to enhance signal quality, a communication system requires an antenna with high efficiency and gain. The fifth‐generation wireless system will use millimeter wave spectrum along with sub 1 GHz and sub 6 GHz bands to fulfill wide bandwidth, ultra‐high‐speed, and low latency requirements of 5G communication. Compact low‐profile antenna with high radiation efficiency, high gain, and wideband characteristics are required to support bandwidth requirements of 5G and mitigate the signal degradation due to high link losses caused by environmental absorptions at the millimeter‐wave (mm‐wave) spectrum. Compact planar antennas have become an important part of modern wireless communication equipment, but these antennas are associated with many issues like low efficiency, poor gain, small radiation resistance, and high cross‐polarization, which is due to the increased conductor and dielectric losses, surface wave losses and so forth. Various techniques need to be employed for the improvement of the efficiency of the antenna, which results in high gain low loss antenna characteristics. This article presents the survey of various efficiency enhancement techniques for 5G antennas and a review of structures that provides good radiation efficiency for 5G communications.

Impact of EBG on Microstrip Patch Antenna

The correct use of electromagnetic band structures (EBG) becomes very interesting in the field of electromagnetic theory and antenna design. The use of electromagnetic band- gap (EBG) structures constructed with microstrip technology is one of the efficient techniques to reduce interconnection problems. This article proposes a three-layer dielectric substrate with four holes or air cylinders forming an EBG structure with an insert feed technique. Here the idea is to use the specified structure in the mid layer of dielectrics. In order to improve over surface wave losses, the necessity of introducing EBG structures is appeared. The achievement of higher efficiency and enhanced bandwidth is feasible by proper impedance matching during the feeding mechanism. The structure is designed for the resonant frequency of 2.4 GHz and the entire simulation is performed with Ansoft High Frequency Structure Simulator (HFSS) version 11.

Cross-Shaped Interconnected Receiver–Transmitter Metasurface for a Circularly Polarized Fabry–Pérot Antenna

In this paper, we proposed a cross-shaped interconnected receiver–transmitter (RT) metasurface (MS) that was employed for a high-aperture-efficiency, high-gain, circularly polarized Fabry–Pérot (FP) antenna. The RT-MS unit cell consists of upper-layer cross-shaped patch and lower-layer squared patch that are connected by two metal-probes that cross the sandwiched middle metal-plane. The bottom patch receives electromagnetic wave, functioning as receiver, and transfers it to the top cross-shaped patch passing through the two mental probes. Through tuning the relative locations of the two probes, equal amplitude and 90° phase difference can be obtained, thereby achieving linear to circular polarization conversion performance, indicating that the MS has the ability of tuning transmission coefficients independently. Meanwhile, the MS is designed to present high reflectivity that high-gain property is obtained when forming a FP cavity. Then, an off-center coaxial patch antenna is applied as feeder due to its stable radiation performance. To further enhance the performance of the source antenna, an AMC structure is adopted to improving the radiation gain, efficiency and radiation directivity by suppressing surface wave loss. Meanwhile, the profile was also reduced. The linearly polarized wave emitting from the feeder multi-reflected in the FP cavity formed by MS superstrate and AMC structure, and then transmit it in phase to the space, thus a high-gain and CP radiation is achieved as final. The measurements demonstrate that the proposed RT-MS-based antenna perform a maximum gain of 18.7dBic at 9.4GHz with aperture efficiency of 76.7%, and a circular polarization bandwidth within 9.2-9.7GHz, while, the antenna owns a compact size of only <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2.85\lambda _{0}\times 2.85\lambda _{0}$ </tex-math></inline-formula> . Thus, a novel RT-MS-based FP antenna exhibit a good radiation performance that can be a candidate in applying to communication and point-to-point links.

Analytical Calculation of Maximum Radiated Power and Surface Wave Loss of Printed Antennas on Thick Anisotropic Substrates

A new approximation for the Green's function of a grounded anisotropic dielectric slab is proposed to obtain closed-form analytical expressions for the maximum radiated power of a short printed dipole on an anisotropic substrate. The corresponding surface wave power can also be accurately estimated as a root of a cubic polynomial which makes it possible to compute radiation efficiency due to surface wave loss analytically.

Microstrip Antenna Efficiency and Surface Wave Loss

The efficiency components of a rectangular microstrip antenna (MSA) have been traditionally computed using the cavity model. The MSA cavity model does not include surface wave losses, but has been extended to include them. MSA surface wave losses have been assumed to be TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> mode on a shorted dielectric slab, which have no lower cutoff frequency. Here we examine this assumption using full-wave simulation. The nonradiative losses appear inconsistent with the generation of a pure TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> mode.

Design of Circularly Polarized Triple-Band Wearable Textile Antenna with Safe Low SAR for Human Health

In this manuscript, an antenna on textile (jeans) substrate is presented for the WLAN, C band and X/Ku band. This is a wearable textile antenna, which was formed on jeans fabric substrate to reduce surface-wave losses. The proposed antenna design consists of a patch and a defected ground. To energize the wearable textile antenna, a microstrip line feed technique is used in the design. The impedance band width of 23.37% (3.4–4.3 GHz), 56.48% (4.7–8.4 GHz) and 31.14% (10.3–14.1 GHz) frequency bands are observed, respectively. The axial ratio bandwidth (ARBW) of 10.10% (4.7–5.2 GHz), 4.95% (5.9–6.2 GHz) and 10.44% (11.8–13.1 GHz) frequency bands are observed, respectively. A peak gain of 4.85 dBi is analyzed at 4.1-GHz frequency during the measurement. The SAR value was calculated to observe the radiation effect and it was found that its utmost SAR value is 1.8418 W/kg and 1.919 W/kg at 5.2/5.5-GHz frequencies, which is less than 2 W/kg of 10 gm tissue. The parametric study is performed for the validation of the proper functioning of the antenna.

Novel, compact, circular-sectored antenna for Ultra-Wideband (UWB) communications

ABSTRACTThis article presents a compact circular-sectored microstrip antenna embedded with circular slots and a sectoral ground plane for enhanced bandwidth and applicable for UWB communications exhibiting an equivalent Fractional Bandwidth of 156.04% (2.5–20.25 GHz) and allows a compactness of about 79.15% using Rogers RT-Duroid 5880 as a substrate for lesser surface wave loss and attaining broader bandwidth. The gain of the antenna ranges from 1.85 to 6.10 dBi throughout the resonant frequency band and the results obtained from measurement are validated to justify the applicability of this antenna for various WLAN and Wi-MAX frequency bands.

1561 Published By: Blue Eyes Intelligence Engineering &amp; Sciences Publication Retrieval Number: C5858098319 /2020©BEIESP DOI:10.35940/ijrte.C5858.018520 Journal Website: www.ijrte.org Flexible Wearable Antennas for Body Area Network

In recent years, wearable antenna design has grossed research interest amongst academicians and researchers due to its versatile application in body area networks for transmitting/receiving signals in sufficiently large areassuch as ICU, trauma centers in hospitals for biomedical applications at ISM (2.45 GHz) frequency range. A wearable antenna is highly flexible in nature making it popular and demanding. What makes it even more suitable for biomedical applications is its simple design methodology and ease of integrationonpatient's dress/clothes for antenna placement in wireless communication. This paper presents a thorough investigation of various antennadesign methodologies to design a flexible wearable antenna that can be mounted on textile material for body-centric wireless communication. The traditional antenna design uses non-flexible substrate materials (such as FR-4, RT duriod, foam, etc..) having medium to high dielectric constant. This results in generation of surface wave losses which reduces antenna transmission capabilities. Flexible wearable antennas, on the contrary, uses ordinary textile materials used as a substrate whose dielectric constant is very low thereby providingreduced surface wave losses. As wearable antennas are mounted on textile fabrics it is possible to use these antennas to implant them on patients’ bodies(inside/outside on the clothes) for transmitting the patients’ body parameters (such as body temperate, heart rate, etc..) measured using various sensors/transducers. In this paper,a thorough review of different types of substrate materialsused for designing flexible wearable antennas is done.

A Slotted Single Feed Circularly Polarized Microstrip Patch Antenna with Suppressed Surface Wave Losses for WLAN Applications

The circularly polarized microstrip antenna has been of great importance in WLAN applications. A circularly polarized slotted circular patch antenna with co-axial feed geometry has been designed to meet the requirements. The antenna designed has been slotted at several locations to make it radiate circularly polarized radiation. Two metallic cylindrical vias have been inserted near the two diametric ends of the slot to improve the realized gain of the antenna. The antenna structure is resonating at 6.4 GHz with 3dB axial ratio bandwidth of 200MHz and gain of 9.8dB has been observed.

Analytical study and experimental verification of the surface wave loss on a tensor impedance surface

AbstractIn this article, propagation loss is investigated for a surface wave (SW) when enters from a scalar impedance surface (SIS) to a tensor impedance surface (TIS). This loss has two components: (a) loss due to change in the propagation direction and mode transformation of the SW and (b) loss due to the surface impedance mismatch between the SIS and the TIS. First, two analytical methods are presented to calculate the loss and then the methods are verified by a sample structure, which is fabricated with the printed circuit technology at 15.1‐15.75 GHz frequency bandwidth. The calculated total loss for the sample structure is 8.7 dB and 5.6 dB at 15.1 and 15.7 GHz, respectively, which is in good agreement with the measured results.

Magnetostatic Surface Wave Dispersion and Losses in an Yttrium-Iron Garnet Film With a Subwavelength Periodic Structure

Magnetostatic surface wave propagation was measured in an yttrium-iron garnet film with a subwavelength, micrometer-sized, periodic array of etched grooves. There were regions with anomalous dispersion and rejection bands in the frequency dependence of the transmission characteristic. Their number and bandwidth changed depending on the angle between the directions of the bias magnetic field and the grooves.

On-Chip Antenna Integration for Millimeter-Wave Single-Chip FMCW Radar, Providing High Efficiency and Isolation

A complete functional 60-GHz BiCMOS single-chip millimeter-wave frequency-modulated continuous wave (FMCW) radar with on-chip integrated antennas is designed, realized, and experimentally validated. The chip is configured with one transmitting and two receiving antennas. A high antenna efficiency and isolation between the transmitting and receiving antennas is achieved by using a cavity-backed on-chip monopole and by optimizing the package environment. Surface-wave losses and back radiation are reduced, and a high antenna gain is obtained with small ripples in the antenna pattern by implementing special structures on the PCB of the integrated circuit package. The experimental results from the single-chip radar show that the on-chip antennas provide a gain of 2 dBi with very low back radiation. The realized antennas achieve an impedance bandwidth of more than 50% with a corresponding simulated efficiency of 45%. In addition, the proposed approach suppresses surface waves and meets the specific FMCW radar requirements, such as a more than 25-dB isolation between the transmitting and receiving antennas.