Radiation Efficiency Research Articles

Development and analysis of small Multi Input Multi Output antenna with better isolation for Frequency Range‐2 5th Generation band applications

SummaryA simple planar wideband four‐port MIMO antenna of size 2.75𝜆l × 2.75𝜆l × 0.04𝜆l (𝜆l is the wavelength when fl is 24.26 GHz) with high isolation that offers the 24.26 to 30.2 GHz bandwidth covering the 5G FR‐2 spectrums is proposed in this work. Total fractional bandwidth of 21.8% has been achieved that covers the n257 (26.5 to 29.5 GHz), n258 (24.25 to 27.5 GHz), and n261 (27.5 to 28.35 GHz) 5G spectrums. Popular rectangular radiator‐based 4‐port MIMO antenna with symmetric stubs loaded parallel to feed line and tapered semi‐circular cut in the lower corners of patch is incorporated that exhibits an excellent isolation that is below −27 dB through the entire spectrum and the extreme realized separation is −40 dB. The projected MIMO radiator is premeditated on RT/duroid 5880 of 0.508 mm depth and permittivity (εr) of 2.2. The maximum radiation efficiency and gain of the proposed antenna are 93.07% and 6.48 dBi, respectively. The MIMO antenna parameters such as envelope correlation coefficient (ECC) were achieved lesser than 0.003, diversity gain (DG) was achieved around 10 dB, channel capacity loss (CCL) was achieved lower than 0.15 bits/s/Hz, and mean effective gain (MEG) was achieved between −3.6 dB and −3 dB throughout the impedance band, which exhibit the excellent MIMO properties, and thus, the projected antenna is appropriate for 5G/beyond 5G wireless technologies.

Design of Y-shaped tri-band rectangular slot DGS patch antenna at sub-6 GHz frequency range for 5G communication

This paper presents the design and development of a rectangular slot DGS patch antenna fed by a microstrip line, designed to operate across three distinct frequency bands at 4.0 GHz, 4.9 GHz, and 5.5 GHz for 5G wireless communication applications. The antenna design outlined in this study is implemented on a Fr-4 substrate with dimensions measuring 50.5 × 41.12 × 1.5 mm3. The antenna gains at three frequency bands are 2.69 dBi, 7.27 dBi, and 11.37 dBi having impedance bandwidths of 9%, 8.9%, and 5.1%, respectively. The attained bandwidths are 356 MHz, 443 MHz, and 287 MHz for the respective frequency bands. The radiation efficiencies of the proposed antenna are 90%, 82%, and 79% of the three respective frequencies. Antenna 1 in this study exhibits single-band behavior, effectively covering the single frequency band which is 5.5 GHz (5.3578–5.9519 GHz) 5G unlicensed band 5-GHz WLAN IEEE 802.11a frequency. On the other hand, Antenna 2 demonstrates dual-band characteristics spanning the S-band 3.7 GHz (3.5619–3.8544 GHz) and C-band range 5.1 GHz (4.8496–5.2008 GHz) suitable for mid-band 5G applications. Antenna 3 proposed antenna exhibits a tri-band functionality within the C-band spectrum. The results highlight multiple-band operation, consistent high gain, high directivity, and favorable directional radiation patterns.

An elliptical dual-band antenna with crescent slot for 5G mmWave applications

Abstract This paper proposes a new elliptical dual-band antenna with a crescent slot with the advantages of compactness, lightweightness, low cost, and easy installation for 5G mmWave applications. The radiating element is obtained by Boolean manipulation of three ellipses of unequal length to short axis ratio, the resulting crescent slot defining its dual-band characteristics. The -10 dB impedance bandwidth of 23.8—31.6 GHz at 28 GHz and a bandwidth range of 36.8—40.6 GHz at 38 GHz are achieved, completely covering the currently applicable n257, n258, n260 and n261 mmWave bands and filtering out the unlicensed 31—36 GHz band. Dimensions of the single element are 10 mm by 7 mm. In addition, to reduce the interference caused by atmospheric attenuation, a conventional feeder network is combined with the designed antenna element to form a 1 × 4 line array to improve the gain. The antenna array with total dimensions of 20 × 25 mm2 is modeled in 0.254 mm thick Rogers 5880 substrate. As a result of the array configuration, 10.4 dBi gain and a 95% radiation efficiency are achieved in the 28 GHz band. Meanwhile, at the 38GHz band, the gain is 10.4 dBi and the radiation efficiency is 95%. The proposed antenna meets the 5G communication requirements well and can be a better candidate in the mmWave band range.

A compact dielectric resonator antenna with wideband circular polarization characteristics for C and X‐band applications

AbstractA wideband circularly polarized (CP) stacked rectangular dielectric resonator antenna (RDRA) is proposed in this article. The 3 dB axial ratio (AR) and 10 dB impedance bandwidth overlap of more than 66% is obtained. For increased bandwidth, the antenna comprises two dielectric resonators separated by an air gap. The upper dielectric layer is rotated at relative to the lower layer to obtain orthogonal modes for CP Both layers have dielectric constant . The rotation aids excitation of orthogonal modes , and in RDRA. The higher‐order modes generate left‐hand circular polarization at frequencies 6.75, 7.8, and 10.7 GHz, respectively. The upper layer consists of three holes giving a 10 dB impedance bandwidth of 66.7% from 6.52 to 11.02 GHz. The CP gain of 8.7, 6.8, and 6.4 dBi for 6.75, 7.8, and 10.7 GHz, respectively, is measured. The conformal orthogonal feeds enable a 72 3 dB AR bandwidth across the entire frequency band. The radiation efficiency is observed above 89 in the entire band (6.5–11 GHz). This work demonstrates a 66.7 overlap of 10 dB impedance and 3 dB AR bandwidth along with high gain in a single design which is suitable for 5G applications in C‐band as well as other X‐band applications.

Evolution: A quantity–quality trade-off constrains the evolution of immortality in bacterial endospores

Bacterial endospores are extremely resilient cells, capable of withstanding the most dramatic environmental challenges. New work identifies a trade-off between resistance to UV radiation and germination efficiency, a trade-off mediated by an unexpected sporulation 'contingency locus'.

Numerical simulation of premixed n-heptane/air combustion in micro tube with internal channel optimization

In military and aerospace fields, petrol and aviation kerosene are the preferred fuels for micro power systems due to their reduced carrying load and convenient fuel source. Therefore, n-heptane, an alternative to petrol and aviation paraffin, was chosen as the fuel. A micro quartz glass tube was used as the combustor, and the premixed combustion characteristics of n-heptane/air were investigated using numerical simulations. The method used to improve the internal flow channel includes a built-in cross baffle and scaled backward-facing step. The resulting optimized combustion characteristics, such as internal flow line, wall temperature, CO emission, and wall radiation, have been analyzed. The results indicate that, with a fixed equivalence ratio of 1.0 and a n-heptane mass flow rate of 2.70 mg/s, the built-in cross baffle concentrates and stabilizes the high temperature zone of the flame, resulting in a significant increase in wall temperature. Conversely, the use of the micro tube with scaled backward-facing step creates a reflux zone due to the sudden expansion of the inlet cross-section, which promotes better fuel mixing and flame anchoring. Furthermore, after comparing the output efficiencies of micro tube with different internal structures, it was discovered that enhancing the internal channel of the micro tube is crucial for increasing the wall radiation efficiency.

Wideband meander-line-antipodal-vivaldi slot-antenna for millimeter-wave applications

An antipodal Vivaldi monopole radiator is employed in an innovative wideband planar slotted meander antenna. A quarter-wave microstrip feed is coupled to the antenna for a ground reflector plane over a meander line with five right and left antipodal Vivaldi (RLAV) slots on either side and a series of Z, inverted U and inverted Z-shaped turns. The FR4 substrate with a relative permittivity of 4.4 and modest dimensions of 50 × 20 × 1.6 mm3 is used to implement the proposed antenna. A 17.39% fractional bandwidth of -29.10dB (S11 <-10dB), an average radiation efficiency of 73%, and a gain of 6.7dBi at the central frequency of 28GHz. The outcomes of using RLAV arms at the centre of the meander structure enhance the antenna’s performance validated using the high-frequency structural software Ansys 2022R1, which is a finite element method (FEM) tool. The measured results indicate that the bandwidth enhancement has been fine-tuned for use in the 5G millimetre wave band in the Frequency Range 2 (FR2) n261 frequencies, the 3rd generation partnership project (3GPP) band n257, and the Federal Communications Commission’s (5G) high-band spectrum (25-30GHz).

GRB 210610B: The Internal and External Plateau as Evidence for the Delayed Outflow of Magnetar

After launching a jet, outflows of magnetar were used to account for the achromatic plateau of afterglow and the early X-ray flux plateau known as “internal plateau”. The lack of detecting magnetic dipole emission together with the energy injection feature in a single observation poses confusion until the long gamma-ray burst (GRB) 210610B is detected. GRB 210610B is presented with an optical bump following an early X-ray plateau during the afterglow phase. The plateau followed by a steep decline flux overlays in the steadily decaying X-ray flux with index α X,1 ∼ 2.06, indicating an internal origin and that can be fitted by the spin-down luminosity law with the initial plateau luminosity log10LX∼48.29ergs−1 and the characteristic spin-down timescale T ∼ 2818 s. A subsequent bump begins at ∼4000 s in the R band with a rising index α R,1 ∼ − 0.30 and peaks at ∼14125 s, after which a decay index α R,2 ∼ 0.87 and finally transiting to a steep decay with α R,3 ∼ 1.77 achieve the closure relation of the external shock for the normal decay phase as well as the magnetar spin-down energy injection phase, provided that the average value of the photon index Γ γ = 1.80 derived from the spectral energy distributions (SEDs) between the X-ray and optical afterglow. The closure relation also works for the late X-ray flux. Akin to the traditional picture of GRB, the outflow powers the early X-ray plateau by dissipating energy internally and collides with the leading decelerating blast burst as time goes on, which could interpret the exotic feature of GRB 210610B. We carry out a Markov Chain Monte Carlo simulation and obtain a set of best parameters: ϵ B ≃ 4.7 × 10−5, ϵ e ≃ 0.15, E K,iso ≃ 4.6 × 1053erg, Γ0 ≃ 832, A * ≃ 0.10, L inj,0 ≃ 3.55 × 1050erg s−1. The artificial light curve can fit the afterglow data well. After that, we estimated the average Lorentz factor and the X-ray radiation efficiency of the later ejecta are 35% and 0.13%, respectively.

Comprehensive view of a z ∼ 6.5 radio-loud quasi-stellar object: From the radio to the optical/NIR to the X-ray band

We present a multi-wavelength analysis, from the radio to the X-ray band, of the redshift z = 6.44 VIK J2318−31 radio-loud quasi-stellar object, one of the most distant currently known of this class. The work is based on newly obtained observations (uGMRT, ATCA, and Chandra) as well as dedicated archival observations that have not yet been published (GNIRS and X-shooter). Based on the observed X-ray and radio emission, its relativistic jets are likely young and misaligned from our line of sight. Moreover, we can confirm, with simultaneous observations, the presence of a turnover in the radio spectrum at νpeak ∼ 650 MHz that is unlikely to be associated with self-synchrotron absorption. From the near-infrared spectrum we derived the mass of the central black hole, $ M_{\mathrm{BH}}=8.1^{+6.8}_{-5.6} \times 10^8\,{M_{\odot}} $, and the Eddington ratio, $ \lambda_{\mathrm{EDD}} = 0.8^{+0.8}_{-0.6} $, using broad emission lines as well as an accretion disc model fit to the continuum emission. Given the high accretion rate, the presence of a ∼8 × 108 M⊙ black hole at z = 6.44 can be explained by a seed black hole (∼104 M⊙) that formed at z ∼ 25, assuming a radiative efficiency ηd ∼ 0.1. However, by assuming ηd ∼ 0.3, as expected for jetted systems, the mass observed would challenge current theoretical models of black hole formation.

Passive Radiative Cooling Materials and Their Applications

Abstract Passive radiative cooling naturally lowers the temperature of a cooler by reflecting sunlight and emitting heat into the frigid expanse of universe. While certain natural and synthetic substances may exhibit distinct radiative properties, their radiative efficiency remains minimal. As a result of the notable advancements in micro-nano technology, scientists have created several novel substances that exhibit minimal absorption within the intense solar spectrum (0.3-2.5 μm) but possess elevated emissivity in alternative wavelengths, ideally falling in the atmospheric window spectrum (8-13 μm). The basics of radiative cooling mechanisms are presented in this review, along with an overview of the progress made in radiative materials and their various applications. In upcoming times, this technology of passive radiative cooling, which consumes no energy and produces no greenhouse gases, will become a prominent approach for cooling purposes.

Development and Analysis of a Highly Compact Microstrip Patch Antenna for WiFi 6E Applications

In this research article, a microstrip patch antenna optimized for WiFi 6E applications is presented and analyzed. The antenna, constructed with an FR4 substrate measuring 20 × 24 × 1.53 mm³, adopts a rectangular shape and is designed using CST MWS® software. An equivalent circuit model is formulated and simulated with ADS software to ensure accurate representation. Operating at 6 GHz, simulated results from CST MWS® software indicate a bandwidth of 343 MHz (5.861 GHz to 6.204 GHz), while ADS software suggests 339 MHz (5.848 GHz to 6.187 GHz). In contrast, measured results exhibit a bandwidth of 196 MHz (5.827 GHz to 6.023 GHz). Despite slight discrepancies, satisfactory alignment is observed between computational and experimental outcomes, supported by the equivalent circuit model. Radiation patterns, gain, and efficiency are measured in an anechoic chamber and compared with simulations. E-plane shows directionality, while H-plane demonstrates omnidirectionality, aligning well with simulated patterns. The simulated gain is 5.77 dBi, measured gain is 5.61 dBi, resulting in a simulated efficiency of 93% and a measured efficiency of 88%. The antenna is deemed suitable for cost-effective WiFi 6E applications.

RESEARCH TREND ON IMPROVEMENT OF DIELECTRIC RESONATOR ANTENNA: A BIBLIOMETRIC ANALYSIS

Dielectric Resonator Antennas (DRAs) have components in modern wireless communication systems due to their compact size, high radiation efficiency, and frequency versatility. With escalating demands for higher data rates and spectrum efficiency, the enhancement of DRAs has garnered significant attention in antenna research. Despite the promising characteristics of DRAs, there exists a gap in providing a consolidated overview of the state-of-the-art advancements and emerging themes in DRA research. This study aims to bridge this gap by conducting a meticulous bibliometric analysis to delineate the research trends, highlight gaps, and guide future investigations. Our methodology involves a systematic search and analysis of scholarly publications related to the improvement of DRAs. We use bibliometric tools, citation analysis, and co-authorship networks to explore publication trends, influential authors, and collaborative networks within the DRA research community. By identifying emerging themes, key contributors, and collaborative networks, this study is poised to inform researchers, practitioners, and policymakers about the prevailing trends in the field. The insights gained are expected to guide future research directions, foster interdisciplinary collaboration, and contribute to the continued evolution of DRAs. In conclusion, this bibliometric analysis aims to provide a roadmap for navigating the intricate research landscape on the improvement of DRAs. The anticipated outcomes hold the potential to drive innovation, inspire collaborative initiatives, and contribute to the ongoing advancement of DRAs in the rapidly evolving realm of wireless communication systems.

A Thermal–EM Concentrator for Enhancing EM Signals and Focusing Heat Fluxes Simultaneously

AbstractThe simultaneous concentration of electromagnetic (EM) waves and heat fluxes in the same target region within an on‐chip system has substantial academic research importance and practical application value. However, the existing research is primarily aimed at the design and experimentation of concentrators for individual EM waves or temperature fields. In this study, a thermal‐EM concentrator capable of simultaneously concentrating EM waves and heat fluxes is designed using transformation optics and thermodynamics and fabricated using engineered thermal‐EM metamaterials. Both the numerically simulated and experimentally measured results demonstrate the concentrating capability of the proposed thermal‐EM concentrator, which can concentrate broadband transverse magnetic (TM)‐polarized EM waves ranging from 8 to 12 GHz and heat flux to the same target region within an on‐chip operating environment. The proposed thermal‐EM concentrator can be utilized for the efficient cooling of the specified component and for simultaneously enhancing the radiation and reception efficiency of the EM antenna within an on‐chip system.

Design of Miniaturized and Wideband Four-Port MIMO Antenna Pair for WiFi.

A miniaturized and wideband four-port multiple-input multiple-output (MIMO) antenna pair for Wi-Fi mobile terminals application is proposed. The proposed antenna pair consists of four multi-branch antenna elements arranged orthogonally, with an overall size of 40 × 40 × 3.5 mm3 and each antenna element size of 15.2 × 3.5 mm × 0.8 mm3. The performance of the proposed antenna shows the advantages of a wide frequency band, low mutual coupling, high efficiency, and a compact structure. The wideband characteristics of the antenna elements are achieved through multi-mode resonance. The suppression of coupling is accomplished by strategically positioning the four compact antenna elements to ensure their maximum radiation directions are orthogonal, thus eliminating the need for an additional decoupling structure. In this paper, the proposed antenna is optimized in terms of the parameters then simulated and measured. The simulated results illustrate that an impedance bandwidth of the antenna is about 15% (5.06~5.88 GHz) with S11 < -10 dB, excellent port isolation exceeds 20 dB between all ports, a high radiation efficiency ranges from 51.2% to 89.9%, the maximum gain is 4.5 dBi, and the ECCs are less than 0.04. The measured results show that the -10 dB impedance bandwidth of the antenna is about 13% (5.13~5.80 GHz), the isolation between the antenna elements is better than 21 dB, the radiation efficiency ranges from 51.8% to 92.3%, the maximum gain is 5.3 dBi, and the ECCs are less than 0.05. The proposed four-port MIMO antenna works on the 5G LTE band 46 and Wi-Fi 6E operating bands. As a mobile terminal antenna, the proposed design scheme demonstrates excellent performance and applicability, fulfilling the requirements for 5G mobile terminal applications.

Superhydrophobic stereocomplex-type polylactide/ultra-fine glass fibers aerogel for passive daytime radiative cooling

Passive daytime radiative cooling (PDRC) technology offers a green and sustainable strategy for cooling, eliminating the need for external energy sources through its exceptional efficiency in heat radiation and sunlight reflection. Despite its benefits, the widespread usage of non-biodegradable PDRC materials has unfortunately caused environmental pollution and resource wastage. Furthermore, the effectiveness of outdoor PDRC materials can be significantly diminished by rainfall. In this work, a superhydrophobic composite aerogel composed of stereocomplex-type polylactide and ultra-fine glass fiber has been successfully developed through simple physical blending and freeze-drying, which exhibits low thermal conductivity (36.26 mW m−1 K−1) and superhydrophobicity (water contact angle up to 150°). Additionally, its high solar reflectance (91.68 %) and strong infrared emissivity (93.95 %) enable it to effectively lower surface temperatures during daytime, resulting in a cooling effect of approximately 3.8 °C below the ambient temperature during the midday heat of summer, with a cooling power of 68 W/m2. This aerogel offers an environmentally friendly and sustainable approach for the utilization of radiative refrigeration materials, paving the way for environmental protection and sustainable development.

Simulation and Analysis of a Near-Perfect Solar Absorber Based on SiO2-Ti Cascade Optical Cavity

The main development direction for current solar technology is to improve absorption efficiency and stability. To bridge this gap, we design in this paper a structure consisting of two multilayer disc stacks of different radii, one topped by a TiO2 disc and the other by a cascade disc stack composed of SiO2-Ti, for use in thermal emitters and solar absorbers. The innovation of our work is the exploitation of multiple Fabry–Perot resonances in SiO2-Ti cascade optical cavities to develop absorber bandwidths while investigating it in the field of thermal emission and many aspects affecting the efficiency of the absorber. The finite difference time domain method (FDTD) results show absorption averages as high as 96.68% with an absorption bandwidth of 2445 nm (A &gt; 90%) at 280 nm–3000 nm solar incidence and even higher weighted averages as high as 98.48% at 1.5 solar air mass (AM) illumination. In order to investigate the physical mechanisms of our designed absorber in a high absorption state, we analyzed the electric field distributions of its four absorption peaks and concluded that its high absorption is mainly caused by the coupling of multiple Fabry–Perot resonance modes in the cascaded optical cavity. While considering this high efficiency, we also investigated the effect of complex environments such as extreme high temperatures and changes in the angle of incidence of the absorber, and the results show that the thermal radiation efficiency of the emitter is 96.79% at an operating temperature of 1700 K, which is higher than its thermal radiation efficiency of 96.38% at an operating temperature of 1500 K, which is a perfect result. On the other hand, we conclude that the designed structure is independent of polarization, while the absorber still has 88.22% absorption at incidence angles of up to 60°, both in transverse electric (TE) and transverse magnetic (TM) modes. The results of this study can help improve the performance of future solar absorbers and expand their application areas.

Design and Analysis of a Dual-Band Microstrip Patch Antenna for Sub-6 GHz Applications

This paper explores the design, simulation, and analysis of a dual-band Microstrip patch antenna designed to operate efficiently at frequency ranges of 3.32 GHz - 3.62 GHz and 4.72 GHz - 6.83 GHz, utilizing Ansys High-Frequency Structure Simulator (HFSS) software. The primary objective is to enhance performance metrics such as bandwidth, gain, and radiation efficiency to meet the requirements of applications necessitating concurrent operation at both frequency bands. The study involves a comprehensive design, iterative simulation, and detailed analysis using Ansys HFSS, with customized design considerations aimed at optimizing performance for modern wireless communication systems. The research was conducted in a simulated environment over a period that included iterative design processes, multiple simulation runs, and thorough analysis phases. Methodologically, the study focused on iterative design refinement to improve key performance parameters such as reflection coefficient, gain, radiation efficiency, Voltage Standing Wave Ratio (VSWR), and relative permittivity at the specified frequency bands. Results indicate that at 3.32 GHz - 3.62 GHz, the antenna achieves a reflection coefficient of -5 dB, a gain of 2.77 dB, a radiation efficiency of 0.7429, and a VSWR of 1.9299. At the higher frequency range of 4.72 GHz - 6.83 GHz, the antenna exhibits a reflection coefficient of -20.5213 dB, a gain of 3.34 dB, a radiation efficiency of 0.7, and a VSWR of 1.2203. These findings underscore the antenna's capability to deliver improved performance metrics across both frequency bands. In conclusion, the dual-band Microstrip patch antenna designed and analyzed through Ansys HFSS demonstrates significant potential for use in contemporary wireless communication systems, offering enhanced bandwidth, gain, and radiation efficiency suitable for multi-frequency applications.

Isolation enhancement of the F-shaped four-port MIMO antenna for WiMAX, Wi-Fi, WLAN and ISM band applications using dielectric material

In this article, an F-shaped four-port multiple-input multiple-output (MIMO) antenna is designed and analyzed. In the designed antenna for achieving high isolation, we introduced a novel isolation technique that appears like plus-shaped wall placed in between the antenna elements. The antenna is designed on a low-cost FR-4 epoxy substrate with total dimensions of 0.61 λ 0 × 0.61 λ 0 × 0.03 λ 0 (31 mm × 31 mm × 1.58 mm) where λ 0 is the free space wavelength at 5.8 GHz and experimentally verified. This MIMO antenna design covers operating the range of frequencies 5.47–6.20 GHz ( | S 11 | < − 10 dB) which provides a bandwidth of 730 MHz. In terms of performance, the proposed antenna achieves high isolation of < − 45.52 dB with an improved reflection coefficient of − 30.44 dB, a peak gain of 3.77 dBi and a radiation efficiency more than 82% across the entire operating band. Moreover, the achieved MIMO diversity parameters of the proposed antenna are envelope correlation coefficient < 0.005, diversity gain < 9.99 dB, mean effective gain < − 3 dB and total active reflection coefficient < − 10 dB in the operating band of frequency. The simulated and measured results show a good agreement between them. Finally, after analyzing the performance of the proposed MIMO configuration, we can say that this antenna is suitable for C-band, WiMAX, Wireless-Fidelity (Wi-Fi), Wireless Local-Area Network (WLAN), Bluetooth and Industrial, Scientific, & Medical (ISM) bands applications.

A compact ultra-wide band fractal antenna for breast cancer detection applications

A compact ultra-wide band antenna for breast cancer detection in bio-medical applications is presented in this study. The proposed antenna is printed on 1.6 mm thick FR4 substrate with a dielectric constant of 4.6 and tangential loss of 0.02. The uniform ground plane on the substrate (PCB) has been altered by shortening its length and making minimal changes to its side edges in order to improve overall bandwidth. The suggested antenna is functioning from 3 to 10.2 GHz which covers the ultra-wide band recommended by Federal Communication Commission (FCC) over the 10 dB impedance bandwidth. Additionally, the antenna has a significant overall gain of 3.2 dBi and an overall radiation efficiency of between 89 % and 92 %. Furthermore, the antenna maintains a uniform radiation pattern across its operating band. Parametric research has been conducted on the different parameters to tune the antenna into the required operating band, and placement analysis of the antenna is then investigated by assessing specific absorption rate (SAR).

Metasurface frequency reconfigurable antenna optimizes using neural network algorithm for wireless applications

Abstract As the demand increases in the field of wireless communication system, the interest of researchers increases to develop and analyzes the antenna for these applications. This article present metasurface (MS) frequency reconfigurable antenna (FRA) which is optimized using neural network (NN) approach. The designed structure is a multilayer consists of three-layer patch antenna placed under the MS structure. The resonating patch is a rectangular shaped and substrate is a circular shaped show as to reduce the geometry of the antenna. The proposed structure is fabricated on FR-4 substrate of thickness 1.6 mm. The MS structure consists of split ring rectangular (SRR) strips made up of copper. The antenna reconfigured the operating frequency from 4.85 to 7 GHz having overall bandwidth of 2.15 GHz with wide range of tuning. The central frequency of rectangular patch antenna is 6.15 GHz. The MS is analyzed by using effective parameters i.e., effective permittivity (ε r) &amp; effective permeability (μ r) and it is observed that the MS is behaving as a metamaterial in the desired range of frequency. The reconfigured operating frequency (ROF) is found at the anticlockwise rotation angles of 0°, 30°, 600 and 90°. The realized gain and radiation efficiency are calculated at each ROF. The validation of proposed MS based FRA is carried out first by simulating using Ansys HFSS and then measured inside the anechoic chamber. The proposed antenna is optimizes using NN model which shows minimum error during analysis and synthesis process.