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Ashutosh Singh

Bio: Ashutosh Singh is an academic researcher from B. R. Ambedkar Bihar University. The author has contributed to research in topics: Metamaterial absorber & Resonator. The author has an hindex of 3, co-authored 6 publications receiving 14 citations. Previous affiliations of Ashutosh Singh include Memorial University of Newfoundland.

Papers
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Journal ArticleDOI
12 Sep 2018
TL;DR: In this article, a new design of a metamaterial absorber (MMA) with two broad-bands is simulated, fabricated and experimentally investigated in a new framework.
Abstract: A new design of a metamaterial absorber (MMA) with two broad-bands is simulated, fabricated and experimentally investigated in this paper. The MMA structure unit cell consists of combination of eight rings with two pair of concentric split rings and two pair of concentric continuous rings placed diagonally opposite. The proposed MMA has x-y symmetrical copper unit cells with middle layer of FR-4 substrate and copper laminated ground plane. The simulated and measured absorption peaks as well as the absorptance of the proposed MMA exhibits insensitivity to change in polarization and incidence angle of electromagnetic waves. The metamaterial behavior of the studied MMA is confirmed by extracting effective permeability, μ eff(f), effective permittivity, e eff(f), and effective refractive index, η eff(f), from the measured S-parameters. The proposed MMA has resonance peaks at 7.6 GHz, 8.9 GHz, 12.3 GHz, and 12.8 GHz with measured absorptance of 94%, 99.9%, 96%, and 96% at respective frequency bands. The first absorption broad-band extends from 7.36 GHz to 9.36 GHz and the second broad-band extends from 11.9 GHz to 13 GHz. The high electromagnetic wave absorptance from 7.36 GHz–9.36 GHz and 11.9 GHz–13 GHz makes this MMA suitable for satellite, mobile and radar applications.

9 citations

Proceedings ArticleDOI
01 Jan 2016
TL;DR: In this article, the authors presented the design, simulation and parametric analysis of a concentric continuous and split rings resonator (CCRR, CSRR) structure for a dual broadband metamaterial (MM) absorber.
Abstract: This paper presents the design, simulation and parametric analysis of a concentric continuous and split rings resonator (CCRR, CSRR) structure for a dual broadband metamaterial (MM) absorber. The MM structure unit cell consists of concentric circular split rings of same width and different radii and concentric continuous rings of different width and different radii arranged in four different quadrants. The three layered proposed MM absorber design has upper layer comprising of concentric continuous and split rings structured sub-cells separated by bottom laminated copper layer of FR-4 substrate. The proposed MM absorber is insensitive to any polarization state of incident EM waves due to highly symmetrical circular and split ring structures. The scattering parameter and absorption coefficient are obtained for the present MM absorber. The magnetic and electric fields are monitored to realize the behavior of MM structure. The dual broadband MM absorber has absorbance of 99% from 7.785 GHz – 8.475 GHz and absorbance of 98% from 11.835 GHz – 12.81 GHz. The absorption peaks for this MM absorber are obtained as 99.5%, 99.6%, 98.4% and 98.8% at 7.785 GHz, 8.475 GHz, 11.835 GHz and 12.81 GHz frequencies respectively for the normal incidence of EM waves. The high absorbance makes this MM absorber suitable for various microwave applications including airborne and radar signal absorption.

4 citations

01 May 2016
TL;DR: In this paper, the authors presented the design, simulation and parametric analysis of a concentric continuous ring resonator structure for a multiband metamaterial (MM) absorber.
Abstract: This paper presents the design, simulation and parametric analysis of a concentric continuous ring resonator structure for a multiband metamaterial (MM) absorber. The unit cell of MM structure consists of concentric annular rings of different radii as well as width arranged in four different quadrants. The three layered proposed MM absorber design has an upper layer comprising of continuous annular ring structured sub-cells separated by a bottom laminated copper layer of FR4 substrate. The highly symmetrical annular ring structures in nature make this absorber insensitive to any polarization state of incident EM waves. The scattering parameter and absorption coefficient are obtained for the present MM absorber. The electric and magnetic fields are monitored to realize the behavior of MM structure. The absorbance for this MM absorber are also obtained as 98%, 98%, 96% and 92% at 7.102 GHz, 9.104 GHz, 12.558 GHz and 13.097 GHz frequencies respectively for the normal incidence of EM waves. The high absorbance makes this MM absorber suitable for various microwave applications including airborne and radar signal absorption.

4 citations

Journal ArticleDOI
TL;DR: In this article, the authors present results from the simultaneous assessment of Tweeks (radio atmospherics) and radio signals (fixed frequency of the transmitter's signal) from multifarious VLF transmitters observed at Varanasi (Geog. Lat. 82.980 E, Geomag. lat. 120 58/ N, long.

3 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, the design characterization of metamaterial absorber (MMA) has been analyzed for a unit cell structure of shorted stubs circular rings metammaterial absorber.
Abstract: In this research work, the design characterization of metamaterial absorber (MMA) has been analysed for a unit cell structure of shorted stubs circular rings metamaterial absorber. The simulated results show that dual resonance peaks occur at 17 GHz and 18 GHz with absorbance peak response of 99.99% and 99.83%, almost unity absorbance. The corresponding full width at half maximum (FWHM) bandwidth at these resonant frequencies are 4.90% and 5.07% respectively. A parametric study has been done to analysed the effect of variation of circular ring radius, shorted stubs length and rectangular bar length upon the resonance frequency. The analysis shows that we can achieve a lower resonant frequency with almost unity absorbance. Moreover, the resonant frequency drifts to lower value without affecting absorbance. The effect at oblique angle of incidence and polarization sensitivity is also considered for both TE and TM modes. So, this unit cell structure acts as a controllable and tunable MMA structure. The dual resonances MMA structure are becoming a prime technology for many present and future wireless communication systems such as radar cross section (RCS) reduction for stealth technology, satellite navigation systems, radar frequency identification and wireless handheld devices.

33 citations

Journal ArticleDOI
22 Feb 2019
TL;DR: In this paper, a compact quad-band polarization-independent metamaterial absorber for different microwave frequency bands has been presented, which exhibits the absorption peaks greater than 90% at 3.1 GHz, 5.5 GHz, 7.6 GHz and 10.98 GHz under the normal incidence.
Abstract: In the paper, a compact quad-band polarization-independent metamaterial absorber has been presented for different microwave frequency bands. The proposed absorber unit cell comprises of two square and two concentric circular rings and it exhibits the absorption peaks greater than 90% at 3.1 GHz, 5.5 GHz, 7.6 GHz and 10.98 GHz respectively under the normal incidence. The full width at half maximum (FWHM) bandwidth is 150 MHz (3.03–3.18 GHz), 180 MHz (5.38–5.56 GHz), 330 MHz (7.44–7.77 GHz), and 560 MHz (10.70–11.26 GHz) at the four frequency bands. The proposed absorber is polarization and incidence angle insensitive due its symmetrical. The proposed structure also shows more than 90% absorptivity up to 60° incidence angle. The absorber unit cell is compact in configuration with size of 0.12 λ o × 0.12 λ o and ultrathin thickness of 0.016 λ o, where λ o is the wavelength at lowest frequency absorption peak. To recognize the absorption phenomenon of the absorber, input impedance, E-field and surface current distribution characteristics have been demonstrated. The structure has been fabricated and it shows good agreement between simulated and measured results.

28 citations

Journal ArticleDOI
TL;DR: In this article, a closed ring resonator-based absorber with eleven consecutive absorption peaks is proposed over X and K bands with an average absorption rate of 96.29% for radar cross section reduction application.
Abstract: In this article, a closed ring resonator-based absorber with eleven consecutive absorption peaks is proposed over X and K bands with an average absorption rate of 96.29%. The proposed design consists of circular ring resonators embedded in the circularly slotted square patch printed on the top of the grounded FR-4 substrate. The surface current distributions well illustrates the reason behind the electromagnetic (EM) wave absorption. The design is polarization insensitive for normal incidence and wide angular stable up to 45° for TE (60° for TM) polarization. The structure is fabricated on a single-layered FR-4 dielectric substrate with a periodicity of ${{\boldsymbol{\lambda }}_{\boldsymbol{o}}}$ /2.32 and thickness of ${{\boldsymbol{\lambda }}_{\boldsymbol{o}}}$ /16.74, where ${{\boldsymbol{\lambda }}_{\boldsymbol{o}}}$ is the free-space wavelength at the lowest resonant frequency. A transmission line-based equivalent circuit model has been illustrated and good agreement is observed with full-wave simulations. This article's novelty lies in the absorption mechanism of eleven consecutive absorption peaks, demonstrating the controllability of the absorptivity peaks and resonant frequency. To the best of the authors’ knowledge, the proposed absorber demonstrates the highest number of near-unity successive absorption bands with better angular stability. The proposed structure was checked for radar cross section reduction application with an X -band antenna and results show 19.7-dBsm reduction at normal incidence.

25 citations

Journal ArticleDOI
TL;DR: In this article, a multiband metamaterial (MM) absorber based on a novel spiral resonator with continuous, dual, and opposite P-shape was proposed for TEM mode.
Abstract: This paper presents a multiband metamaterial (MM) absorber based on a novel spiral resonator with continuous, dual, and opposite P-shape. The full wave analysis shows 80.06% to 99.95% absorption at frequencies range for Ku and K bands for several substrate materials of 100 mm2 area. The results indicate that the absorption rate remains similar for different polarizing angles in TEM mode with different substrates. With FR4 (Flame Retardant 4) substrate and 64 mm2 ground plane, the design acts as single negative (SNG) MM absorber in K band resonance frequencies (19.75–21.37 GHz) and acts as double negative (DNG) absorber in Ku band resonance frequencies (15.28–17.07 GHz). However, for Rogers 3035 substrate and 36 mm2 ground plane, it acts as an SNG absorber for Ku band resonance frequency 14.64 GHz with 83.25% absorption and as a DNG absorber for K band frequencies (18.24–16.15 GHz) with 83.69% to 94.43% absorption. With Rogers 4300 substrate and 36 mm2 ground plane, it acts as an SNG absorber for Ku band at 15.04 GHz with 89.77% absorption and as DNG absorber for K band frequencies (22.17–26.88 GHz) with 92.87% to 93.72% absorption. The design was fabricated with all three substrates and showed quite similar results as simulation. In comparison with other broadband absorbers, this proposed MM absorber illustrated broad incidence angles in TEM mode.

22 citations

Journal ArticleDOI
TL;DR: In this paper , a multiband Yagi-Uda shaped metamaterial absorber (YUMA) operating in X-and Ku-band of the microwave regime with the added functionalities of miniaturization, polarization controllability and wide incidence angle stability was reported.
Abstract: This paper reports a multiband Yagi-Uda shaped metamaterial absorber (YUMA) operating in X- and Ku-band of the microwave regime with the added functionalities of miniaturization, polarization controllability and wide incidence angle stability. The proposed YUMA shows three distinctive near-unity absorption peaks corresponding to 10.64 GHz, 12.08 GHz, and 14.09 GHz frequencies. The YUMA was analyzed under different oblique incidence angles for transverse electric (TE)-mode and different rotation angles of the top metasurface. The results showed that the proposed YUMA possesses multifunctional characteristics such as polarization controllability, and wide incidence angle stability. The comparison of simulated and measured results further demonstrates that the proposed absorber can be a potential candidate in polarization detection systems and transmissive polarizers. The proposed YUMA operating in the X- and Ku-band can have potential uses in several other applications, such as air traffic control, weather monitoring, military radar, and satellite communication.

20 citations