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Kumar Vaibhav Srivastava

Bio: Kumar Vaibhav Srivastava is an academic researcher from Indian Institute of Technology Kanpur. The author has contributed to research in topics: Antenna (radio) & Radiation pattern. The author has an hindex of 33, co-authored 243 publications receiving 3904 citations. Previous affiliations of Kumar Vaibhav Srivastava include Indian Institutes of Technology & Indian Institute of Technology Delhi.


Papers
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Journal ArticleDOI
TL;DR: In this article, a low-profile microstrip-fed compact triple band-notched ultrawideband (UWB) antenna is proposed, where two elliptic single complementary split-ring resonators (ESCSRRs) of different dimensions from the radiating patch of the antenna are etched out.
Abstract: In this letter, a novel low-profile microstrip-fed compact triple band-notched ultrawideband (UWB) antenna is proposed. Notch bands around the 3.3-3.8-GHz WiMAX and 5.15-5.85-GHz WLAN frequencies are obtained by etching out two elliptic single complementary split-ring resonators (ESCSRRs) of different dimensions from the radiating patch of the antenna. Furthermore, by placing two rectangular split-ring resonators near the feedline-patch junction of the antenna, rejection for the 7.9-8.4-GHz X-band frequencies is achieved. Design guidelines for implementing the notch-bands at the desired frequency regions are provided. The match between the simulated and experimental results suggests that the proposed antenna can be a good candidate for application in UWB communication systems.

234 citations

Journal ArticleDOI
TL;DR: In this paper, a triple-band polarization-independent metamaterial absorber using square-shaped closed ring resonators over wide angle of incidence was proposed for airborne and surveillance radar signal absorption applications.
Abstract: In this paper, we propose a triple band polarization-independent metamaterial absorber using square-shaped closed ring resonators over wide angle of incidence. The unit cell consisting of various square loops is designed by using the parametric analysis so that it exhibits a triple band absorption response with two bands lying in C-band and one in X-band for airborne and surveillance radar signal absorption applications. Furthermore, in X-band, the absorber exhibits a broadband response with full width at half maxima bandwidth of 940 MHz (9.43%). The structure exhibits bandwidth enhanced properties for any angle of polarization under normal incidence. It also shows high absorption for wide angle of incidence up to 60°. The proposed structure is fabricated and experimental results show proper matching with the simulated responses.

221 citations

Journal ArticleDOI
TL;DR: In this paper, a triple band polarization-independent metamaterial absorber using electric field-driven LC resonators is proposed over wide angle of incidence, which exhibits triple band absorption property for any angle of polarization under normal incidence.
Abstract: In this paper, a triple band polarization-independent metamaterial absorber using electric field-driven LC resonators is proposed over wide angle of incidence. The unit cell is designed by parametric optimization in such a way that triple band absorption occurs in C-band. The proposed structure exhibits triple band absorption property for any angle of polarization under normal incidence. It also shows high absorption for wide angle of incidence upto 60° for both TE and TM polarizations. The proposed structure is also fabricated and experimental results provide good agreement with the simulated responses. The constitutive electromagnetic parameters viz. effective permittivity and effective permeability are extracted from the simulated response, which support the absorption phenomena at all these three frequencies. The reflection from the structure is numerically computed and verified with simulated response, and it shows good agreement between them.

175 citations

Journal ArticleDOI
TL;DR: In this article, a broadband polarisation-independent circuit analogue absorber comprising multi-layer resistive frequency selective surfaces (FSS) is presented, which shows good matching with the full-wave analysis.
Abstract: A broadband polarisation-independent circuit analogue absorber comprising multi-layer resistive frequency selective surfaces (FSS) has been presented in this study. The proposed structure consists of a periodic arrangement of square loops loaded with lumped resistors and these square loops are printed on dielectric substrates separated by an air spacer. The simulated result shows the reflectivity below -10 dB in the frequency range from 4.96 to 18.22 GHz (fractional bandwidth of 114.40%) under normal incidence, covering C, X, and Ku bands. An equivalent circuit analysis has been introduced to characterise the proposed absorber, which shows good matching with the full-wave analysis. The effects of the individual FSS layers and the air spacer have been studied and several parametric variations have been carried out to examine the sensitivity of the design parameters on the absorption bandwidth. Finally, the designed absorber has been fabricated and measured in anechoic chamber, which shows good agreement between the experimental results and the simulated responses, under different angles of incidence as well as for various polarisation angles.

157 citations

Journal ArticleDOI
TL;DR: In this article, a bow-tie-shaped slot antenna is proposed to induce strong loading effect in the cavity and generate two closely spaced hybrid modes that help to get a broadband response.
Abstract: A novel design technique for broadband substrate integrated waveguide cavity-backed slot antenna is demonstrated in this letter. Instead of using a conventional narrow rectangular slot, a bow-tie-shaped slot is implemented to get broader bandwidth performance. The modification of the slot shape helps to induce strong loading effect in the cavity and generates two closely spaced hybrid modes that help to get a broadband response. The slot antenna incorporates thin cavity backing (height <;0.03λ 0 ) in a single substrate and thus retains low-profile planar configuration while showing unidirectional radiation characteristics with moderate gain. A fabricated prototype is also presented that shows a bandwidth of 1.03 GHz (9.4%), a gain of 3.7 dBi over the bandwidth, 15 dB front-to-back ratio, and cross-polarization level below -18 dB.

152 citations


Cited by
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Journal ArticleDOI
TL;DR: The method of utilizing an external voltage to break the intrinsic dielectric feature by modifying a traditional electronic absorption device is demonstrated for the first time and has great significance in solving the low-frequency electromagnetic interference issue.
Abstract: Nowadays, low-frequency electromagnetic interference (<2.0 GHz) remains a key core issue that plagues the effective attenuation performance of conventional absorption devices prepared via the component-morphology method (Strategy I). According to theoretical calculations, one fundamental solution is to develop a material that possesses a high e' but lower e″. Thus, it is attempted to control the dielectric values via applying an external electrical field, which inducts changes in the macrostructure toward a performance improvement (Strategy II). A sandwich-structured flexible electronic absorption device is designed using a carbon film electrode to conduct an external current. Simultaneously, an absorption layer that is highly responsive to an external voltage is selected via Strategy I. Relying on the synergistic effects from Strategies I and II, this device demonstrates an absorption value of more than 85% at 1.5-2.0 GHz with an applied voltage of 16 V while reducing the thickness to ≈5 mm. In addition, the device also shows a good absorption property at 25-150 °C. The method of utilizing an external voltage to break the intrinsic dielectric feature by modifying a traditional electronic absorption device is demonstrated for the first time and has great significance in solving the low-frequency electromagnetic interference issue.

657 citations

Proceedings Article
01 Jan 2004
TL;DR: In this paper, a SiGe amplifier with on-chip matching network spanning 3-10 GHz was presented, achieving 21dB peak gain, 2.5dB noise figure, and -1dBm input IP3 at 5 GHz, with a 10-mA bias current.
Abstract: Reactive matching is extended to wide bandwidths using the impedance property of LC-ladder filters. In this paper, we present a systematic method to design wideband low-noise amplifiers. An SiGe amplifier with on-chip matching network spanning 3-10 GHz delivers 21-dB peak gain, 2.5-dB noise figure, and -1-dBm input IP3 at 5 GHz, with a 10-mA bias current.

342 citations

Journal ArticleDOI
TL;DR: In this paper, the authors presented a review of the Advanced Optical Materials Hall of Fame article series, which recognizes the excellent contributions of leading researchers to the field of optical materials science. But they did not mention the work of the authors of this article.
Abstract: This work was supported by National Basic Research Program of China (Project No. 2013CB933301) and National Natural Science Foundation of China (Project No. 51272038). L.V.B. was supported by China Postdoctoral Science Foundation. A.O.G. was supported by the Volkswagen Foundation (Germany) and via the Chang Jiang (Yangtze River) Chair Professorship (China). G.P.W. acknowledges support from the Center for Nanoscale Materials, a U.S. Department of Energy Office of Science User Facility, and support by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357. In addition, the authors acknowledge financial support obtained from the Virtual Institute for Theoretical Photonics and Energy. This review is part of the Advanced Optical Materials Hall of Fame article series, which recognizes the excellent contributions of leading researchers to the field of optical materials science.

321 citations

Journal ArticleDOI
TL;DR: A novel core-shell composite for microwave absorption application in which the α-Fe2O3 and the porous Co Fe2O4 nanospheres served as the core and shell, respectively, which provided a promising approach for preparing an absorbent with good absorption intensity and a broad frequency that was lightweight.
Abstract: In this paper, we designed a novel core-shell composite for microwave absorption application in which the α-Fe2O3 and the porous CoFe2O4 nanospheres served as the core and shell, respectively. Interestingly, during the solvothermal process, the solvent ratio (V) of PEG-200 to distilled water played a key role in the morphology of α-Fe2O3 for which irregular flake, coin-like, and thinner coin-like forms of α-Fe2O3 can be produced with the ratios of 1:7, 1:3, and 1:1, respectively. The porous 70 nm diameter CoFe2O4 nanospheres were generated as the shell of α-Fe2O3. It should be noted that the CoFe2O4 coating layer did not damage the original shape of α-Fe2O3. As compared with the uncoated α-Fe2O3, the Fe2O3@CoFe2O4 composites exhibited improved microwave absorption performance over the tested frequency range (2-18 GHz). In particular, the optimal reflection loss value of the flake-like composite can reach -60 dB at 16.5 GHz with a thin coating thickness of 2 mm. Furthermore, the frequency bandwidth corresponding to the RLmin value below -10 dB was up to 5 GHz (13-18 GHz). The enhanced microwave absorption properties of these composites may originate from the strong electron polarization effect (i.e., the electron polarization between Fe and Co) and the electromagnetic wave scattering on this special porous core-shell structure. In addition, the synergy effect between α-Fe2O3 and CoFe2O4 also favored balancing the electromagnetic parameters. Our results provided a promising approach for preparing an absorbent with good absorption intensity and a broad frequency that was lightweight.

307 citations