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Rajesh Natarajan

Bio: Rajesh Natarajan is an academic researcher from VIT University. The author has contributed to research in topic(s): Radiation pattern & Vivaldi antenna. The author has an hindex of 10, co-authored 18 publication(s) receiving 383 citation(s). Previous affiliations of Rajesh Natarajan include Valliammai Engineering College & Anna University.
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Journal ArticleDOI
Abstract: In this letter, a compact frequency selective surface (FSS) composed of a modified swastika unit cell having the smallest dimension of 7 × 7 mm2 is proposed. The design is aimed at the rejection of 5-GHz WLAN band. The unit-cell geometry resembles the shape of crossed dipoles to achieve compactness. The proposed FSS provides 400 MHz bandwidth with 20 dB insertion loss. The proposed design holds a stable response for TE and TM modes of polarization as well as oblique incidence angles, thus ensuring polarization and angular independent operation. The simulated results are validated with measured results obtained from the fabricated FSS.

76 citations

Journal ArticleDOI
Abstract: A compact antipodal Vivaldi antenna (AVA) with the dimension of $42 \times 36 \times 1.6~\hbox{mm}{^3}$ is proposed in this letter. Structural modifications in the radiating fins have increased the electrical length thereby reducing the lower operating frequency from 5.2 GHz to 3.7 GHz. Proposed antenna maintains $-20~\hbox{dB}$ copolarization to cross-polarization ratio throughout the operating bandwidth. The prototype is fabricated and the measurement results are presented to validate the performance of the proposed AVA.

71 citations

Journal ArticleDOI
TL;DR: Two triband RFID antennas are proposed, one for the radio frequency identification (RFID) reader and the other for the RFID tag, each operating at 3.6, 5.8, and 8.2 GHz.
Abstract: In this letter, two triband RFID antennas are proposed, one for the radio frequency identification (RFID) reader and the other for the RFID tag. The antenna is the crucial part in designing any RFID system. The reader antenna operates at 3.6, 5.8, and 8.2 GHz. The tag antenna operating frequencies are 3.9, 5.9, and 8.2 GHz. The applications of these frequencies are RFID for logistics management, traffic toll collection, and tagometry (telemetry using RFID), respectively. Fractal structures are employed as radiating elements for this multiband antenna.

70 citations

Journal ArticleDOI
Abstract: This paper describes a novel FSS which functions as band stop fllter to shield the GSM 1800MHz downlink band. The FSS is designed to operate with the resonant frequency of 1820MHz which is the centre frequency for the GSM 1800MHz downlink band. The novelty is attributed to its unique geometry and the circular apertures endowed with it. The proposed geometry provides shielding efiectiveness of 20dB alongside with 133MHz bandwidth. The structure holds identical response for both TE and TM Modes of polarization. In addition, the geometry with its circular apertures, a hitherto unexplored feasibility serves the purpose of ventilation and heat dissipation. The simulated results are validated using experimental measurements.

30 citations

Journal ArticleDOI
Abstract: In this study, a modified antipodal Vivaldi antenna (AVA) with low cross-polarisation is proposed for ultra-wideband communications. The bandwidth offered by conventional single petal AVA is enhanced by adding another petal. This dual petal antenna occupies a small volume of 60 × 60 × 0.8 mm 3 and provides operating bandwidth from 2.4 GHz to frequencies >14 GHz. The proposed antenna configuration provides low cross-polarisation level which is 5 dB and an average group delay variation of 0.5 ns. The prototype antenna is fabricated and tested to validate the simulation results.

27 citations

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Journal ArticleDOI
Abstract: An efficient approach to achieve the shielding effectiveness (SE) by using a frequency-selective surface (FSS) is presented. This FSS, which consists of cross dipoles and rings printed on the opposite sides of a single-layer FR-4 substrate, exhibits a wide, 7.5-GHz stopband to provide simultaneous shielding in both X- and Ka-bands. Experimental results confirm SE of the prototype over an ultra-wide band with more than 20-dB measured attenuation. The design is compact and suitable to provide shielding against the radiation interference caused by license-free and other radio systems.

144 citations

Journal ArticleDOI
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.

97 citations

Journal ArticleDOI
Abstract: In this letter, we propose an anchor-shaped loop unit-cell structure for compact frequency selective surfaces (FSSs) with dual-bandstop behavior in two wireless local area network (WLAN) frequencies 2.4 and 5.0 GHz. The proposed FSS possesses 230- and 300-MHz bandwidths with insertion loss less than ${-}$ 20 dB around the two central operating frequencies 2.4 and 5.0 GHz, respectively. In addition, the FSS exhibits excellent miniaturization with 0.065 $\lambda \times 0.076 \lambda$ unit cells, where $\lambda$ represents the free-space wavelength. Furthermore, the unit-cell structure provides a stable performance for both TE- and TM- polarizations under incident angles 0 $^{\circ}$ –60 $^{\circ}$ . A prototype of the proposed FSS is fabricated and measured. Good agreement between the simulated and measured results is obtained.

93 citations

Journal ArticleDOI
Ravi Panwar1, Jung-Ryul Lee2Institutions (2)
Abstract: This article analyzes a review of recent developments in the field of frequency selective surface (FSS)-based advanced electromagnetic (EM) structures. FSSs have been the subject of intensive investigation for distinct EM applications for more than four decades. An FSS is a type of filter consisting of an array of periodic metallic patches or apertures on a dielectric substrate. The high-pass (inductive FSS) and low-pass (capacitive FSS) filtering operation of FSS results in the exhibition of total transmission and reflection near the resonance wavelength. This paper deals with an overview of different FSS geometries, namely, traditional, active, fractal, three-dimensional and multilayered FSSs. A number of recent practical EM applications of FSS structures like microwave absorbers, radomes, textiles and antennas are discussed. In addition, different types of optimization and fabrication techniques for FSS-based EM structures are incorporated. The FSS-based research directions described in this study may be of interest to the scientific community working in this particular field.

93 citations

Journal ArticleDOI
Abstract: In this paper, a novel and miniaturized band-stop frequency selective surface (FSS) is presented. This FSS provides effective shielding in X-band, with attenuation of at least 56 dB. The proposed FSS provides 3-dB fractional bandwidth of 48% which is necessary to cover X-band. Moreover, the proposed design is polarization independent as it provides a stable frequency response at normal and oblique angles of incidences for both perpendicular TE and parallel TM wave modes. The copolarized and cross-polarized scattering parameter $S_{21}$ is analyzed at the selected band-stop/notch frequencies. More importantly, the proposed FSS is suitable for conformal applications and hence finds wider employability. A prototype of the proposed FSS is fabricated and tested. The measured results are in good agreement with the simulated results.

68 citations

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Author's H-index: 10

No. of papers from the Author in previous years