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Author

V. Rajeshkumar

Bio: V. Rajeshkumar is an academic researcher from VIT University. The author has contributed to research in topics: Antenna (radio) & Monopole antenna. The author has an hindex of 8, co-authored 16 publications receiving 187 citations. Previous affiliations of V. Rajeshkumar include Sona College of Technology & National Institute of Technology, Tiruchirappalli.

Papers
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Journal ArticleDOI
TL;DR: In this paper, a triple-band antenna for the frequency bands 2.4, 3.5 and 5 GHz is proposed for the IEEE 802.11a/b/g and 802.16e standards.
Abstract: This paper presents a compact triple band antenna for the frequency bands 2.4, 3.5 and 5 GHz. These bands are assigned to the IEEE 802.11a/b/g and IEEE 802.16e standards. The resonant modes for WLAN, WiMAX bands are achieved by employing a rectangular slot and a metamaterial inspired split ring structure. The extraction procedure of negative permeability for the proposed split ring resonator is discussed in detail. Tunability between the WLAN and WiMAX standards is demonstrated by using a single PIN diode. The proposed antenna with a compact size of 27 mm × 25 mm is fabricated and tested. The triple band antenna yields a −10 dB impedance bandwidth of about 18.6%, 4.3% and 40.3% in 2.4, 3.5 and 5 GHz bands respectively. Stable radiation patterns with low cross polarization and high average antenna gain of 2.46 dBi are observed for the operating bands.

82 citations

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TL;DR: In this article, a compact asymmetric coplanar strip (ACS)-fed monopole antenna is presented, which consists of a tapered shaped radiating element and a meta-atom (complementary split ring resonator-CSRR), loaded in the ground plane.
Abstract: In this paper, a compact asymmetric coplanar strip (ACS)-fed monopole antenna is presented. The proposed antenna consists of a tapered shaped radiating element and a meta-atom (complementary split ring resonator-CSRR), loaded in the ground plane which helps in obtaining multiband characteristics with proper impedance matching performance. Antenna with dimensions of 25 × 12.2 × 1.6 mm3 has been designed, fabricated and tested. The experimental result that exhibits of −10 dB impedance bandwidth by the proposed antenna at the center frequency of 2.88 GHz (1100 MHz), 5.78 GHz (1940 MHz) and 7.64 GHz (660 MHz). It covers wireless applications namely wireless local area network (WLAN) 2.4/5.2/5.8 GHz, long-term evolution (LTE) LTE 2.5 GHz, public safety applications 4.9 GHz, worldwide interoperability for microwave access (WiMAX) 5.5 GHz, wireless access for vehicular environments (WAVE) 5.9 GHz and X-band downlink frequency band 7.5 GHz. The antenna has good radiation characteristics in both E-plane and H-plane for all the operating frequencies. The proposed antenna exhibits a better performance compared to the previously reported designs to the existing antenna designs which are discussed in the literature. Moreover, the antenna possesses compact size, the total size occupied by the design is 0.20λ0 × 0.1λ0.

23 citations

Journal ArticleDOI
TL;DR: In this paper, a multiband loaded trapezoidal ring fractal antenna (TRFA) is proposed for wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications.
Abstract: A novel multiband loaded trapezoidal ring fractal antenna (TRFA) is proposed for wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications The self-similarity property is applied to the trapezoidal structure and the fractal geometry is achieved by consecutive iterations The proposed antenna has a compact size of 30 × 30 × 16 mm3 The antenna is fabricated and tested The fourth iteration of the proposed TRFA covers the 24/52/58 GHz WLAN bands and 25/35/55 GHz WiMAX bands with uniform radiation characteristics and an average gain of 220 dBi © 2014 Wiley Periodicals, Inc Microwave Opt Technol Lett 56:2545–2548, 2014

21 citations

01 Jan 2013
TL;DR: In this paper, the design concept of metamaterial antennas in ISM band is presented and the funda-mental theory and recent progress of metAMaterial in sensors, lenses and absorbers are reviewed for various healthcare applications towards its practical implementation.
Abstract: Communication technologies and biomedical sensors can provide services for the patient's vital signs to be monitored outside the clinical environment. The need for implantable telecommunication devices for medical applications has been growing rapidly over the past ten years. Microwave antennas and sensors are key components of telemetry systems related to medi- cal applications. Metamaterials are artiflcial materials which have the electromagnetic properties that may not be found in nature. The unusual properties of a metamaterial have led to the development of metamaterial antennas, sensors and metamaterial lenses for miniature wireless systems which are more e-cient than their conventional counterparts. Metamaterials exhibit a very sensitive response to the strain, dielectric media, chemical and biological sensing appli- cations. A wide area of biomedical applications using metamaterials has been discussed in this review. The design concept of metamaterial antennas in ISM band is presented. Later, the funda- mental theory and recent progress of metamaterial in sensors, lenses and absorbers are reviewed for various healthcare applications towards its practical implementation.

19 citations

Journal ArticleDOI
TL;DR: In this paper, a compact split ring resonator-based polygon ring fractal multiband antenna is presented, and the operating frequencies of the proposed antenna are 1.8 GHz GSM, 2.4/5 GHz wireless local area network, 3.5 GHz worldwide interoperability for microwave access and 7 GHz ITU bands.
Abstract: In this article, a compact split ring resonator-based polygon ring fractal multiband antenna is presented. The operating frequencies of the proposed antenna are 1.8 GHz GSM, 2.4/5 GHz wireless local area network, 3.5 GHz worldwide interoperability for microwave access, and 7 GHz ITU bands. The self-similarity fractal property and split rings are utilized in the regular 12-sided polygon to get multiple frequency bands. Parametric studies are performed to study the effects of different parameters as well as to obtain the desired frequency bands with optimum performance. The proposed antenna with a compact size of 24 × 18 × 1.6 mm3 is fabricated and tested to validate against simulation results. Measured antenna characteristic shows close agreement with the simulation. Also, uniform radiation characteristic is observed in the entire frequency bands of interest. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1301–1305, 2015

16 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, a simple, highly sensitive, and compact footprint biosensor for cancer detection based on metamaterial containing structure utilizing theoretical model is presented, which includes array of split ring resonators on a dielectric substrate.
Abstract: In the present paper, we aim to report a simple, highly sensitive, and compact footprint biosensor for cancer detection based on metamaterial containing structure utilizing theoretical model. This model includes of array of split ring resonators on a dielectric substrate. The proposed structure is simulated using three-dimensional finite-element method. To achieve the appropriate operation, the effects of the physical properties including dielectric material, and different cells on the performance of the proposed sensor are considered. For this purpose, three types of dielectrics, including silicon dioxide (SiO2), titanium dioxide (TiO2), and polymethyl methacrylate (PMMA) substrates have been used to evaluate the biosensor. Calculated sensitivity values for SiO2, TiO2, and the PMMA are 658, 653, and 633, respectively, while the figure of merit for these three sub-layers are 258, 2431, and 225. According to the simulation results, when the refractive index of a sub-layer is closer to the refractive index of the samples, the sensor is more sensitive. Also, due to the nanometer size of SSRs, it is easy to detect nanometer-sized specimens. The biosensor has a very high resolution so that the capability of measurement and the detection of cancer cells are enhanced.

91 citations

Journal ArticleDOI
TL;DR: In this article, a novel four band frequency reconfigurable antenna for 1.6, 2.5, 5.8, and 9.8 GHz frequency bands is presented, which has a compact size of 0.18 λ 0 × 0.
Abstract: This research presents a novel four band frequency reconfigurable antenna for 1.6 (Global Navigation Satellite system (GNSS)), 2.5 (Lower Worldwide Interoperability for Microwave Access (WiMAX)), 5.8 (Wireless local area network (WLAN)) and 9.8 GHz (X-band) frequency bands. The antenna has a compact size of 0 . 18 λ 0 × 0.18 λ 0 × 0.0096 λ 0 at lower resonance of 1.8 GHz and is printed on FR4 material with height (h) = 1.6 mm, dielectric constant ( ( e r ) = 4.4 and loss tangent ( δ ) = 0.02. Multiband phenomenon in the antenna is achieved by etching trapezoidal slot in the radiating monopole and rectangular slots in the ground plane. Frequency reconfiguration in the proposed structure is achieved by placing PIN diode switch between rectangular slot placed in the ground plane. During OFF state, the antenna exhibit quad band with S11

83 citations

Journal ArticleDOI
TL;DR: This work reviews current advancements in the design and fabrication of multi-scale advanced structures with properties heretofore unseen in well-established materials and suggests some guidelines on the selection of fabrication parameters to construct meta-biomaterials for tissue engineering.

63 citations

Journal ArticleDOI
TL;DR: In this paper, a triple-notch ultra-wideband (UWB) monopole antenna with fractal Koch and T-shaped stub is presented, which is based on a circular monopole with a backplane feed line modified for 2-11 GHz in an omnidirectional pattern.
Abstract: In this study, a triple-notch ultra-wideband (UWB) monopole antenna with fractal Koch and T-shaped stub is presented. The prototype antenna is based on a circular monopole antenna with a back-plane feed line modified for 2–11 GHz in an omnidirectional pattern. By implementing a combination of fractal Koch and T-shaped stub on the antenna, a triple-notch band occurred at 2, 3.5, and 5.8 GHz for rejecting personal communication services (PCS), worldwide interoperability for microwave access (WiMAX), and wireless local area network (WLAN). In addition to the UWB application frequency range of 3.1–10.6 GHz, the final antenna covers a frequency range of 1.78–1.91 GHz for GSM 1800, 2.28–3.120 GHz for Wi-Fi, and 2.4 GHz for Bluetooth applications with a voltage standing wave ratio (VSWR) < 2. Simulated results of HFSS and CST are compared with experimental results. The dimensions of the antenna are 50 mm × 50 mm × 1.6 mm. The current distribution and efficiency at notch frequency are noted for the whole frequency band, and the maximum antenna gain is between −3.5 and 6.5 dBi. In this study, methods using Koch structure and T-shaped stub to achieve triple-notch antenna are implemented in three steps. In addition, the effects of T-shaped stub and fractal Koch on the magnitude of the antenna (S11) are studied.

62 citations

Journal ArticleDOI
TL;DR: In this article, two triple-band monopole antennas are proposed for portable wireless applications such as WiFi, WiMAX and WLAN, each printed on a low cost FR-4 substrate.
Abstract: In this paper two triple-band monopole antennas are proposed for portable wireless applications such as WiFi, WiMAX and WLAN. Two different geometrical structures are used for the radiating elements of these antennas, each printed on a low cost FR-4 substrate. Truncated metallic copper ground is used to attain optimum radiation pattern and better radiation efficiency. The frequency of the antennas is reconfigured using a lumped-element switch. The proposed antennas covers three frequency bands 2.45, 3.50 and 5.20 GHz depending upon the switching conditions. Both antennas works with an optimum gain (1.7–3.4 dB), bandwidth (6–35%), VSWR (

59 citations