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Rajesh Natarajan

Bio: Rajesh Natarajan is an academic researcher from VIT University. The author has contributed to research in topics: Radiation pattern & Vivaldi antenna. The author has an hindex of 10, co-authored 18 publications receiving 383 citations. Previous affiliations of Rajesh Natarajan include Valliammai Engineering College & Anna University.

Papers
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Journal ArticleDOI
TL;DR: The proposed approach uses a metamodeling technique and performance analysis and tuning as well as a middleware infrastructure that enable practical sensor grid implementation and management.
Abstract: Sensor grid is a platform that combines wireless sensor networks and grid computing with the aim of exploiting the complementary advantages of the two systems. Proper integration of these distinct systems into effective, logically single platform is challenging. This paper presents an approach for practical sensor grid implementation and management. The proposed approach uses a metamodeling technique and performance analysis and tuning as well as a middleware infrastructure that enable practical sensor grid implementation and management. The paper presents our implementation and analysis of the sensor grid.

3 citations

Journal ArticleDOI
TL;DR: A novel ellipsoid slot array integrated with the compact MIMO antenna accomplishes the increasing demand of customers with 4G and 5G application bands.
Abstract: A novel ellipsoid slot array integrated with the compact MIMO antenna accomplishes the increasing demand of customers with 4G and 5G application bands. The proposed antenna incorporates a front FR4 layer holding a planar radiator, ground plane etched with ellipsoid slot array and back FR4 layer with the corporate feed network. The corporate feed network delivers power to the framework of 2 × 4 matrix ellipsoid slot array in the ground plane. The front and the back FR4 layer are detached by the ground plane, which acts as both radiator as well as isolator. The ground plane containing ellipsoid slot array antenna resonates at 17 GHz. It also provides 25 dB isolation in the LTE application bands. This antenna arrangement achieves the impedance bandwidth of 600 MHz (2–2.6) GHz for LTE 2300 MHz, LTE 2500 MHz and 2 GHz (15–17) GHz for 17 GHz 5G application band. Apart from this, the simulated gain of 3.33/4.67/7.5 dBi and measured gain of 3.01/4.58/7.3 dBi is achieved for resonating frequencies such as 2.3/2.5/17 GHz. High efficiency of 84/91/90% is obtained for microwave and millimeter wave frequencies. Envelope correlation coefficient evaluated from the radiation pattern is found to be < 0.5.

3 citations

Journal ArticleDOI
TL;DR: This paper aims at implementing an efficient sensor middleware for maintaining and managing big data and analysing the efficiency of such a sensormiddleware.
Abstract: This paper aims at implementing an efficient sensor middleware for maintaining and managing big data and analysing the efficiency of such a sensor middleware. The work focused on designing of sensor middleware and performance analysis of the sensor middleware. The Hadoop framework, which was used as a sensor middleware, was responsible for maintaining and managing the distributed sensor environment. A prominent monitoring tool such as Zabbix was used to monitor the Hadoop processes and provide alerts for custom trigger events. Performance analysis for the sensor middleware such as Hadoop was done using tools such as collectl and colplot. Performance analysis of Hadoop cluster was performed using an evaluation metric such as total runtime of the job. A brief discussion on the Hadoop tuning tool such as starfish, that makes the Hadoop cluster efficient through configuration changes, is also presented.

1 citations

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TL;DR: In this article , the authors analyzed the role of structural change in explaining growth accelerations and decelerations in Indian states over the 30 years from 1980-1981 to 2010-2011.
Abstract: This article analyses the role of structural change in explaining growth accelerations and decelerations in Indian states over the 30 years from 1980–1981 to 2010–2011. We employ conventional shift-share analysis to measure the sectoral contribution to productivity growth. We apply this methodology to an eight-sector data set for 15 major states. Our results show that productivity changes ‘within’ sectors explain the considerable improvement in productivity in Indian states rather than the reallocation of labour to more productive sectors. At the aggregate level and for several states, significant contribution to productivity improvements has emanated from agriculture, trade and manufacturing sectors. In all these sectors, the main contribution emerged from within sector productivity improvements, not from structural changes. However, the reallocation effect has appeared to deliver marginal gains to overall productivity in recent periods, which is evident for construction, manufacturing, trade and services sectors. JEL Classification: O10, O40, O47, R11
Journal ArticleDOI
TL;DR: In this article , the authors examine the patterns and correlates of the productivity gap between male and female-owned enterprises in India's informal sector and find that female owned firms are 45 per cent less productive than male-owned firms on average, with the greatest productivity gaps observed at the lower end ofthe productivity distribution.

Cited by
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Journal ArticleDOI
TL;DR: In this article, an efficient approach to achieve the shielding effectiveness (SE) by using a frequency-selective surface (FSS) is presented, which consists of cross dipoles and rings printed on the opposite sides of a single-layer FR-4 substrate, exhibits a wide, 7.5GHz stopband to provide simultaneous shielding in both X and Ka-bands.
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.

190 citations

Journal ArticleDOI
TL;DR: A representative architecture of CAVs is introduced and the latest research advances, methods, and algorithms for sensing, perception, planning, and control of CAV are surveyed and their significant research issues enumerated.
Abstract: Autonomous vehicle (AV) technology can provide a safe and convenient transportation solution for the public, but the complex and various environments in the real world make it difficult to operate safely and reliably. A connected autonomous vehicle (CAV) is an AV with vehicle connectivity capability, which enhances the situational awareness of the AV and enables the cooperation between AVs. Hence, CAV technology can enhance the capabilities and robustness of AV to be a promising transportation solution in the future. This paper introduces a representative architecture of CAVs and surveys the latest research advances, methods, and algorithms for sensing, perception, planning, and control of CAVs. It reviews the state-of-the-art and state-of-the-practice (when applicable) of a multi-layer Perception-Planning-Control architecture including on-board sensors and vehicular communications, the methods of sensor fusion and localization and mapping in the perception layer, the algorithms of decision making and trajectory planning in the planning layer, and the control strategies of trajectory tracking in the control layer. Furthermore, the implementations and impact of vehicle connectivity and the corresponding consequential challenges of cooperative perception, complex connected decision making, and multi-vehicle controls are summarized and their significant research issues enumerated. Most importantly, the critical review in this paper provides a list and discussion of the remaining challenges and unsolved problems of CAVs in each Section which would be helpful to researchers in the field. The comprehensive coverage of this paper makes it particularly useful to academic researchers, practitioners, and students alike.

161 citations

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TL;DR: In this article, a dual-band wearable fractal-based monopole patch antenna integrated with an electromagnetic band-gap (EBG) structure is presented for the GSM-1800 MHz and ISM-2.45 GHz bands.
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.

160 citations

Journal ArticleDOI
TL;DR: In this article, a review of recent developments in the field of frequency selective surface (FSS)-based advanced electromagnetic (EM) structures is presented, which is a type of filter consisting of an array of periodic metallic patches or apertures on a dielectric substrate.

134 citations

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TL;DR: A new, portable, and low-cost microwave imaging (MWI) system using an iterative enhancing technique for breast imaging that has been able to perform the detection of tumorous cells in breast phantom that can pave the way to saving lives.
Abstract: Globally, breast cancer is a major reason for female mortality. Due to the limitations of current clinical imaging, the researchers are encouraged to explore alternative and complementary tools to available techniques to detect the breast tumor in an earlier stage. This article outlines a new, portable, and low-cost microwave imaging (MWI) system using an iterative enhancing technique for breast imaging. A compact side slotted tapered slot antenna is designed for microwave imaging. The radiating fins of tapered slot antenna are modified by etching nine rectangular side slots. The irregular slots on the radiating fins enhance the electrical length as well as produce strong directive radiation due to the suppression of induced surface currents that radiate vertically at the outer edges of the radiating arms with end-fire direction. It has remarkable effects on efficiency and gain. With the addition of slots, the side-lobe levels are reduced, the gain of the main-lobe is increased and corrects the squint effects simultaneously, thus improving the characteristics of the radiation. For experimental validation, a heterogeneous breast phantom was developed that contains dielectric properties identical to real breast tissues with the inclusion of tumors. An alternative PC controlled and microcontroller-based mechanical MWI system is designed and developed to collect the antenna scattering signal. The radiated backscattered signals from the targeted area of the human body are analyzed to reveal the changes in dielectric properties in tissues. The dielectric constants of tumorous cells are higher than that of normal tissues due to their higher water content. The remarkable deviation of the scattered field is processed by using newly proposed Iteratively Corrected Delay and Sum (IC-DAS) algorithm and the reconstruction of the image of the phantom interior is done. The developed UWB (Ultra-Wideband) antenna based MWI has been able to perform the detection of tumorous cells in breast phantom that can pave the way to saving lives.

111 citations