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Author

D. Thiripurasundari

Bio: D. Thiripurasundari is an academic researcher from VIT University. The author has contributed to research in topics: Antenna (radio) & Dipole antenna. The author has an hindex of 5, co-authored 16 publications receiving 84 citations.

Papers
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Journal ArticleDOI
TL;DR: A detailed analysis on the design issues such as antenna miniaturization, integration issues, antenna coupling and isolation enhancement techniques are presented and better isolation is achieved using meta materials, decoupling networks and defected ground structures.
Abstract: Objectives: Presently, wireless applications are quickly moving towards multiple input multiple output configuration, thereby the quest for integration of many antennas in the user’s equipment enhanced. A MIMO Antenna is used as a reason of enhancing the capacity of the channel without the need of additional power or frequency band. It requires many antennas set up in the transmitter with less coupling between them. Methods/Statistical Analysis: Hence, for an effective MIMO antenna system mutual coupling between the antennas should be low. Various MIMO antenna designs have been reported by antenna researchers for wireless application. The main design challenge in MIMO antennas is to attain high isolation amid the antenna elements. This paper reviews various isolation techniques proposed in the recent years. A detailed analysis on the design issues such as antenna miniaturization, integration issues, antenna coupling and isolation enhancement techniques are presented. Findings: among the isolation methods discussed better isolation is achieved using meta materials, decoupling networks and defected ground structures. Application: MIMO antenna systems find application in portable devices, automotive applications, handheld devices, personal digital assistant etc.

44 citations

Journal ArticleDOI
TL;DR: Performance of various techniques in terms accuracy, memory and computational time for application specific tasks such as modeling RCS (Radar cross section), space applications, thin wires, antenna arrays are presented.
Abstract: Computational electromagnetics (CEM) is applied to model the interaction of electromagnetic fields with the objects like antenna, waveguides, aircraft and their environment using Maxwell equations. In this paper the strength and weakness of various computational electromagnetic techniques are discussed. Performance of various techniques in terms accuracy, memory and computational time for application specific tasks such as modeling RCS (Radar cross section), space applications, thin wires, antenna arrays are presented in this paper.

31 citations

Proceedings ArticleDOI
03 Apr 2013
TL;DR: In this article, the second iteration version of Koch fractal antenna is applied to a Dipole antenna to get second iteration versions of Koch Fractal antenna for 450MHZ and the Koch geometry is used to reduce the overall size of the antenna.
Abstract: In this paper, Koch iteration Technique is applied to a Dipole antenna to get second iteration version of Koch fractal antenna. The performance properties of Koch fractal Dipole for 450MHZ have been primarily indicated to its fractal geometry. The Koch geometry is used to reduce the overall size of the antenna. The size of designed Antenna is reduced around 32% compared to conventional dipole at designed frequency. The Koch fractal antenna is designed, fabricated and characterized on a wearable (jeans) substrate. Simulations are done in CST MICROWAVE STUDIO.

14 citations

Journal ArticleDOI
TL;DR: In this article , the authors have synthesized calcium doped nickel ferrite (Ni 1-x Ca x Fe 2 O 4 (0 ≤ x ≤ 0.5)) nanoparticles by microwave combustion technique and its degradation has been studied using one of the most harmful dye rhodamine B (RhB), by means of enhanced visible light photocatalytic degradation.

12 citations

Proceedings ArticleDOI
11 Apr 2013
TL;DR: In this article, a triple band bow-tie wearable antenna is designed to operate at 450 MHz, 800 MHz and 1.4 GHz, and a study on most commonly used textile substrates are carried out and it is found that jeans cotton provides maximum S11.
Abstract: A novel triple band bow-tie wearable antenna is designed to operate at 450 MHz, 800 MHz and 1.4 GHz. Electro-Textile materials were used as the substrate in order to provide higher degree of flexibility. A study on most commonly used textile substrates are carried out and it is found that jeans cotton provides maximum S11. Specific absorption rate (SAR) of the designed antenna is calculated using the voxel model. The calculated SAR value agrees with the international standards.

10 citations


Cited by
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Journal ArticleDOI
TL;DR: The performances of the proposed antenna by the simulation and experimentation equally designated it a blameless candidate for the UWB applications.
Abstract: In this communication, a compact two-element ultra-wideband (UWB) wearable multiple-input multiple-output (MIMO) antenna with high port isolation is presented. The proposed structure is composed of jeans material in which an `8' shaped stub is placed on the middle position of the antenna backside and connected to the partially suppressed ground structure to improve the port isolation characteristics. The antenna covers the frequency range from 2.74 to 12.33 GHz (about 127.27%) with the port isolation of >26 dB over the entire UWB frequency range. The envelope correlation co-efficient is found to be 9.9) throughout the complete operating band. The channel capacity loss for the proposed MIMO antenna is <;0.13 bit/s/Hz. The imprinted optimised UWB MIMO antenna covers the area size of 55 × 35 mm 2 . The performances of the proposed antenna by the simulation and experimentation equally designated it a blameless candidate for the UWB applications.

74 citations

Journal ArticleDOI
TL;DR: In this paper, the authors proposed a multiple antenna system for 5G smartphones operating at 3.5 GHz for multiple-input multiple-output (MIMO) operation in smartphones, which adopted the unit open-end slot antenna fed by Inverted-L microstrip with tuning stub.
Abstract: In this paper, the systematic design of a multiple antenna system for 5G smartphone operating at 3.5 GHz for multiple-input multiple-output (MIMO) operation in smartphones is proposed. The smartphone is preferred to be lightweight, thin, and attractive, and as a result metal casings have become popular. Using conventional antennas, such as a patch antenna, Inverted-F antennas, or monopole, in proximity to metal casing leads to decreasing its total efficiency and bandwidth. Therefore, a slot antenna embedded in the metal casing can be helpful, with good performance regarding bandwidth and total efficiency. The proposed multiple antenna system adopted the unit open-end slot antenna fed by Inverted-L microstrip with tuning stub. The measured S-parameters results agree fairly with the numerical results. It attains 200 MHz bandwidth at 3.5 GHz with ports isolation of (≤−13 dB) for any two antennas of the system. The influence of the customer’s hand for the proposed multiple antenna system is also considered, and the MIMO channel capacity is computed. The maximum achievable MIMO channel capacity based on the measured result is 31.25 bps/Hz and is about 2.7 times of 2 × 2 MIMO operation.

57 citations

Journal ArticleDOI
TL;DR: The results in this paper explained that the HDR panorama images that resulting from the proposed method is more realistic image and appears as it is a real panorama environment.
Abstract: This paper presents a methodology for enhancement of panorama images environment by calculating high dynamic range. Panorama is constructing by merge of several photographs that are capturing by traditional cameras at different exposure times. Traditional cameras usually have much lower dynamic range compared to the high dynamic range in the real panorama environment, where the images are captured with traditional cameras will have regions that are too bright or too dark. A more details will be visible in bright regions with a lower exposure time and more details will be visible in dark regions with a higher exposure time. Since the details in both bright and dark regions cannot preserve in the images that are creating using traditional cameras, the proposed system have to calculate one using the images that traditional camera can actually produce. The proposed systems start by get LDR panorama image from multiple LDR images using SIFT features technology and then convert this LDR panorama image to the HDR panorama image using inverted local patterns. The results in this paper explained that the HDR panorama images that resulting from the proposed method is more realistic image and appears as it is a real panorama environment.

55 citations

Journal ArticleDOI
TL;DR: In this paper, decoupling network isolation approach, parasitic element approach, defected ground structure, Neutralization line, isolation improvement based on metamaterials, isolation improved using PIN diode, varactor diode and feeding structure have been incorporated, and their merits and demerits have been discussed.
Abstract: The present technology fulfills the requirement of high data rate and high channel capacity using multiple input multiple output (MIMO) technology. The MIMO capacity of the system is increased linearly but due to the multiple antennas placed near to each other, problem of mutual coupling exists, which degrades the maximum achievable performance of the system. The problems of multipath propagation can be solved using MIMO system. The isolation improvement methods decrease the mutual coupling among antenna elements, and improve the gain and efficiency of the system. In this paper, decoupling network isolation approach, parasitic element approach, defected ground structure, Neutralization line, isolation improvement based on metamaterials, isolation improvement using PIN diode, varactor diode, and feeding structure have been incorporated, and their merits and demerits have been discussed. The effect of different permittivity material on antenna parameters has also included.

53 citations

Journal ArticleDOI
TL;DR: In this article, the authors review the resonant behavior of spin ices (which is in the GHz frequency range), focusing on their potential application as magnonic crystals, and discuss experimental, theoretical, and numerical methods for determining the spectral response of artificial spin icicles, and give an outlook on new directions for reconfigurable spin ice.
Abstract: Over the past few years, the study of magnetization dynamics in artificial spin ices has become a vibrant field of study. Artificial spin ices are ensembles of geometrically arranged, interacting magnetic nanoislands, which display frustration by design. These were initially created to mimic the behavior in rare earth pyrochlore materials and to study emergent behavior and frustration using two-dimensional magnetic measurement techniques. Recently, it has become clear that it is possible to create artificial spin ices, which can potentially be used as functional materials. In this Perspective, we review the resonant behavior of spin ices (which is in the GHz frequency range), focusing on their potential application as magnonic crystals. In magnonic crystals, spin waves are functionalized for logic applications by means of band structure engineering. While it has been established that artificial spin ices can possess rich mode spectra, the applicability of spin ices to create magnonic crystals hinges upon their reconfigurability. Consequently, we describe recent work aiming to develop techniques and create geometries allowing full reconfigurability of the spin ice magnetic state. We also discuss experimental, theoretical, and numerical methods for determining the spectral response of artificial spin ices, and give an outlook on new directions for reconfigurable spin ices.

48 citations