V. K. Hariharan

SRM Institute of Science and Technology

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Co-Authors

R. Renuka

Indian Space Research Organisation

P.V.N. Murthy

Indian Space Research Organisation

Vaddi Raghavaiah

Indian Space Research Organisation

S. S. Kumar

Indian Space Research Organisation

S.V.K. Shastry

Indian Institute of Science Bangalore

N.D. Ghatpande

Indian Space Research Organisation

V.R. Katti

Indian Space Research Organisation

T.L. Danabalan

Indian Space Research Organisation

Puneet Kumar Mishra

Indian Space Research Organisation

Satish Kumar Bandlamudi

Indian Space Research Organisation

Cooperative Institutions

Indian Space Research Organisation

Applied Materials (United States)

University of Florida

Andhra University

Bangalore Medical College and Research Institute

Amrita Vishwa Vidyapeetham

Government of India

Vellore Institute of Technology University

SRM Institute of Science and Technology

Anna University, Chennai

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Magnetic Compatibility Studies of Bus Bar and Magnetic Torquer in GSAT-19

Varla Ashok Kumar Pallavi Yarlagadda Vaddi Raghavaiah P.V.N. Murthy R. Renuka

In GSAT-19 spacecraft, one of the magnetic torquer is located very near to the bus bar. The objective of this study is to estimate the DC magnetic field generated by bus bar at magnetic torquer location and verify the magnetic compatibility between busbar and torquer. The modelling and simulation are carried out with the help of Computer Simulation Technology (CST) software. Magneto static solver [3] is used to find out the Magnetic field at magnetic torquer location in spacecraft. The magnetic field values estimated from the simulations are compared with the experimentally measured values.

Busbar

Solver

Electromagnetic Compatibility

10.1109/incemic.2018.8704617

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Citations (0)

Comments on "AC impedance of an isolated flat conductor"

IEEE Transactions on Electromagnetic Compatibility (2003)

V. K. Hariharan S.V.K. Shastry

For original paper see Z. Zhihua and M. Weiming, IEEE Trans. Electromagn. Compat., vol.44, pp.482-486, (2002). Employing the moments method, and a triangular patch modeling technique, this paper gives an analysis of the AC impedance of an isolated flat conductor, taking into consideration capacitive effects. It is observed that, for the flat conductor under consideration, the capacitance has a significant effect on the impedance beyond a frequency of about 20 MHz. Thus, it can be concluded that the capacitive effects should also be considered in evaluating the AC impedance of an isolated conducting strip.

10.1109/temc.2003.819067

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Citations (2)

Estimation of Free Space Capacitance and Body Potential of a Spacecraft for Charging Analysis

IEEE Transactions on Plasma Science (2013)

B. Karthikeyan V. K. Hariharan Subrata Sanyal

This paper presents a computation of the absolute free space capacitance and electrostatic body potential of a spacecraft using moment method with triangular patch modeling. Expressions are derived numerically and the moment integral is evaluated. The capacitance of a square plate is computed to validate the approach. Finally, the free space capacitance of a typical spacecraft is computed for various configurations and body potential is evaluated. The derived expressions are simple and suitable for developing the charging analysis tool. As this approach is more general, it can be easily applied to any practical spacecraft configuration.

Spacecraft charging

10.1109/tps.2013.2271280

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Citations (17)

Mitigation techniques followed in electrical integration of scanning Sky monitor payload

Ch. Phanendra Rao G. Bhooma S. M. Muniraj S. T. Nandish Jeyanthi Rajesh

ASTROSAT is a scientific mission aimed at providing space based multi-wavelength observatory in the frontier areas of astronomy. It carries scientific instruments sensitive over a wide spectrum of wavelengths covering Visible, Ultra Violet, Soft X-rays and Hard X-rays over an energy band of 2-100keV. It accommodates five payloads to perform the task. Scanning Sky monitor (SSM) is one of the payloads designed to measure the soft X-rays over a band of 2-10keV for transient events. Electrical integration of SSM payload poses huge challenges in the form of design and implementation of electrical distribution system for rotating mechanism, grounding of electronics packages on Carbon Fibre Reinforced Plastic (CFRP) platform, problems faced during the testing in dis-assembled mode and measures taken to overcome the same. This paper discusses the above mentioned aspects from the perspective of electrical integration and testing.

Payload (computing)

10.1109/incemic.2016.7921481

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Effect of Chamber Conditions and Substrate Type on PECVD of SiGeSn Films

Crystal Structure Theory and Applications (2021)

V. K. Hariharan Jignesh Vanjaria Arul Chakkaravarthi Arjunan Gary S. Tompa Hongbin Yu

In the past studies have shown that the addition of Ge and Sn into Si lattice to form SiGeSn enhances its carrier mobility and band-gap properties. Conventionally SiGeSn epitaxial films are grown using Ultra-High Vacuum (UHV) conditions with pressures ranging from 10-8 torr to 10-10 torr which makes high volume manufacturing very expensive. On the contrary, the use of low-pressure CVD processes (vacuum levels of 10-2 torr to 10-4 torr) is economically more viable and yields faster deposition of SiGeSn films. This study outlines the use of a cost-effective Plasma Enhanced Chemical Vapor Deposition (PECVD) reactor to study the impact of substrate temperature and substrate type on the growth and properties of polycrystalline SiGeSn films. The onset of polycrystallinity in the films is attributed to the oxygen-rich PECVD chamber conditions explained using the Volmer-Weber (3D island) mechanism. The properties of the films were characterized using varied techniques to understand the impact of the substrate on film composition, thickness, crystallinity, and strain.

Torr

10.4236/csta.2021.103004

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Citations (3)

Charging analysis of GSAT-17 patch antenna

R. Renuka P.V.N. Murthy Vaddi Raghavaiah P. Sowjanya Varia Ashok Kumar

GSAT-17 spacecraft is one of the most complicated and technologically advanced Satellites being built by Indian Space Research Organisation (ISRO). The payload configuration of GSAT-17 spacecraft is 24 channels In Normal C-Band Transponders, 12 channels in Upper Ext. C-Band Transponders, 2 Channels in Lower Extended C transponders, 2 Channels each in MSS and DRT/SAR. For Lower Ext-C band, 0.75m × 0.77m Tx./Rx. patch array (8×4) antenna is designed for both uplink and downlink signals. This antenna is mounted on EV top of the satellite and provides coverage to southern Indian peninsula and Antarctica. This poses a charging threat, if not properly grounded, due to GEO spacecraft charging. Hence a good grounding scheme is necessary for ESD compliance. A study was taken up to assess the surface and internal charging effects on the antenna and proper grounding scheme was worked out to mitigate this problem.

Payload (computing)

10.1109/incemic.2016.7921508

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Modular Power System and bus bar scheme in high power communication satellite

Vivek Rai Srivastava Prem Poddar B Veena Soma V Chetty V. Lakshminarayana

This paper elaborates implementation of new and advanced concepts such as Modular Power System and bus bar scheme for power distribution in ISRO's high power communication satellite. The advantages of using Modular Power System vs. conventional power packages, details of new design and realization of Modular Power System are discussed. New mechanical housings realized for high power communication satellite are described. Usage of bus bar for power distribution has many advantages (as compared to wired harness) such as, reduced power distribution loss, higher current carrying capability, improved EMC performance, better thermal management and scope for mass reduction.

Busbar

Power module

Communications satellite

Power budget

10.1109/edaps.2014.7030819

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Citations (6)

Development of circuit model for spacecraft charging studies

V. K. Hariharan S.V.K. Shastry Arindam Chakraborty V.R. Katti

The external surfaces of a spacecraft exposed to Earth's magnetospheric plasma can build up differential voltages which can result in an electrostatic discharge (ESD). This discharge may induce transient electromagnetic interference (EMI) in the electronics circuitry and may give rise to switching anomalies or system failure under certain environmental conditions. This paper outlines the development of circuit model of a spacecraft for surface charging studies by assuming Maxwellian distribution function to represent the plasma particles in space. Analytical expressions for charging and discharging current sources of the geosynchronous Earth orbit (GEO) plasma have been obtained. A numerical solution procedure using method of moments and triangular patch modelling to determine the capacitance of conducting objects in free space has been developed. Differential equations of spacecraft charging have been derived and the surface charging of INSAT-2E spacecraft has been simulated.

Spacecraft charging

Transient (computer programming)

Orbit (dynamics)

Debye sheath

10.1109/icemic.1999.871604

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Citations (3)

Neuro cognitive activator

Materials Today Proceedings (2021)

V. Akila J. Anita Christaline V. S. Thinesh V. K. Hariharan

Functional near-infrared spectroscopy

Verbal fluency test

10.1016/j.matpr.2021.07.282

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The continuing challenge of spacecraft ESD

International Conference on Electromagnetic Interference and Compatibility (2006)

V. K. Hariharan M. Nageswara Rao S.V.K. Shastry N.D. Ghatpande T.L. Danabalan

The threat of spacecraft electrostatic discharge (ESD) arises primarily from the energetic charged particles (electrons and ions) present in the magnetospheric plasma of the earth, at the altitudes of geo-synchronous satellites. The charged particles in the energy range, less than 50 keV, give rise to surface charging and those in the higher energy range (> 100 keV) penetrate into the interiors of the spacecraft and give rise to deep dielectric (internal) charging. Under certain circumstances, the charge accumulation continues until the dielectric breaks down electrically, producing effects such as material destruction, contamination of nearby surfaces, or electrostatic discharge. The discharge may induce transient electromagnetic interference (EMI) in the electronic circuitry and may give rise to switching anomalies or failure of the system under severe environmental condition. This paper describes the spacecraft charging, surface charging as well as internal charging studies that have been carried out. Techniques of hardening the spacecraft subsystems against on-board ESD are outlined. The point made is that spacecraft ESD threat has not gone away, and the relevant satellite specifications are becoming increasingly stringent, constituting a continuing major challenge for spacecraft designers and system integrators.

Spacecraft charging

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