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Your search keyword '"Chakyar, Sreedevi P"' showing total 26 results
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26 results on '"Chakyar, Sreedevi P"'

3. Complex permittivity measurement using metamaterial split ring resonators.

Author

Chakyar, Sreedevi P., Simon, Sikha K., Bindu, C., Andrews, Jolly, and Joseph, V. P.

Subjects
*PERMITTIVITY, *MICROWAVE frequency converters, *FREQUENCY changers, *DIELECTRIC properties, *QUANTUM perturbations
Abstract

A direct and efficient method for determining the complex permittivity of materials at microwave frequencies using a Split Ring Resonator (SRR) metamaterial structure is presented. A single SRR unit fabricated on a substrate arranged between transmitting and receiving probes acts as a test probe. Dielectric samples having at least one flat surface of area greater than or equal to the area of SRR structure are used as test samples. The relative permittivity and the loss tangent of the dielectric are evaluated from the resonant frequency shift and the bandwidth of the SRR resonator, by placing the sample over it. The LC resonance of the SRR test probe is theoretically related to the permittivity by considering its equivalent circuit in terms of the dielectric filled capacitances formed on the upper and lower surfaces of the SRR. The permittivity measurements are performed using test probes of different resonant frequencies, and the results are compared with the values obtained by the cavity perturbation method. [ABSTRACT FROM AUTHOR]

Published
2017
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12. Microwave absorption properties of flexible zinc oxide sheet

Author

Paul, Nees, primary, Jimmy, Janet, additional, Chakyar, Sreedevi P., additional, Simon, Sikha K., additional, Kizhakooden, Joe, additional, Bindu, C., additional, Sebastian, Anju, additional, Umadevi, K. S., additional, Jose, Jovia, additional, Andrews, Jolly, additional, and Joseph, V. P., additional

Published
2019
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19. Interaction of a Sine Wave with an Artificial Negative Permittivity Medium Using Nonstandard FDTD.

Author

Jovia, Jose, Simon, Sikha K., Kizhakooden, Joe, Sebastian, Anju, Chakyar, Sreedevi P., Paul, Nees, Bindu, Cherala, Andrews, Jolly, and Joseph, Vallikkavumkal P.

Subjects
SINE waves, PERMITTIVITY, MASS media use, FINITE differences, PLASMA frequencies, FINITE difference time domain method
Abstract

This paper presents the realization of Nonstandard Finite Difference Time Domain (NS-FDTD) analysis having high accuracy and low computational cost to a negative permittivity metamaterial wire medium for the first time. A sine wave of frequency less than that of plasma frequency of the medium which is in the shape of a slab reflector is allowed to interact after identifying the exact values of the required stability condition of the NS-FDTD. The electric field distribution around the plasma slab obtained for a particular excitation point using NS-FDTD and standard FDTD are demonstrated which show obvious advantages of this high accuracy algorithm. This novel technique may be further extended to various dispersive and metamaterial structures. [ABSTRACT FROM AUTHOR]

Published
2019
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20. Metamaterial inspired featherlight artificial plasma horn antenna for astronomical and communication applications.

Author

Kizhakooden, Joe, Jose, Jovia, Paul, Nees, Simon, Sikha K., Chakyar, Sreedevi P., Andrews, Jolly, and Joseph, V. P.

Subjects
METAMATERIAL antennas, ANTENNA design, PLASMA antennas, HORN antennas, PERMITTIVITY, METALLIC wire, ANTENNA radiation patterns, ASTRONOMICAL research
Abstract

In this article, we introduce a novel type of horn antenna constructed using artificial plasma sheets. This metamaterial inspired negative permittivity antenna fabricated using thin metallic wires in a specialized manner is observed to have same radiation performance of an equivalent conventional metallic horn structure. This novel plasma antenna can replace the conventional one in all microwave applications. The featherlight weight and the ability to remove the problems related with wind resistance and rain accumulation of this new structure may result in a rethinking of the use of horn antennas in astronomical data collection. [ABSTRACT FROM AUTHOR]

Published
2019
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