EEG talk

Talk 1: Metasurface in Radio Astronomy Applications by Dr. Sougata Chatterjee (NCRA, TIFR, Pune)

Abstract: Radio astronomy relies on highly sensitive antenna systems capable of detecting extremely weak celestial signals while operating in increasingly congested electromagnetic environments. Radio frequency interference (RFI), limited receiver sensitivity, and the demand for high-gain, wideband antennas present significant challenges in the design of modern radio telescopes. Metasurfaces, comprising engineered subwavelength electromagnetic structures, have emerged as a promising technology to address these challenges through compact, lightweight, and highly efficient antenna architectures.
 

Talk 2: Multifunctional Metasurfaces towards Advanced Applications by Dr. Somak Bhattacharya (IIT-BHU (Varanasi))

Abstract: Metasurface structures, being ultra-thin in nature has been emerged as applications for various frequency selective surfaces viz., absorber, polarizer, filter, phase-shifter etc. In metasurface based absorbing structures, several sorts of array of metallic patches are designed over a metal-backed dielectric material. The incorporation of metal at the bottom side prohibits the transmission of electromagnetic wave incident to the structure. A number of structures have been proposed over wide band of frequencies ranging from microwave to optical and so forth. Polarization converting structures have also been proposed using metasurface-based designs. In all these designs, asymmetry has been introduced in the unit cell so that the structure is chiral in nature. Both transmittive as well as reflective-type polarization conversion structures using metasurface designs have been reported till date. Very recently, graphene layer has been introduced in the metasurface-based designs to achieve tenability as well as enhancement of bandwidth. By control of applied chemical potential and electrical grating, the plasmonic response of the graphene can be modulated in order to achieve tunability over a wide frequency of incidence. The switching properties in the terahertz domain has been realized using thermal properties of vanadium dioxide.