arXiv subjects

Sasmita Dash

Publications and source records attributed to Sasmita Dash.

7 recordsLinked to original sources

arXiv2025

Sub-6 GHz Beam-Reconfigurable Microfluidic Antenna Using Graphene Liquid for 5G Network

As wireless communication systems continue to grow rapidly, high-performance antennas become increasingly crucial for expanding coverage, improving capacity, and enhancing transmission quality. In light of this, research has focused considerable attention on liquid antennas due to their unique characteristics, which include small size, flexibility, reconfigurability and transparency. Recently, graphene liquid has been explored for numerous applications due to its low cost, high conductivity, flexibility, and ease of processing. Specifically for antenna applications, graphene liquid performs better than conventional liquid metal. This paper presents a graphene-liquid antenna with beam reconfiguration ability for sub-6 GHz communication system. The graphene-liquid movement within the microfluidic channel is taken into consideration by the reconfiguration mechanism. The antenna achieves beam reconfiguration in 360{\deg} directions with 6 dBi of gain at 5.5 GHz, featuring a wideband impedance bandwidth of 24%. The antenna main beam is specifically reconfigured into six directions (0{\deg}, 45{\deg}, 135{\deg}, 180{\deg}, 225{\deg} and 315{\deg}) at 5.5 GHz. Additionally, in all six reconfigurable scenarios at 5.5 GHz, the antenna provides a stable reflection coefficient. Therefore, for the next generation of wireless communication systems, this novel design of graphene-liquid-based reconfigurable sub-6 GHz antennas holds promise.

eess.SP↗

arXiv2025

Tailored Zn(1-x)TixAl2O4 Nanocomposite Particles via Sol-Gel Route for High-Performance Humidity Sensing

Humidity sensors play a vital role in industrial, healthcare, agricultural, and environmental applications; however, conventional sensors often suffer from issues like low sensitivity, slow response, and poor stability. This study investigates sol-gel synthesized Zn0.85Ti0.15Al2O4 nanocomposite ceramics for high-performance humidity sensing. X-ray Diffraction (XRD) analysis confirms a nanocrystalline structure, while the optical bandgap of 3.76 eV indicates the enhanced sensing potential. The sensor exhibits a significant decrease in resistance, from 500 M{\Omega} (15% RH) to 90 M{\Omega}(90% RH), with fast response (50 s) and recovery times (50 s). Low Hysteresis values (5.86% at 30% RH, 7.69% at 60% RH, and 4.28% at 90% RH) highlight high sensitivity, stability, and repeatability. These results indicate the potential of Zn0.85Ti0.15Al2O4as a promising material for next-generation resistive humidity sensors suitable for commercial and industrial deployment.

physics.app-ph↗

arXiv2024

Advancements in Terahertz Antenna Design

The promising way to provide sufficient transmission capacity is by accessing transmission bands at higher carrier frequencies. This desire for higher carrier frequency or more bandwidth led the researchers to take advantage of the terahertz (THz) spectrum. The opportunity for large bandwidth in the THz band leads to the possibility of easy, high data rate transmission. In spite of the advantages, the THz band suffers from large free space path loss. In the development of THz communication systems, the antenna is the most significant component. The focus is especially on designing highly directive antennas because they enhance the performance of the overall system by compensating for the large path loss at THz and thus improving the signal-to-noise ratio. This chapter presents different types of THz antennas, including planar, reflectarray, horn antenna, and lens antenna. Emphasis has been made to present the latest trend of designing THz antennas using carbon-based materials, such as graphene and carbon nanotubes. The performance of these antennas has been compared with that of traditional copper-based THz antennas by critically analyzing their properties. A brief discussion on THz power sources is included in this chapter for completeness. A comprehensive discussion on different fabrication techniques has been provided to appraise the reader of the general fabrication processes of THz components.

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arXiv2020

Nanoantennas Design for THz Communication: Material Selection and Performance Enhancement

In the development of terahertz (THz) communication systems, the nanoantenna is the most significant component. Especially, the focus is to design highly directive antennas, because it enhances the performance of the overall system by compensating the large path loss at THz and thus improves the signal-to-noise ratio. This paper presents suitable material for nanoantenna design and the advancement in their performance for THz communications. Copper, Graphene, and carbon nanotube materials are used as promising candidates for nanoantenna design. The performance of nanoantennas is carried out by analyzing the properties and behavior of the material at THz. Results show that the Graphene nanoantenna provides better performance in terms of miniaturization, directivity, and radiation efficiency. Further, the performance enhancement of the nanoantenna at THz is studied by dynamically adjusting the surface conductivity via the chemical potential of Graphene using the electric field effect. The performance of the nanoantenna is enhanced in terms of high miniaturization, high directivity, low reflection, frequency reconfiguration, and stable impedance. The THz nanoantennas using Graphene have the potential to be used for THz communication systems. In view of the smart THz wireless environment; this paper finally presents a THz Hypersurface using Graphene meta-atoms. The user-side Graphene nanoantennas and environment-side Graphene Hypersurface can build a promising smart THz wireless environment.

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arXiv2020

Graphene Hypersurface for Manipulation of THz Waves

In this work, we investigated graphene hypersurface (HSF) for the manipulation of THz waves. The graphene HSF structure is consists of a periodic array of graphene unit cells deposited on silicon substrate and terminated by a metallic ground plane. The performance of the proposed HSF is numerically analyzed. Electromagnetic parameters of HSF such as permeability, permittivity, and impedance are studied. The proposed graphene HSF has active control over absorption, reflection, and transmission of THz waves. The graphene HSF provides perfect absorption, zero reflection and zero transmission at resonance. Moreover, the graphene HSF structure has the advantage of anomalous reflection and frequency reconfiguration. Incident waves can be reflected in the desired direction, depending on the phase gradient of the HSF and the perfect absorption is maintained at all reconfigurable frequencies upon reconfiguration. The results reveal the effectiveness of the graphene HSF for the manipulation of THz waves.

eess.SP↗

arXiv2020

Impact of Graphene Thickness on EM Modelling of Antenna

This paper presents illustrative electromagnetic modelling and simulation of graphene antenna using a two-dimensional graphene sheet of zero thickness and a three-dimensional graphene slab of finite thickness. The properties of the antenna are analyzed in terms of the S11 parameter, input impedance, VSWR, radiation pattern, and frequency reconfiguration using the full-wave electromagnetic simulator. Furthermore, this work numerically studies the modelling of graphene antenna using a three-dimensional graphene thin slab and the impact of graphene slab thickness on the performance of graphene antenna.

physics.app-ph↗

arXiv2019

Wideband Perfect Absorption Polarization Insensitive Reconfigurable Graphene Metasurface for THz Wireless Environment

In this work, we investigated a simple structured graphene terahertz (THz) metasurface (MSF) with perfect absorption, wideband, polarization insensitive, oblique incidence insensitive and frequency reconfiguration. The graphene MSF structure is composed of a two-dimensional periodic array of graphene meta-atoms deposited on the silicon substrate terminated by a metal ground plane. The performance of the proposed MSF is numerically analyzed. An equivalent circuit model of the structure and its closed-form solution is introduced. The graphene MSF thin structure at 2.5 THz provides 100% of absorption with wide bandwidth, zero reflection and zero transmission at normal incidence in both transverse electric (TE) and transverse magnetic (TM) polarization. Under oblique incidence, the absorption is maintained at higher than 95%. Moreover, the graphene MSF structure has the advantage of frequency reconfiguration. The excellent absorption performance is maintained at all reconfigurable frequencies upon reconfiguration. The results reveal the effectiveness of the THz MSF with graphene meta-atoms, which can be promising for THz wireless environment.

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