Manoharan Ramkumar Raja

This paper presents a novel optical fiber with a hollow core and metamaterial cladding formed with a chalcogenide material (Sb ₂ Te ₃ ), which is analyzed in the visible spectrum. The fiber investigates the mode propagation based on the dual-phase property of Sb ₂ Te ₃ . This study enables multi-parameter optimization, including cladding composition for metamaterial, core geometry and different phase states. Here, the results are obtained in terms of effective mode index, confinement loss, power confinement and dispersion. The proposed fiber exhibits a loss of 0.39[ ]dB/m with a maximum of 99% power confinement in the guiding region. A comparatively lower confinement loss and increased mode stability are achieved than in other chalcogenide-only cladding structures. The proposed fiber presents a cutting-edge integration of material and structural study to enable electromagnetic response manipulation, which paves the way for next-generation optical fiber in the visible spectrum.

This study presents a biosensor architecture that integrates graphene with silver and bismuth in a multi-resonator architecture optimized for glucose detection. This work uniquely integrates graphene with silver and bismuth in a multi-resonator SPR configuration, demonstrating unprecedented sensitivity and linearity for non-invasive glucose detection. Unlike previous single-material or binary-material approaches, our design introduces a three-metal hybrid architecture (Ag/Bi/Au) combined with graphene in a geometrically optimized multi-resonator array specifically engineered for terahertz glucose sensing. Computational electromagnetic simulations using finite element methods reveal that the sensor achieves a sensitivity of 2000 GHz RIU⁻¹ within the refractive index range of 1.335–1.347, which is particularly suitable for glucose monitoring applications. Key parameters including graphene chemical potential, angle of incidence, and resonator dimensions were systematically varied to optimize performance, with the sensor exhibiting a quality factor of approximately 10.8 and a figure of merit reaching 27.778 RIU⁻¹. The relationship between resonance frequency and refractive index demonstrates strong linearity (R² = 85%). Additionally, a stacking ensemble regression model was developed to predict absorption characteristics, achieving prediction accuracy up to 100% for certain parameter ranges. This research advances the development of high-performance terahertz biosensors for non-invasive glucose monitoring with potential applications in diabetes management.

This paper presents a novel co-design approach for wireless applications, integrating mm-wave and microwave technologies. The design features two antennas where a slotted waveguide array is fabricated using 3D-printing technology with an AlMg10Si alloy resonating at mm-wave frequency band, while a printed monopole antenna resonating at microwave frequency band shares a common ground plane with the slotted waveguide array. The electrically small printed monopole is realized on an FR4 substrate, is suitable for WLAN bands, and achieves ease of integration with the antenna at the Ka-band owing to the low profile. The co-design approach is particularly advantageous for wireless applications as it enables the seamless integration of different frequency bands, enhancing system versatility and performance. The antenna achieves dual frequency band operation covering the Impedance bandwidth of 15.27% (5.08-5.92) and 14.56% (26.48-30.64) at microwave and Ka-band frequencies, respectively. The innovative use of materials and advanced fabrication techniques also underscores the design's potential for diverse high-performance wireless applications.