Faculty Publications
Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736
Publications by NITK Faculty
Browse
18 results
Search Results
Item A novel beam steering dipole antenna using phase varying metasurface as reflector(Institute of Electrical and Electronics Engineers Inc., 2018) Majumder, B.; Mukherjee, J.; Kandasamy, K.; Ray, K.P.In this paper a simulation based study of a novel continuously beam steerable antenna is presented using a tunable metasurface as phase varying reflector. The antenna radiation pattern can be changed by changing the state of the diodes loaded in the phase varying reflector. A planar dipole antenna is used to excite the tunable reflector. By this technique the antenna beam can be steered from +300 to -300 in the broadside direction depending on the operating state of the diodes. Moreover, the state of the diodes can be addressed digitally and hence a steep gradient in phase can be achieved in the reflector. The antenna radiation pattern and the gain has been found stable all over its states. © 2017 IEEE.Item Dual-Functional Metasurface Reflector for Wideband Polarization Conversion and RCS Reduction Applications(Institute of Electrical and Electronics Engineers Inc., 2023) Goud, M.; Kandasamy, K.; Majumder, B.A wideband polarization transforming reflective metasurface with dual functionality is proposed in this work. It converts the incident TE(Transverse Electric)/TM(Transverse Magnetic) waves into circularly polarized waves in a portion of the operating band and also into TM/TE waves respectively waves at the remaining frequency spectrum. The proposed unit cell's front side comprises of tapered rectangular metal connected with a circular patch and backside by a metal ground. Proposed structure exhibits circular polarization (CP) conversion from 13.5-20.9 GHz and cross polarization (XP) conversion from 11.12-12.64 and 23.32-34.65 GHz. The proposed meta-atom and 90 degree rotated image are used to construct checkerboard metasurface with 10 × 10 elements for RCS reduction. It is inferred from the simulation results that a significant reduction in RCS is observed in the LP-XP band. The dimensions of the realized meta-atom are 0.297 × 0.297 × 0.062 λ03 (where λ0 is dependent on lowest operating frequency), and is best suitable for future wireless communication and RCS reduction application simultaneously. © 2023 IEEE.Item Beam Switchable Compact Retroreflector Based on Dielectric Based Metasurface(Institute of Electrical and Electronics Engineers Inc., 2023) Majumder, B.; Vinnakota, S.S.; Madhusudhan, R.; Kandasamy, K.In this paper a beam switchable compact retro reflector is proposed based on the dielectric based metasurface structure and numerically verified. The core working principal of this device is lying on the principle of half shorted Luneburg lens designed using a dielectric glide symmetric structure in a parallel plate environment which redirects the electromagnetic ray towards the source but along the direction parallel and opposite to the incident direction. The proposed structure operates between 23 GHz and 25 GHz. The proposed antenna scans up-to maximum 60 degree (±30°) in the discrete angular space with a uniform gain and reduced scan loss at all its ports. The simulated gain dip is observed to be less than 2 dBi at a fixed frequency across all of its ports. © 2023 IEEE.Item Broadband Linear to Circular and Multi-Band Cross Polarization Conversion Reflective Metasurface for Ku, K and Ka Band Applications(Institute of Electrical and Electronics Engineers Inc., 2023) Goud, M.; Kandasamy, K.; Majumder, B.This work proposes a low-profile reflective meta-structure to convert incident linearly polarized (LP) waves to circularly polarized (CP) waves with broadband characteristics and also into cross polarized waves with narrowband characteristics. The unit cell in the proposed design consists of a tapered rectangular metal strip along the diagonal and a square patch at the center. When an X-polarized or Y-polarized wave impinges on the meta-structure, it converts into circular polarization in Ku, K and lower portion of spectrum in the Ka-band. This meta-atom exhibits cross polarization conversion from 10.98-12.15 GHz, 31.62-34.26 GHz and 34.95-37.2 GHz. The dimensions of the optimized unit cell are 0.292 × 0.292 × 0.062 λ0·3 mm (where λ0 is calculated based on lowest operating frequency) with axial ratio bandwidth 77.76% can be used for the future wireless communication, also when the actual and mirror meta-atom arranged in checkerboard format can be used for RCS reduction application. © 2023 IEEE.Item A Tunable Frequency Selective Surface for Band Pass and Band Stop Applications(Institute of Electrical and Electronics Engineers Inc., 2024) Goud, M.G.; Paul, P.; Majumder, B.; Kandasamy, K.In this work, a low-profile reconfigurable frequency selective surface capable of dynamically tuning the frequencies for band-pass and band-stop filtering applications is proposed. To realize this, a single-layered FSS is designed with tapered metal strips separated by a central gap and square metal patches positioned at the corners. Two PIN diodes are embedded in both the top and bottom layers. They are positioned at the center of the 45°-oriented metal strips, and for the frequency tuning, at least one of the diodes must be in the ON state. When both the diodes are ON, the tunable metasurface exhibits band-pass characteristics from 8.56- 14.8 GHz and band-stop characteristics from 3.08- 5.2 GHz. Similarly, when the PIN diode is in OFF state, the transmission window is from 6.25-8.1 GHz and band-stop window is from 3.1-4.3 GHz. With these transmission and reflection characteristics, the proposed work is best suitable for wireless and radar applications. © 2024 International Radio Science Union (URSI).Item Active Multifunctional Reflective Metasurface for Linear to Cross and Linear to Circular Polarization Conversion Applications(Institute of Electrical and Electronics Engineers Inc., 2024) Goud, R.M.; Paul, P.; Majumder, B.; Kandasamy, K.A low-profile reconfigurable reflective metasurface capable of dynamically switching polarization conversion functionalities is proposed in this work. To realize this, a single-layered metasurface comprising tapered rectangular metal strips oriented diagonally with a Z-shaped conducting strip in the middle and L-shaped metal strips along the corners is etched on a substrate backed by a conducting layer. A diode is positioned at the center of the diagonally oriented structure, and the switching is controlled using a radial stub-based DC biasing circuit. When the PIN diode is turned OFF, the tunable metasurface reflects cross-polarized waves in the frequency spectrum ranging from 12.3- 15.5 GHz, whereas, in the ON state, it converts linear polarized waves into orthogonally polarized waves from 14.83- 15.83 GHz, also converts linear to left-handed and right-handed circular polarization with an axial ratio of less than 3 dB across four distinct frequency bands. The 45° orientation of the metallic layer makes the structure polarization-independent and can be best used for radar cross-section (RCS) reduction and future wireless and satellite communications simultaneously. © 2024 IEEE.Item Novel Reflective Phased Meta-Atom Array for Beam Forming along Multiple Planes(Institute of Electrical and Electronics Engineers Inc., 2024) Paul, P.; Goud, M.; Kandasamy, K.; Majumder, B.In this paper a novel beam-forming technique for focused microwave power transmission (MPT) at specific frequencies that enables far-field transmission at three directions in the elevation plane is proposed. A simple and planar phased metasurface comprising of an array of subwavelength meta-unit cells is designed to focus the microwave energy at 4.2 GHz at desired angles in the azimuthal and elevation planes. The beam formed is made to focus energy at 0° by a suitably designed meta surface. The phase profile of the meta-atom array is then suitably tuned, to split the RF energy at elevation angles of 70° and -70° directions in azimuthal planes of 45°, 135°,225° and 315°. This ensures the compatibility of the designed reflective array surface with antenna radiators and hence, allows for the availability of power at different directions of focus. This functionality can be used to focus or deflect power in case of sensors placed at different locations in the far-field proximity of the main radiator. A patch antenna radiating at 4.2 GHz is used to conduct the simulation study using CST Microwave Studio. © 2024 IEEE.Item Dual-Functional Reflective-Metastructure Array for Polarization Conversion and Stealth Application(Institute of Electrical and Electronics Engineers Inc., 2024) Madhusudhan Goud, R.; Paul, P.; Kandasamy, K.; Majumder, B.This work proposes a compact, single-layered dualfunctional reflective meta-structure array to convert incident X/Ypolarized EM waves to cross-polarized waves in a portion of Kaband spectrum and to obtain circularly polarized (CP) waves with broadband characteristics in the Ku and K band frequency spectrum. The unit cell comprises of a symmetrical I-shaped metallic resonator with a single rectangular split ring resonator at the centre. The rotation of the induced surface currents on the meta-structure and the phase profile of the reflected waves confirms the presence of left-handed CP waves. When rotated in XY plane around Z-axis by 90°, this meta-atom reflects cross polarized waves with 180° phase difference compared to the original meta-atom across the entire operational bandwidth. This phase profile is utilized to realize a checkerboard metasurface and it is observed that significant RCS reduction is achieved in the cross-polarization conversion band. The overall size of the optimized unit cell is 0.26 × 0.26 × 0.07 λo3 mm3 and reflects CP waves with an axial ratio (AR) less than 3 dB from 15.3 GHz to 26.03 GHz. At the same time, cross-polarization conversion is observed from 28.33 GHz to 35.4 GHz, which makes the design best suitable for future wireless communication and RCS reduction application simultaneously. © 2024 IEEE.Item High Transmissive Beam-Focusing Lenses based on All-dielectric Metasurface(Institute of Electrical and Electronics Engineers Inc., 2025) Goud, R.M.; Paul, P.; Majumder, B.; Kandasamy, K.This paper presents the design and analysis of a fully dielectric transmissive metasurface tailored for beam-focusing applications in the microwave frequency regime, specifically targeting operation at 20 GHz in K-band. The metasurface functions as a high-gain lens, employing flame-retardant resin to construct meta-atoms composed of cylindrical dielectric structures positioned on a dielectric substrate. By modulating the height of these cylinders, a continuous phase gradient ranging from 0° to 360° is achieved, enabling precise wavefront control for focusing incident electromagnetic waves along the broadside direction. Each meta-atom is optimized to maintain a transmittance greater than 90%, ensuring minimal energy loss during transmission. The required phase distribution across the metasurface is initially derived using MATLAB-based numerical synthesis, followed by full-wave parametric simulations in CST Studio Suite to correlate the geometrical variations with the desired phase shifts. Unlike conventional designs that rely on metallic inclusions or ground planes, this work introduces a novel all-dielectric architecture, offering advantages in cost-effective 3D printing fabrication, reduced weight, and enhanced efficiency. The 1D and 3D radiation patterns confirm the beam-focusing behavior of the metasurface, demonstrating its potential for integration into compact, high-performance lens-based systems for advanced wireless communication and radar applications. © 2025 IEEE.Item A Zero Index Based Meta-Lens Loaded Wideband Directive Antenna Combined with Reactive Impedance Surface(Institute of Electrical and Electronics Engineers Inc., 2018) Majumder, B.; Kandasamy, K.; Ray, K.P.In this paper, an aperture efficient wideband high-gain patch antenna is designed using a novel multilayer-based metamaterial structure combined with a reactive impedance surface (RIS)-backed patch antenna. The metamaterial unit cell is a two-layer structure which is stacked one after other to form the overall unit cell. The microscopic behavior of the proposed unit cell has been investigated. This unit cell gives low refractive index over a wide bandwidth with a negligible loss. An RIS-backed patch antenna has been designed in the required frequency band to feed the multilayer zero-index metamaterial medium. The introduction of this surface is to provide unidirectional radiation over a wideband in the zero refractive index region. The proposed antenna gives a 14% fractional bandwidth over the $C$ - and $X$ -bands. The proposed antenna enhances the peak gain of the conventional patch antenna by an amount of 8.5 dB at 8 GHz. Finally, the antenna has been fabricated and its performance is verified experimentally. © 2013 IEEE.