Journal Articles
Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/19884
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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.Item Dispersion-Engineered Transmission Line Loaded Slot Antenna for UWB Applications(Institute of Electrical and Electronics Engineers Inc., 2019) Paul, P.M.; Kandasamy, K.; Sharawi, M.S.; Majumder, B.A transmission line (TL) loaded, compact, ultrawideband (UWB) square slot antenna is proposed in this letter. The square slot is a microstrip line fed and loaded with an array of periodically perturbed TLs to achieve a UWB response from 2.1 to 11.5 GHz. The slot is designed to resonate at 2.6 GHz. The TLs are dispersion engineered to resonate at several frequencies so as to provide a wideband response. Loading of the engineered TLs on the square slot produced multiple resonances without affecting the fundamental mode of the slot antenna. The proposed antenna design is analyzed using dispersion relations and equivalent circuits. The proposed antenna is fabricated on an RT/Duroid 5880 substrate with a size of 50 × 50 × 1.52 mm3. The antenna performance metrics, such as impedance bandwidth, gain, and efficiency, are experimentally verified. Good agreement is obtained between simulated and measured results. © 2018 IEEE.Item Goubau line based end-fire antenna(John Wiley and Sons Inc. P.O.Box 18667 Newark NJ 07191-8667, 2019) Rudramuni, K.; Tharehalli Rajanna, P.K.T.; Kandaswamy, K.; Majumder, B.; Zhang, Q.This article proposes a simple and low profile planar Goubau line based end-fire antenna. End-fire radiation is achieved by modifying the Goubau line into inverted periodic arrangement of V-shaped unit cells. Designed prototype is simulated and verified experimentally. Both the simulated and measured results are in good agreement. Proposed antenna radiates toward end-fire direction between 7.8 and 8.3 GHz. The maximum gain of the antenna is obtained around 7.2 dBi. The average efficiency is observed 70% over the entire operating bandwidth. Proposed end-fire antenna has a single metallic layer with simple configuration which is easy to fabricate and also easy to integrate with other electronics circuits. The proposed antenna can be used for satellite and RADAR applications. © 2019 Wiley Periodicals, Inc.Item Dual-band dual-polarized leaky-wave structure with forward and backward beam scanning for circular polarization-flexible antenna application(John Wiley and Sons Inc. P.O.Box 18667 Newark NJ 07191-8667, 2020) Rudramuni, K.; Majumder, B.; Kandasamy, K.In this paper, a novel dual-band dual-polarized leaky-wave antenna (LWA) with polarization diversity is proposed using half mode substrate-integrated waveguide (HMSIW)-based technology. HMSIW LWAs are generally single band. In this work, by etching simple spiral type slots on the HMSIW cavity, a novel dual-band dual-polarized LWA is designed. The proposed antenna resonates at 5.6 and 8.5 GHz. Moreover, the antenna radiates the linearly polarized wave in the lower band and circularly polarized (CP) wave in the higher operating band. Also, in the higher operating band between 8.7 and 9.3 GHz, the proposed overall antenna exhibits both right-hand circular polarization as well as the left-hand circular polarization in the near main beam direction. The ?10 dB impedance bandwidth of the proposed antenna at the lower and the higher operating bands are 27% (4.86-6.4 GHz) and 25% (7.4-9.6 GHz), respectively. In the higher band, the 3-dB axial ratio bandwidth of 6.6% (8.7-9.3 GHz) is achieved. The main beam of the antenna can be steered from 19° to 69° in the forward direction in the lower operating band. In the higher operating band, the antenna can steer the CP beam between ?17° and ?32°. In both the lower bands, the realized peak gain is observed around 13.3 dBi, whereas in the higher band, the realized peak gain is observed around 14 dBi. © 2020 Wiley Periodicals, Inc.Item Dual-Band Asymmetric Leaky-Wave Antennas for Circular Polarization and Simultaneous Dual Beam Scanning(Institute of Electrical and Electronics Engineers Inc., 2021) Rudramuni, R.; Majumder, B.; Tharehalli Rajanna, T.R.; Kandasamy, K.; Zhang, Q.In this article, two configurations of novel dual-band half-mode substrate integrated waveguide (HMSIW) leaky-wave antennas are presented. The first proposed antenna radiates linearly polarized (LP) waves in the lower band and circularly polarized waves in the upper band when the unit cells are cascaded sequentially. The second antenna, where the sidewall via of the HMSIW unit cells is connected alternatingly, provides simultaneous dual beams with different polarization in the upper operational band in addition to the LP beam in the lower operational band. The unit cells of the two antennas are analyzed in terms of their dispersion behaviors. Finally, the performance of both the antennas is experimentally verified. © 1963-2012 IEEE.Item Dielectric Metasurface Inspired Directional Multi-Port Luneburg Lens as a Medium for 5G Wireless Power Transfer - A Design Methodology(Institute of Electrical and Electronics Engineers Inc., 2022) Majumder, B.; Vinnakota, S.S.; Upadhyay, S.; Kandasamy, K.In this paper, a novel dielectric metasurface-inspired multi-beam directional Luneburg lens is proposed as a wireless power transfer medium at 5G mm-wave band. The lens is constructed using dielectric-based unit cells made up of a glide symmetric approach. It is connected with a set of microwave detector integrated multi-port tapered rectangular feeds to convert the received RF energy from different directions to DC power across a combined load. The proposed structure can be a potential candidate to harvest ambient energy from a wide coverage range of around 160° and produce a power conversion efficiency of about 76% for an input power of 14.9 dBm at 24 GHz. © 2009-2012 IEEE.Item Dual Frequency Multi-Functional via-Less Leaky Wave Antenna Featuring Enhanced Frequency Sensitivity and Dual Beam Scanning Capability(Institute of Electrical and Electronics Engineers Inc., 2024) Majumder, B.; Vinnakota, S.S.; Goud Rangula, M.; Kandasamy, K.In this paper we present a dual band low cross-polarized periodic microstrip leaky wave antenna (LWA) based on the multi mode resonator concept (MMR). The structure is capable of frequency dependent backward dual-beam steering and fast forward beam scanning in the upper and lower operating band, respectively. A gap loaded microstrip line is used as a host transmission line to feed the combination of the periodic patch radiators on the top and the bottom etched slots leading to the generation of the forward and the backward space harmonics. The etched ring slots at the bottom surface of the structure are not only responsible for steering the beam in the backward direction in the bottom hemisphere in its upper band but also adds radiation diversity in the overall radiation mechanism in its two operating bands. The potential use of this antenna resides in its ability to produce in-plane fast forward beam steering suitable for autonomous vehicle navigation systems in its lower band and out-of-plane backward-symmetric dual beam steering in the upper operating bands, suitable for tracking in relay systems. © 2013 IEEE.Item An ultra-broadband low profile modified chessboard metasurface with improved backscattering reduction(Elsevier B.V., 2025) Goud, M.G.; Paul, P.; Majumder, B.; Kandasamy, K.Building upon the concepts of polarization conversion and the mechanism of destructive interference, a single-layered ultra-broadband metasurface for radar cross-section (RCS) or backscattering reduction is proposed in this work. A diffusion-assisted checkerboard metasurface with re-tailored unit cells at the center leads to a significant improvement in the stealth characteristics. For this, a low profile and less complex unit cell is proposed, comprising a long metallic strip along the diagonal and two thin horizontal stubs at the edges. This unique arrangement exhibits more than 90% polarization conversion efficiency from 13.2 to 38.2 GHz. Modifying the geometry of central elements in a conventional checkerboard metasurface achieves a minimum of 15 dB RCS reduction from 10 to 38 GHz. Also, as we ascend the frequency spectrum, the beams are scattered in unintended directions with reduced signal strength. Notably, there is no beam in the boresight direction, as opposed to the conventional chessboard configurations. For off-normal incidences, the metasurface exhibits good angular stability, and a minimum of 10 dB backscattering reduction is maintained up to an incidence angle variation of 60°. The final optimized fabricated prototype exhibits measurement results that agree with the simulation results for normal and wide-angle incidences. © 2024 Elsevier B.V.Item An ultra-broadband polarization conversion metasurface for enhanced stealth and RCS mitigation in MIMO configurations(Elsevier GmbH, 2025) Goud, M.G.; Paul, P.; Majumder, B.; Kandasamy, K.A single-layer broadband metasurface for efficient cross-polarization conversion, aiming at improving the stealth performance of a MIMO antenna, is proposed in this work. A low-profile, minimally complex meta-atom and its mirror image are proposed, featuring a diagonal metallic strip and two narrow horizontal edge strips. This configuration achieves more than 90 % polarization conversion efficiency while maintaining an absolute 180-degree phase gradient between the reflected waves of the two meta-atoms. A chessboard metasurface with 10x10 elements, constructed with the proposed meta-atom and mirror image, is integrated with the slot antenna-based MIMO configuration. A slot antenna is orthogonally arranged to form a four-element MIMO configuration, ensuring high isolation exceeding 25 dB between the individual elements. The realized peak gain of this arrangement is 6.95 dBi radiating orthogonally. Monostatic, bistatic, and 3D scattering patterns of a MIMO configuration with and without metasurface are evaluated. Under oblique incidence, the metasurface demonstrates exceptional angular stability, maintaining a minimum RCS reduction of 10 dB for incidence angles up to 60°. The fabricated and optimized prototype exhibits measurement outcomes that closely correspond to the simulation results for normal and oblique incidence scenarios. © 2025 Elsevier GmbH