Faculty Publications
Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736
Publications by NITK Faculty
Browse
11 results
Search Results
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 A triband circularly polarized strip and SRR-loaded slot antenna(Institute of Electrical and Electronics Engineers Inc., 2018) Paul, P.M.; Kandasamy, K.; Sharawi, M.S.In this communication, a simple and compact multiband circularly polarized (CP) slot antenna loaded with metallic strips and a split-ring resonator (SRR) is proposed. The multiband operation is obtained via exciting the SRR and copper strips by the microstrip-fed square slot antenna. The SRR resonates at 1.83 GHz, while the strips and the slot antenna provide resonances at 2.5 and 3.1 GHz. Resonant modes of loaded SRR and strips combined with the fundamental mode of the slot produce CP waves at the resonance frequencies of the proposed antenna. The proposed antenna allows for independent tuning of different bands via the use of the tilted strips and the SRR. Also, the sense of polarization at the resonance frequencies can be controlled by changing the orientation of the strips and the SRR with respect to the slot. The proposed antenna is fabricated on an FR-4 substrate of dimension 50 × 50 × 1.56 mm3. Antenna performances in terms of 10 dB return loss bandwidth, 3 dB axial ratio bandwidth, gain, and efficiency are validated experimentally and are in a good agreement with the simulated results. © 2018 IEEE.Item A High-Gain Circularly Polarized Antenna Using Zero-Index Metamaterial(Institute of Electrical and Electronics Engineers Inc., 2019) Tharehalli Rajanna, P.K.T.; Rudramuni, K.; Kandasamy, K.In this letter, a novel high-gain circularly polarized (CP) antenna based on the zero-index metamaterial (ZIM) is presented. A square ring with two asymmetrical splits is used as a unit cell to achieve high gain and circular polarization. The 9 × 9 periodic array unit cells act as an aperture efficient focusing metasurface lens and polarization converter for a primary source antenna. The focusing effect of the ZIM enhances the gain of the microstrip patch antenna placed above it by an amount of 5-6 dB. Also, the ZIM converts the linearly polarized wave emitted by the patch antenna into circularly polarized waves. The circular polarization is achieved by optimizing the two split gaps on the ring of the unit cell, which gives two orthogonal polarizations with the required phase. The proposed design is fabricated and verified experimentally. The prototype has measured impedance bandwidth from 7.04 to 7.68 GHz. The 3 dB axial ratio is achieved from 7.11 to 7.56 GHz, with a peak gain of 12.31 dBic at 7.45 GHz. The gain of around 11.5 dBic is achieved over the entire CP bandwidth with a good cross-polarization level. © 2002-2011 IEEE.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 Mitigation of mutual coupling in 2 X 2 dual slant polarized MIMO antennas using periodic array of SRRs loaded with transmission line for LTE band 40(John Wiley and Sons Inc, 2020) Bellary, A.; Kandasamy, K.; Rao, P.H.2 X 2 dual slant polarized multiple input multiple output (MIMO) antennas with reduced mutual coupling is presented for polarization and spatial diversity. The design of printed periodic array of split ring resonators (SRRs) loaded with horizontal strip transmission line is proposed to mitigate the mutual coupling among the MIMO antenna elements. An equivalent circuit model, characterizes the effect of coupling between the array of SRRs and the loaded transmission line, which together reduces the near field coupling between the adjacent antenna elements. The additional horizontal strip at the bottom is utilized to seek the return current path to the ground plane. Polarization and spatial diversity is achieved by utilizing dual slant 450 polarized antenna elements with eight independent channels. All four dual polarized antenna elements are designed to operate with a VSWR of <2 for (2.3-2.4 GHz) Band 40. Dual slant 450 polarization is achieved by utilizing two printed planar bow-tie antennas in orthogonal orientation. Measured and simulated results shows by incorporating periodic array of SRRs loaded with transmission line a considerable mutual coupling reduction of 25 to 50 dB is achieved in E-plane, H-plane, and D-plane over the required band 40. An isolation of 30 dB and an average gain of 7.5 dB is measured for dual slant 450 polarized antenna elements. MIMO performance metrics in terms of envelope correlation coefficient and diversity gain are also investigated. © 2020 Wiley Periodicals LLCItem Analysis of Wave Propagation Models with Radio Network Planning Using Dual Polarized MIMO Antenna for 5G Base Station Applications(Institute of Electrical and Electronics Engineers Inc., 2022) Bellary, A.; Kandasamy, K.; Rao, P.H.Dual polarized printed multiple input multiple output (MIMO) antenna for Band 42 (3.4 - 3.6 GHz) with wave propagation models is presented. Polarization and spatial diversity are achieved by utilizing two printed bow-tie antennas in orthogonal orientation. The designed dual polarized antenna element with $2\times 2$ , $4\times 4$ and $8\times 8$ massive MIMO antenna configuration radiation patterns are deployed in selected geographical situation for detailed radio network planning using FEKO-WinProp platform. Knife edge diffraction, extended walfisch-ikegami and dominant path wave propagation models are implemented with designed MIMO antenna configurations. Modulation schemes of QPSK and QAM with corresponding data rates and throughput for all propagation models are presented. The signal strength and quality reflecting parameters reference signal received power (RSRP), received signal strength indicator (RSSI), reference signal received quality (RSRQ), and signal to noise plus interference ratio (SNIR) are also evaluated for each model. From the simulation results dominant path model provides data rate and throughput of 3.827, 995 MBit/s and 3.577, 930.1 MBit/s for single stream of data in uplink and downlink respectively. The maximum data rate of 1.37 GBits/s is achieved for deployed base stations with $8\times 8$ massive MIMO antenna configuration effectively covering the entire geographical site. © 2013 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 A Novel Single-Layered Dual-Wideband Circularly Polarized Asymmetric Slot Antenna for Wireless Applications(Electromagnetics Academy, 2024) Shankaraiah, P.H.; Shet, N.S.V.; Kandasamy, K.This work focuses on the design and implementation of a dual-wideband asymmetric square-shaped slot radiator with coplanar waveguide (CPW) feed for circular polarization (CP) characteristics. The proposed radiator has inward ground plane extensions in the form of square and rectangular strips on the diagonal corners of the slot. By optimizing the size of strips, a dual-band antenna with CP behaviour is obtained. The inverted L-shaped grounded strip improves axial ratio bandwidth (ARBW). The extended signal line terminated in a wide tuning stub significantly improves impedance bandwidth (IBW) and also further enhances ARBW. The designed asymmetric slot radiator is fabricated using an FR-4 substrate material of dimensions 50×50×1.6 mm3. This antenna design gives flexibility to alter polarization sense at the dual frequency bands. Further, edge effects are analyzed through electric field distribution, and their impact on impedance and AR characteristics are studied. It is designed, fabricated, and tested, and shows right-hand circular polarization (RHCP) response at 3 GHz and 7.5 GHz in the +Z direction. The experimentally verified results show −10-dB IBWs of 40.12% (range from 2.61 GHz to 3.92 GHz) and 40.21% (range from 6 GHz to 9.02 GHz), and 3-dB ARBWs are 20% (range from 2.70 GHz to 3.30 GHz) and 40.21% (range from 6 GHz to 9.02 GHz) at the resonance bands. The experimentally measured and simulated performance parameters of the prototype are in close agreement. The proposed perturbed slot radiator is well suited for Wi-Fi 6E communication and remote sensing applications. © 2024, Electromagnetics Academy. All rights reserved.Item Graphene Oxide Assisted Humidity Sensing Antenna Sensor(Korean Institute of Electrical and Electronic Material Engineers, 2025) Singh, V.P.; Kandasamy, K.; Rahman, M.R.Abstract: In this paper, a graphene oxide (GO) coated substrate material is electrically characterized. The permittivity, loss tangent, permeability, and resistance are measured. A planar antenna with slots is designed on an RT/Duroid 5880 substrate. A thin layer of graphene oxide is coated on the identical slots of the planar antenna. The GO-assisted antenna sensor resonates at 2.51 GHz frequency. The graphene oxide-based antenna sensor performs contact-free sensing of relative humidity. The frequency sensitivity is approximately 17.5 MHz/10%RH. The design sensor gives a 93.50% linearity. The limit of detection is 30.55 RH%. Graphic Abstract: (Figure presented.) © The Korean Institute of Electrical and Electronic Material Engineers 2024.Item Metamaterial based stepped microstrip line fed quad-band dual-sense circularly polarized slot antenna for wireless applications(Cambridge University Press, 2025) Shankaraiah, P.H.; Shet, N.S.V.; Kandasamy, K.This research proposes a low-complexity, low-profile square-shaped quad-band dual-sense circularly polarized (CP) perturbed slot antenna with stepped microstrip feed for C-band radar and satellite applications. The proposed antenna is characterized by characteristic mode analysis. The proposed design has a square-shaped slot with diagonally opposite symmetric rectangular corner extensions. Multiband resonance is achieved by exciting the split ring resonator (SRR), cross strips and annular ring structure using the stepped microstrip line-fed slot radiator. The slot antenna and a metallic ring resonate at 1.64 and 8.2 GHz, respectively, showing left-hand circular polarization response, whereas the SRR and cross strips resonate at 3.6 and 6.6 GHz, respectively, exhibiting right-hand circular polarization radiation at these resonance bands. Hence, the proposed design shows quad-band performance with dual-sense CP behavior. Furthermore, the proposed antenna allows for independent tuning of polarization sense at resonance frequencies. The proposed design uses a low-cost FR-4 material as a substrate of dimensions 60 × 60 × 1.6 mm3. The experimentally measured results are in close agreement with the simulated performance parameters of the prototype. © The Author(s), 2025. Published by Cambridge University Press in association with The European Microwave Association.