Faculty Publications
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Publications by NITK Faculty
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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 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 Compact triband circularly polarized planar slot antenna loaded with split ring resonators(John Wiley and Sons Inc. P.O.Box 18667 Newark NJ 07191-8667, 2019) Tharehalli Rajanna, P.K.T.; Rudramuni, K.; Kandasamy, K.In this article, a coplanar waveguide (CPW) fed triband circularly polarized (CP) planar slot antenna loaded with split ring resonators (SRRs) is presented. The truncated slot antenna resonates at 4.15 GHz, which gives two orthogonal degenerate modes to produce circular polarization at the first band. The second and third band resonances are achieved at 4.77 GHz and 5.1 GHz respectively due to the loading of SRRs on the slot antenna. The electric fields produced by the single and multiple split gaps in each ring of SRR1 and SRR2 produce CP at the second and third band. All three bands are tuned independently to achieve optimized axial ratio bandwidth. The antenna is fabricated and verified experimentally. The measured results give impedance bandwidth of 64.54% and axial ratio bandwidths of 11.76%, 1.9%, and 3.87% at first, second, and third band, respectively. © 2019 Wiley Periodicals, Inc.Item A corner expanded slot antenna loaded with copper strips for dual-band circular polarization characteristics(John Wiley and Sons Inc. P.O.Box 18667 Newark NJ 07191-8667, 2020) Paul, P.M.; Kandasamy, K.; Sharawi, M.S.In this article, the design and implementation of a dual-band circularly polarized (CP) microstrip line fed square slot antenna with compact size is proposed. The proposed CP antenna consists of a square slot antenna with a pair of symmetric rectangular extensions on opposite corners and loaded with an array of inclined and truncated rectangular copper strips. The square slot with diagonal extensions resonates at 2.24 to 2.62 GHz with a 3 dB axial ratio (AR) bandwidth of 15.7%. Besides, loading it with an array of inclined and truncated rectangular copper strips helps produce a resonance at higher band with CP. The higher band operates between 3.26 and 5.18 GHz and centered at 4.52 GHz, with a 3 dB AR bandwidth of 45.5%. The polarization sense and resonant frequency of the proposed antenna can be independently tuned depending on the position and dimensions of the slot and strips, respectively. The proposed antenna is fabricated and measured in terms of impedance bandwidth, axial ratio bandwidth, peak gain, and radiation efficiency. Good agreement between the simulations and measurements of the prototype is obtained. © 2019 Wiley Periodicals, Inc.Item Characteristic mode-based compact circularly polarized metasurface antenna for in-band RCS reduction(Cambridge University Press Journals_subscriptions@cup.cam.ac.uk, 2020) Tharehalli Rajanna, P.K.; Rudramuni, K.; Kandasamy, K.This paper presents a novel design of a low profile circularly polarized (CP) metasurface (MTS) antenna with in-band radar cross-section (RCS) reduction property. The MTS is loaded as a superstrate on slot antenna and it can be viewed as a polarization-dependent MTS (PDMTS). The rectangular patch-based PDMTS is analyzed using characteristic mode analysis to find two orthogonal degenerate modes, which produces CP waves. Linearly polarized slot antenna is used to excite the PDMTS. The performance of PDMTS loaded slot antenna is analyzed numerically using full-wave analysis method. The PDMTS CP antenna is fabricated and its performance is tested experimentally. The proposed antenna has a compact structure and it has an overall size of (where is the free space wavelength). The measured results show that the PDMTS antenna achieves impedance bandwidth of 29.41, 3-dB axial ratio bandwidth of 9.05, broadside gain of 6.34 dB, and monostatic RCS reduction of at the resonant frequency of 5.86 GHz. The simulated results are in well agreement with the measured results and it is well suited for C-band Radar and Satellite communication. © © Cambridge University Press and the European Microwave Association 2019.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 Compact uwb slotted monopole antenna with diplexer for simultaneous microwave energy harvesting and data communication applications(Electromagnetics Academy, 2021) Polaiah, G.; Kandasamy, K.; Kulkarni, M.This paper proposes a new integration of compact ultra-wideband (UWB) slotted monopole antenna with a diplexer and rectifier for simultaneous energy harvesting and data communication applications. The antenna is composed of four symmetrical circularly slotted patches, a feed line, and a ground plane. A slotline open loop resonator based diplexer is implemented to separate the required signal from the antenna without extra matching circuit. A microwave rectifier based on the voltage doubler topology is designed for RF energy harvesting. The prototypes of the proposed antenna, diplexer, and rectifier are fabricated, measured, and compared with the simulation results. The measurement results show that the fractional impedance bandwidth of proposed UWB antenna reaches 149.7% (2.1 GHz–14.6 GHz); the diplexer minimum insertion losses (|S21 |, |S31 |) are 1.37 dB and 1.42 dB at passband frequencies; the output isolation (|S23 |) is better than 30 dB from 1 GHz to 5 GHz; and the peak RF-DC conversion efficiency of the rectifier is 32.8% at an input power of ?5dBm. The overall performance of the antenna with a diplexer and rectifier is also studied, and it is found that the proposed new configuration is suitable for simultaneous microwave energy harvesting and data communication applications. © 2021, Electromagnetics Academy. All rights reserved.Item Circularly polarized rectangular dielectric resonator antenna with elliptical aperture feed for 5 GHz ISM band(John Wiley and Sons Inc, 2021) Usha, L.; Kandasamy, K.In this article, a new elliptical slot aperture feed circularly polarized (CP) rectangular dielectric resonator antenna (RDRA) has been proposed. The nonresonant slot excites two spatially orthogonal resonant frequencies in RDRA to produce CP waves. TEx111 and TEy111 are the orthogonal modes produced by the 450 inclined elliptical slot with respect to microstrip feed. Also, the sense of polarization at the resonance frequencies can be controlled by changing the orientation of the slot. The antenna performances in terms of impedance bandwidth, 3-dB axial ratio, and gain are validated experimentally. The proposed antenna can be used in 5 GHz ISM band for WiFi/satellite communications. © 2021 Wiley Periodicals LLC.Item Circularly polarized rectangular dielectric resonator antenna with metallic strips load for WLAN application(John Wiley and Sons Inc, 2022) Usha, L.; Kandasamy, K.This article presents a circularly polarized rectangular dielectric resonator antenna (CP RDRA) loaded with metallic strips. The dielectric resonator (DR) with metallic strips on the top surface is excited by a slot aperture feed that excites two orthogonal modes to provide circular polarization. The proposed CP RDRA does not require any complex-shaped dielectric resonator and simplifies the overall design. A prototype of the proposed antenna has been fabricated and validated. It has measured impedance bandwidth between 4.8 and 5.6 GHz and 3 dB axial ratio bandwidth between 5.1 and 5.43 GHz. The axial ratio beamwidth of more than 155° in the XZ and YZ planes is obtained. © 2022 Wiley Periodicals LLC.