Journal Articles
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Item A tri-band slot antenna loaded with split ring resonators(John Wiley and Sons Inc. P.O.Box 18667 Newark NJ 07191-8667, 2017) Paul, P.M.; Kandasamy, K.; Sharawi, M.S.A compact tri-band slot antenna with independent tuning capability of its resonant frequencies is proposed in this article. A microstrip line fed square slot is loaded with split ring resonators (SRR) to obtain multiband characteristics. The slot is designed to resonate at 2.6 GHz. Two SRRs with single and multiple splits are loaded with the slot, which provide additional resonances at 4.3 and 4.7 GHz, respectively. Parametric analysis of the antenna shows that its resonance frequencies are controlled independently. The proposed antenna is fabricated on an FR4 substrate with a size of 60 × 60 × 1.56 mm2. The proposed design offers stable omnidirectional patterns and >3.8 dBi at all the resonating frequency bands. © 2017 Wiley Periodicals, Inc.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 Goubau-Line Leaky-Wave Antenna for Wide-Angle Beam Scanning from Backfire to Endfire(Institute of Electrical and Electronics Engineers Inc., 2018) Rudramuni, R.; Kandasamy, K.; Zhang, Q.; Tang, X.-L.; Kandwal, A.; Tharehalli Rajanna, T.R.; Liu, H.A Goubau-line leaky-wave antenna (LWA) with a large scanning angle is presented in this letter. In contrast to the conventional Goubau-line leaky wave with a small scanning angle range, this letter employed a periodically bending Goubau line, which not only brings in a periodic perturbation for leaky-wave radiation, but also enhances the scanning range due to the increased delay for each line element. The simulation and experimental results show that the proposed LWA provides 90 radiation efficiency and 7-10 dBi radiation gain from backfire to endfire through broadside as frequency changes. The proposed antenna features good radiation performance and has a compact and low-profile configuration. © 2011 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 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 Wideband Circularly Polarized Slot Antenna Backed by a Frequency Selective Surface(Korean Institute of Electromagnetic Engineering and Science, 2019) Kumar, P.; Tharehalli Rajanna, P.K.T.; Rudramuni, K.; Kandasamy, K.This paper presents the design of a coplanar waveguide (CPW)-fed single-layer wideband circularly polarized (CP) planar slot antenna backed by a frequency selective surface (FSS). The planar slot antenna is fed with a stub-loaded modified CPW feed line to tune and optimize the impedance bandwidth. The corners of the square slot antenna are perturbed to produce two orthogonal degenerate modes required for a wideband CP operation. The FSS layer is placed under the slot antenna to increase the gain and axial ratio bandwidth. The measured results of the proposed antenna provide an impedance bandwidth of 63.22% and an axial ratio bandwidth of 31.14% with a peak gain of 4.87 dB. The proposed antenna has a simple geometry, a wide CP bandwidth, and a good gain. © 2019. The Korean Institute of Electromagnetic Engineering and Science. All Rights Reserved.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 Compact Wideband Circularly Polarized SRR Loaded Slot Antenna for Soil Moisture Sensor Application(Society for Microwave Technique, Technologies and System, 2020) Tharehalli Rajanna, P.K.; Rudramuni, K.; Kandasamy, K.– This paper presents a coplanar waveguide (CPW) fed corner truncated square slot antenna loaded with a split ring resonator (SRR) for soil moisture sensor application. The truncated corner square slot produces a circularly polarized wave with two orthogonal degenerate modes at 4.12 GHz with 3-dB axial ratio bandwidth of 17.69%. Further, the axial ratio bandwidth is increased to 21.81% by loading a rotated SRR on the slot. The split gap of the inner ring of SRR is rotated 90° with respect to outer ring gives circular polarization (CP) at 4.62 GHz. The wideband CP performance is achieved by the combination of truncated corner slot and rotated SRR mode resonances. Both bands are tuned independently to optimize the wide axial ratio bandwidth. The designed antenna is fabricated, and its performance is verified experimentally. The measured impedance bandwidth of 2.53 GHz (61.40%) and axial ratio bandwidth of 0.9 GHz (21.68%) with a peak gain of 2.74 dB is observed. The proposed wideband CP antenna is utilized for soil moisture sensing application and high sensitive microwave sensing application. © 2020