Faculty Publications
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Publications by NITK Faculty
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Item Dual Band-Dual Sense Circularly Polarized Patch Antenna for Wi-Max Application(Institute of Electrical and Electronics Engineers Inc., 2018) Bande, V.; Tharehalli Rajanna, T.R.; Kandasamy, K.A rectangular slotted patch antenna with circular rings as parasitic element for accomplishing dual-band dual-sense circular polarization (CP) for wireless application is presented in this paper. The proposed antenna is of compact size having dimension of 31x21x1.575mm3. The dual band is achieved by square patch with multiple slots along with Circular ring like structure on backside. The given antenna consist of two resonating frequency band 4.25 GHz and 5 GHz , while considering return loss as S11<-10dB and the 3-dB axial ratio (AR) bandwidth of 1.8% (from 4.18 to 4.257 GHz) and 2.8% (from 4.94 to 5.08 GHz) in lower and upper bands, respectively. The proposed antenna is fabricated and tested experimentally. The measured and simulation results are in agreement. © 2018 IEEE.Item Dual Band Circularly Polarized Slot Antenna Loaded with Asymmetric Cross Strips(Institute of Electrical and Electronics Engineers Inc., 2018) Tharehalli Rajanna, T.R.; Rudramuni, R.; Kandasamy, K.In this paper, a dual band circularly polarized (CP) slot antenna loaded with asymmetric cross strips is proposed. It consists of a corner perturbed slot and two asymmetric strips oriented diagonally with the slot. The slot antenna is excited by 50\Omega microstrip line. The proposed antenna resonates at 2.7 GHz and 3.2 GHz. Two orthogonal degenerate modes produced by the perturbed slot antenna gives CP in lower band and the combination of slot and strip mode gives CP in upper band. The proposed antenna is fabricated and experimentally verified with axial ratio (AR) bandwidth of 13.27% and 13.31% in lower and upper band respectively. The peak gain of 4.68 dB at lower band and 4.81 dB at upper band is achieved. The simulated and measured results are in well agreement and it is good candidate for WiMax and WLAN applications. © 2018 IEEE.Item A Zero-Index Based Metasurface Antenna with Improved Gain and Circular Polarization Characteristics(Institute of Electrical and Electronics Engineers Inc., 2021) Tharehalli Rajanna, T.R.; Rudramuni, R.; Kandasamy, K.A zero-index based metasurface (MTS) is used to increase the gain of a circularly polarized (CP) patch antenna. The patch antenna is truncated at its corner to obtain the CP wave. The patch antenna gain in increased by loading the metasurface. The proposed CP antenna with enhanced gain is fabricated and verified experimentally. A measured impedance bandwidth (< -10dB) of 530 MHz and axial ratio bandwidth (< 3dB) of 100 MHz is achieved. The peak gain of 12.15 dBiC is obtained at the center frequency of 7.47 GHz with a better level of cross-polarization. © 2021 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 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 Flexible Electromagnetic Shielding Material Using Multi-Walled Carbon Nanotube Coated Cotton Fabric(Institute of Electrical and Electronics Engineers Inc., 2022) Arun Kumar, D.S.; Tharehalli Rajanna, T.R.; Kandasamy, K.; Bhat Panemangalore, P.; Rahman, M.R.The present work focuses on the development of cotton fabric with multi-walled carbon nanotube coating (CMC) through a dip and dry process. The influence of multi-walled carbon nanotubes (MWCNTs) concentration on transmission, reflection, and absorption properties, which leads to an estimation of electromagnetic interference (EMI) shielding, was also studied. The merits of MWCNTs coating on the cotton fabric were evaluated using field-emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), and surface resistivity. The Fourier transform infrared (FTIR) spectroscopy result supports the bonding between MWCNTs and cotton fabric. The significant increase of 98.9% of EMI shielding for the highest MWCNTs weight percentage (22.23 wt%) was attributed due to the well-interconnected network of MWCNTs. The shielding mechanism in the high wt% MWCNTs samples is dominated by both reflection and absorption properties. © 2011-2012 IEEE.