Faculty Publications
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Publications by NITK Faculty
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Item Radiations from double notched square patch antenna on FR4 substrate(2008) Bhardwaj, D.; Bhatnagar, D.; Sancheti, S.; Soni, B.This paper presents the radiation performance of a square patch antenna having two triangular notches on opposite edges designed on glass epoxy FR4 substrate and its performance is compared with a simple square patch antenna without any notch. The simulated results for this antenna are obtained by varying notch angle and compared with the measured results. The results indicate that square patch antenna with both notch angles equal to 168o resonates not only at two different frequencies but also offers a much higher bandwidth in comparison to a normal square patch (without notches). Both these resonance frequencies lie in the median band (3.25 to 3.85 GHz) allotted by IEEE 802.16 working group for WiMAX systems. The performance of antenna is optimized considering different conditions to obtain an antenna with dual band and high bandwidth performance. The radiation patterns, gain and radiation efficiency of antenna are also determined. © 2008 SBMO/SBMag.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 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 Slot coupled dual band high gain circularly polarized metasurface antenna(John Wiley and Sons Inc, 2022) Tharehalli Rajanna, P.K.; Rudramuni, K.; Kandasamy, K.This article presents a slot coupled dual-band metasurface (MTS) based antenna with high gain and circular polarization characteristics. The MTS consists of two different unit cells, which give rise to two operating bands. The metasurface is excited by the slot aperture fed by a 50 Ω microstrip feed-line. The circular polarization is achieved by the diagonally oriented rectangular patch-based unit cells on top of the square substrate. Two orthogonal modes of MTS are required to produce circularly polarized waves, and these modes are excited by the slot aperture. The proposed MTS-inspired antenna is fabricated and experimentally validated. The experimentally verified impedance bandwidth of 33.71% in the lower frequency band and 5.35% in the upper-frequency band is achieved. The measured 3 dB (AR <3 dB)axial ratio bandwidth of 6.22% and 0.98% with a peak gain of 8.89 and 6.32 dBic is achieved with respect to 4.8 and 6.4 GHz resonant frequencies. © 2022 Wiley Periodicals LLC.Item A 0.15 μm GaN HEMT device to circuit approach towards dual-band ultra-low noise amplifier using defected ground bias technique(Elsevier GmbH, 2023) Gupta, M.P.; Kumar, S.; Elizabeth Caroline, B.; Song, H.; Kumar, V.; Gorre, P.This work presents a GaN HEMT device to circuit approach towards low noise amplifier (LNA) using defective ground bias (DGB) technique. This is the first MMIC GaN HEMT LNA design to offer dual-band of operation in both L and S-bands to the author's best knowledge. The proposed 0.15-μm GaN HEMT device fabrication achieves a high output power of 20 W using slot radiation phenomenon. The proposed DGB technique consists of gate and drain biasing topologies which achieves a dual-band of operation using microwave approach. The DGB technique is incorporated into GaN HEMT LNA which achieves high input and output power with good stability. To achieve an optimal noise, high I/O power, and almost flat gain at both L and S-bands, the defective ground structure of bias topologies is modeled and optimized. An artificial ground defect is created to offer resonant properties for the DGS of a microstrip line, which utilizes frequency-selective properties to improve the performance of the LNA circuit by suppressing the harmonics and scaling the size. The dedicated LNA shows the benefits of compact size, extremely low noise figure of 0.74/1.6 dB, high output power of 44 dBm and nearly flat gain of 14/11 dB at 1.17/2.49 GHz with the unique methodologies suggested. The compact GaN HEMT LNA could overcome the weak signal strength received by RF receiver for smart rail transport system. © 2023 Elsevier GmbHItem Indium Antimonide-Based All-Dielectric Metasurface Absorber at Terahertz Frequency for Refractive Index Sensing Applications(Institute of Electrical and Electronics Engineers Inc., 2024) Thomas, S.K.; Shenoy, A.; Satyanarayan, M.N.In this article, we present an indium antimonide (InSb)-based metasurface absorber (MA) using a complementary ring structure. The proposed MA exhibits absorption characteristics in the terahertz frequency range spanning from 1.0 to 2.2 THz. Within this frequency range, the MA demonstrates dual-band tunability, achieving approximately 100% absorption. Geometric parameters such as the outer ring radii, ring width, and InSb layer thickness are systematically adjusted to fine-tune the absorption frequency of the MA. In addition, we explore the refractive index sensing capabilities by introducing different refractive index materials into the air-filled complementary ring cavity. Notably, we achieve a peak refractive index sensitivity of 555 GHz per refractive index unit (RIU) for the first absorption peak at a minimum radius of 60 µm. © 2001-2012 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.