Browsing by Author "Raghavan, S"

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    A triangular-shaped quarter-mode substrate integrated waveguide based antenna for WBAN applications
    (Defense Scientific Information and Documentation Centre, 2018-03-13) Chaturvedi, Divya; Raghavan, S
    In this study, a compact quarter-mode substrate integrated waveguide (QMSIW) based dual-band antenna is proposed for wireless body area network applications. A QMSIW resonator is realised by splitting the full-mode substrate integrated waveguide cavity along the perfect magnetic conductor walls. The proposed antenna preserves the fundamental mode TE1I5 and the third order mode TE.Q of the square SIW cavity. The proposed antenna is linearly polarised in the lower band at 2.45 GHz and circularly polarised in the higher frequency band at 5.8 GHz. The on-body performance of the antenna is validated on a piece of pork muscle tissue and it has been found to be stable with respect to surroundings. The proposed antenna covers the ISM bands 44 MHz (2.445 GHz-2.489 GHz) and 225 MHz (5.730 GHz-5~955 GHz) at 2.45 GHz and 5.8 GHz, respectively. The measured gain of the antenna on pork tissue is 1.87 dBi and 5.5 dBi at two bands. In addition, the specific absorption rate is obtained of 0.65 m\V g and 1.51 mW/g at two bands (it∗ = 2 mm), averaged over 1 g of muscle with lOOmW input power. Moreover, the simulated and experimental results demonstrate a good agreement. © 2018, DESIDOC.
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    Coplanar waveguide-fed ultra-wideband planar antenna with WLAN-band rejection
    (Sociedade Brasileira de Microondas e Optoeletronica (SBMO), 2013-08-27) Subbarao, A; Raghavan, S
    A compact coplanar waveguide (CPW)-fed ultrawideband (UWB) antenna is proposed with band-notched characteristic. The antenna has compact size of 29 × 31 mm2. A novel wide polygon-slot is inserted on the antenna to obtain good impedance matching and wide bandwidth. A tapered radiating patch is placed inside the polygon-slot. An embedded C-slot in the radiating patch avoids potential interference from WLAN band. The antenna is fabricated and measured. The measured results confirm that the antenna has operating frequency band of 3.1-10.6 GHz with notched band of 5.1-5.9 GHz. The antenna has stable radiation patterns and consistent gain over operating band. The time domain group delay of antenna is with in 1 ns except in notched band, which indicates good linear phase response. The results indicate that the antenna is good for portable UWB systems.
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    Dual band Orthogonal Polarized 2-port MIMO Antenna for Cognitive Radio Applications
    (Advanced Electromagnetics, 2024-01-28) Mohapatra, Shubhalaxmi; Das, Satyadeep; Panda, Jyoti Ranjan; Sahu, Sudhakar; Raghavan, S
    An arrangement of orthogonally aligned antennas over two planes of a substrate is designed in this paper. The design is a novel miniaturized cognitive model operating at Long Term Evolution (LTE), C-band and X-band with sufficient band stop notch. The antenna is etched over a 0.8 mm thick FR-4 Epoxy substrate of dimension 15 mm x 15 mm. On one side the antenna is a hexagonal slotted microstrip antenna and on the other side is a partial Co-Planar Waveguide (CPW) type hexagonal patch antenna. The top hexagonal patch antenna is a wide band from 1800 MHz to 12000 MHz. With the use of a slot on the patch creates one notch from 2240 MHz to 5090 MHz and another notch is created at 6200 MHz to 8100 MHz. Thus, the working bands comprise of LTE 1900, Wi-Fi 5G and X-band under a single polarization. Similarly, the second antenna has its first resonance at LTE 1900 and the second resonance at X-band with a polarization orthogonal to the antenna at top. Being a miniaturized antenna, the cognitive radio provides gain ranging from 2.0 dB at lower frequency to 5.4 dB at higher frequency. The isolation over the operating bands suggests non-interference between the antennas. © 2024, Advanced Electromagnetics. All rights reserved.