Sarin, V. P.
Pradeep, Anju
Jayakrishnan, M. P.
Chandroth, Aanandan
Mohanan, P.
Kesavath, Vasudevan
The detailed experimental and simulation studies of the stacked dogbone metamaterial particles are presented in this article. Besides the conventional left handed propagation mode, it is observed that the structure supports Fabry-Perot resonant modes and the excitation of this mode can be identified from the right handed resonant tunnel band in the dispersion diagrams. It is shown that the coupling between the Fabry-Perot and left handed resonant modes gives flat tunnel band characteristics in the dispersion diagram and is associated with huge electromagnetic absorption. The spectral response can be tailored by varying the stacking thickness of the sample making it suitable for microwave absorption and left handed transmission applications. (c) 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1347-1353, 2016
Sarin, V. P.
Jayakrishnan, M. P.
Aanandan, C. K.
Mohanan, P.
Vasudevan, K.
The extraordinary optical transmission (EOT) through an array of holes in a metal plate has been a constant source of inspiration for researchers for over a decade (Ebbesen et al 1998 Nature 391 667-9). In this paper, an EOT analogue is proposed in the microwave frequency range for enhancing the radiation performance of a stacked dipole antenna. It is observed that the back radiated power of the antenna is considerably reduced and the reason behind transmission enhancement is the excitation of Fabry-Perot resonant modes on the slit loaded aperture. Computational analysis based on finite difference time domain is performed for identifying the true reason behind resonant transmission enhancement.
Sarin, V. P.
Jayakrishnan, M. P.
Vinesh, P. V.
Aanandan, C. K.
Mohanan, P.
Vasudevan, K.
The quest for invisibility has inspired a deep ardour in the research community over the past decade. The invention of metamaterials has boosted the research on electromagnetic cloaking due to its unusual electromagnetic parameters under plane wave incidence. In this study, we propose a novel cloaking scheme, using dogbone metamaterials, for effectively routing the incident electromagnetic fields around a target metal cylinder under consideration. Notable reduction in the scattered power is observed from the target in comparison to an uncloaked target. Experiments and simulations validate an effective reduction in the scattering cross section of the target and effective guiding of the incident plane wave around the target.
Sarin, V. P.
Nishamol, M. S.
Tony, D.
Aanandan, C. K.
Mohanan, P.
Vasudevan, K.
A broadband L-strip fed printed microstrip antenna is presented. The strip loaded slotted broadband microstrip antenna is fed by an L-strip feed line to achieve impedance matching for the higher order modes of the patch antenna in addition to the existing resonances. The antenna offers 74% bandwidth when printed on a substrate of dielectric constant 4.2 and has an overall dimension of 42 X 55 X 3.2mm(3). The simulated and experimental reflection characteristics of the antenna with and without the L-feed along with radiation patterns, input impedance variations, gain and efficiency of the final antenna are presented and discussed. The time domain transient analysis indicates a minimum dispersion to the transmitted pulse.
Sarin, V. P.
Nassar, Nisha
Deepu, V.
Aanandan, C. K.
Mohanan, P.
Vasudevan, Kesavath
A simple electromagnetically coupled wideband printed microstrip antenna having a 2: 1 VSWR bandwidth of 38% covering the 5.2/5.8-GHz WLAN, HIPERLAN2, and HiSWANa communication bands is presented. The large bandwidth is obtained by adding a rectangular metal strip on a slotted square microstrip antenna. The antenna occupies an overall dimension of 42 x 55 x 3.2 mm(3) when printed on a substrate of dielectric constant 4. It exhibits good radiation characteristics and moderate gain in the entire operating band. Details of the design along with experimental and simulation results are presented and discussed.
Nisha, M. S.
Sarin, V. P.
Gijo, Augustin
Deepu, V.
Anandan, C. K.
Mohanan, P.
Vasudevan, Kesavath
A new design of a compact single-feed dual frequency dual polarized microstrip antenna with an X-slot is presented. The proposed antenna generates two orthogonally polarized radiations with center frequencies at 1.42 GHz and 1.79 GHz, respectively. . For fixed dual frequency operation, the antenna has an area reduction of 74% and 59% for the respective frequencies compared to standard rectangular patches. The antenna exhibits broadside radiation pattern and has sufficient gain for the two hands. (c) 2008 Wiley Periodicals. Inc. Microwave Opt Technol Lett 50: 3198-3201 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23903
Nishamol, M. S.
Sarin, V. P.
Tony, D.
Aanandan, C. K.
Mohanan, P.
Vasudevan, Kesavath
A compact design of a single feed microstrip antenna for circular polarization (CP) is proposed and studied. CP is brought about by embedding a slot in a cross shaped patch. The structure. enables an area reduction of 46% as compared to conventional rectangular microstrip antenna. The antenna offers a 2:1 VSWR bandwidth from 1.53 to 1.61 GHz on a substrate of dielectric constant 4.4 and height 1.6 mm with a broadside radiation characteristic in the entire band. The 3 dB axial ratio bandwidth of the antenna is 5% with moderate gain that covers global positioning system (GPS) L1 band. Simulation and experimental results of the antenna are presented and discussed. (C) 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:468-470, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25706
Sarin, V. P.
Nishamol, M. S.
Tony, D.
Aanandan, C. K.
Mohanan, P.
Vasudevan, K.
A broadband printed microstrip antenna having cross polarization level > 15 dB with improved gain in the entire frequency band is presented. Principle of stacking is implemented on a strip loaded slotted broadband patch antenna for enhancing the gain without affecting the broadband impedance matching characteristics and offsetting the position of the upper patch excites a lower resonance which enhances the bandwidth further. The antenna has a dimension of 42 x 55 x 4.8 mm(3) when printed on a substrate of dielectric constant 4.2 and has a 2: 1 VSWR bandwidth of 34.9%. The antenna exhibits a peak gain of 8.07 dBi and a good front to back ratio better than 12 dB is observed throughout the entire operating band. Simulated and experimental reflection characteristics of the antenna with and without stacking along with offset variation studies, radiation patterns and gain of the final antenna are presented.
Nishamol, M. S.
Sarin, V. P.
Tony, D.
Aanandan, C. K.
Mohanan, P.
Vasudevan, K.
An electronically reconfigurable microstrip antenna with circular and linear polarization switching is presented. The prototype fabricated on a substrate of dielectric constant (epsilon(r)) 4.4 and height (h) 1.6 mm is fed by a proximity feed fabricated using the same substrate. By controlling the bias voltage of two PIN diodes, the polarization of the antenna can be switched between three states; two states for linear polarization (horizontal and vertical) and one state for circular polarization (RHCP). Simulation and experimental results show that the proposed antenna has a cross polar level better than 10 dB in the linear polarization state and 18 MHz axial ratio bandwidth in the circular polarization state. The frequency and polarization diversities of this design could potentially improve the reliability of wireless communication systems.
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