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Inamdar K.,Sardar Vallabhbhai National Institute of Technology, Surat | Kosta Y.P.,Marwadi Education Foundation Group of Institutions | Patnaik S.,Xavier Institute of Engineering
Radioelectronics and Communications Systems | Year: 2015

Metamaterials have been an attractive topic for research in the field of electromagnetics in recent years. In this paper, a criss-cross structure has been suggested; this shape has been inspired from the famous Jerusalem Cross. The software analysis of the proposed unit cell structure has been validated experimentally thus giving negative response of ɛ and μ. Following this, a microstrip patch antenna based on suggested metamaterial has been designed. The theory and design formulas to calculate various parameters of the proposed antenna have been presented. The design of a metamaterial based microstrip patch antenna has been optimized for providing of an improved gain, bandwidth and multiple frequency operations. All the antenna performance parameters are compared and presented in table and response-graphs. Also it has been observed that the physical dimensions of the metamaterial based patch antenna are smaller compared to its conventional counterpart operating in the same frequency band. The response of the patch antenna has been verified experimentally either. The important part of the research was to develop metamaterial based on some signature structures and techniques that would offer advantage in terms of bandwidth and multiple frequency operation, that is demonstrated in the paper. The unique shape suggested in this paper provides an improvement in bandwidth without reducing the gain of the antenna. © 2015, Allerton Press, Inc. Source

Patel V.A.,Essar Steel India Ltd. | Jain S.V.,Nirma University | Motwani K.H.,Marwadi Education Foundation Group of Institutions | Patel R.N.,Nirma University
Procedia Engineering | Year: 2013

The main limitation of centrifugal pump running in turbine mode is lower efficiency at part load operating conditions as compared to conventional hydro turbines. To enhance the utilization of pump as turbine (PAT) in mini/micro hydropower plants, it is very important to improve its performance with some low cost modifications. The part load efficiency of PAT can be improved by guiding the flow at part load by installing the movable guide vanes. However, to avoid the higher cost of movable guide vanes, it was proposed to install fixed guide vanes. The existing volute casing of centrifugal pump was not having sufficient space for provision of guide vane mechanism. Hence, to create an additional space the existing impeller of 250 mm dia. was replaced by 200 mm dia. impeller which has facilitated an additional space for installation of guide vanes. To determine the optimum position of fixed guide vanes, CFD analysis of casing was carried out with NACA-4418 profile by varying the guide vane angles between 45° to 80°. The numerical simulations were carried out using Reynolds averaged Navier-Stokes (RANS) equations with standard k-ε turbulence model under steady state conditions. In addition, it was required to place the reducer between the service pump and PAT as the pipe dia. at service pump outlet was 5" and at PAT inlet was 3". To optimize the shape and location of reducer between service pump and PAT, CFD analysis was performed by considering two different reducers at different locations. PAT with 200 mm dia. impeller and 8 numbers of fixed guide vanes provided at 75° angle led to improved performance of PAT. Also the long reducer provided at the inlet of PAT was subjected to less head drop in the piping system. © 2012 Published by Elsevier Ltd. Source

Patel S.K.,University of Nebraska - Lincoln | Argyropoulos C.,University of Nebraska - Lincoln | Kosta Y.P.,Marwadi Education Foundation Group of Institutions
Waves in Random and Complex Media | Year: 2016

We present microstrip patch antenna loaded with multiple split ring resonator substrate and superstrate. We analyze how the loading of split ring resonator superstrate and substrate can improve the bandwidth compared to the simple microstrip patch antenna and microstrip patch antenna loaded with split ring resonator superstrate. Another important observation is made for multiple split ring resonator loading in superstrate and substrate of microstrip patch antenna. The design is compared for two, three, and four-ring split ring resonator loading. The designs are also compared for different gap spacing between the rings. All three designs are compared for small gap and large gap between the rings. The design results in the form of reflection coefficient and bandwidth is presented in this manuscript. The design results are also compared with previously published designs. © 2016 Informa UK Limited, trading as Taylor & Francis Group Source

Patel S.K.,Sudan University of Science and Technology | Kosta Y.P.,Marwadi Education Foundation Group of Institutions
Journal of Modern Optics | Year: 2014

We have introduced metamaterial superstrate in microstrip-based radiating structure to increase its bandwidth. Split ring resonators are added as metamaterial metallic inclusion in superstrate of the conventional design. This changes the basic structure of the material. Material properties such as permittivity and permeability changed due to change in the structure. The change in its material properties enhances the bandwidth of the antenna. The antenna is meandered to achieve better performance at the edges which in a way improve the radiation path of the patch. Here, the proposed antenna works on three bands in the range 3-8 GHz. Maximum 60% bandwidth is enhanced in the third band. The voltage standing wave ratio and return loss (S11) of the entire three bands are shown in the paper. The antenna works on 3.51, 4.86 and 7.8 GHz. Design results are obtained by high-frequency structure simulator which is used for simulating microwave passive components. © 2014 Taylor & Francis. Source

Motwani K.H.,Marwadi Education Foundation Group of Institutions | Jain S.V.,Nirma University | Patel R.N.,Nirma University
Procedia Engineering | Year: 2013

The energy scenario in rural, remote and hilly areas of India is characterized by inadequate, poor and unreliable supply of energy services. In such regions, the load density is low and extension of grid system is totally uneconomical, hence the small hydropower schemes can provide a solution for the energy problems besides solar photovoltaic, which is not available throughout the day. The main hindrance in implementing such hydropower schemes is high initial cost of conventional hydro turbines. The cost of these plants can be brought down by using centrifugal pump in turbine mode in context of various advantages associated with the pumps viz. low initial and maintenance cost, ready availability, simple construction etc. However, the efficiency of pump as turbine (PAT) is lower than that of conventional hydro turbines. For commercial justification of PAT technology, a cost analysis of 3 kW capacity pico hydropower plant was carried out by considering PAT and Francis turbine as a prime mover. The hydro turbine test rig was developed by installing PAT and its performance characteristics were plotted. The annual life cycle cost (ALCC) analysis was carried out based on initial cost of the project, capital recovery factor and annual expenses. Based on the analysis, the ALCC and the cost of electricity generated per unit were found to be very less for PAT than that of Francis turbine, which has justified the use of PAT for the case under consideration. © 2012 Published by Elsevier Ltd. Source

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