Mathur D.,Government Engineering College |
Bhatnagar S.K.,SKIT |
Sahula V.,Malaviya National Institute of Technology, Jaipur
IEEE Antennas and Wireless Propagation Letters | Year: 2014
This letter presents a new method for quickly estimating the physical dimensions of a rectangular microstrip antenna (RMSA). This is based on the newly introduced concept of 'Equivalence of Design' for RMSA. Two designs are said to be equivalent if they result in the same resonance frequency. This is an outcome of Bhatnagar's postulate. It relates the classical extension in length ΔL with the length and width of the patch apart from the substrate thickness. This letter emphasizes the importance of substrate thickness normalized with respect to guided wavelength. This is termed as the 'H' parameter. For RMSA, this is the key parameter rather than the individual parameters - dielectric constant (εr), substrate thickness (h), or resonance frequency (fo). A new parameter - the scaling factor (ψ) - has been introduced and defined. Based on these, transformation laws have been put forward. These can be used for quickly estimating the RMSA design parameters from a 'known good design.' The laws have been verified by estimating physical parameters of RMSA and then calculating its resonance frequency. This has been repeated for several hundred designs. The matching has been excellent. Simulation and measurement results of a known good design (Design1) and one of the transformed designs (Design3) are also presented. The results of the transformed design are in good agreement with those of Design1 considering fabrication and measurement tolerances. © 2002-2011 IEEE.
Kaushik A.,Banasthali University |
Dalela B.,SKIT |
Rathore R.,University of Kota |
Vats V.S.,Government College |
And 4 more authors.
Journal of Alloys and Compounds | Year: 2013
A systematic investigation on the synthesis, characterization, optical and magnetic properties of Co doped ZnO nanocrystals have been reported. Nanocrystals of Zn1-xCoxO (where x = 0.05 and 0.10) were synthesized using the Sol-gel technique. Structural, optical and magnetic properties of the samples were investigated by X-ray diffraction (XRD), UV-VIS-NIR spectroscopy, Raman spectroscopy and SQUID magnetometer. Energy dispersive X-ray, Scanning electron microscopic, XRD and Raman measurements showed that the Co ions were successfully doped at the Zn site in the wurtzite type ZnO lattice. An appreciable blue shift in the absorption spectrum was observed, which indicates that the Co doping in ZnO leads to systematic increase in the band-gap with dopant concentration. Magnetization studies showed that the Co doped ZnO nanocrystals display room temperature ferromagnetism and the ferromagnetic ordering strengthens with the Co concentration. © 2013 Elsevier B.V. All rights reserved.
Satyanarayana Moorthy D.V.,SVUCE |
Reddy Babu G.,SKIT
Journal of Engineering and Applied Sciences | Year: 2010
Textile manufacturing units involved in finishing processes are profuse water consumers. The effluents from these plants are major source of water pollution. Poly Aluminium Chloride (AlCl3 6H2O) is used as a coagulant for the removal of Chemical Oxygen Demand (COD) of selective reactive dyes, which are used for cotton yarn dyeing, at different doses. The results indicate that the removal of COD of various dyes RB41, RB209, RB204 and RB184 are 68, 40, 36, and 29 percent, respectively at their optimum doses. The optimum doses of Poly Aluminium Chloride (PAC) for RB41, RB209, RB204 and RB 184 are 5.2, 34.3, 20 and 22mg of PAC per mg. of COD removed, respectively. © 2006-2010 Asian Research Publishing Network (ARPN). All rights reserved.
Vijayalaxmi M.,SKIT |
Narayana Reddy S.,SVU
Lecture Notes in Electrical Engineering | Year: 2016
In high speed data transmission, Orthogonal Frequency Division Multiplexing (OFDM) is a spectrally proficient method over multipath fading channel. This OFDM signal suffers from high Peak-to-average power ratio (PAPR) and Bit Error Rate (BER) (Van Nee and de Wild, Vehic. Technol. Conf. 3:2072– 2076, 1998) . MIMO OFDM configuration step-up the capacity of the system and diversity gain on frequency selective and time variant channels. Preference is on SFBC-MIMO-OFDM to operate fading channel much more effectively. Constant Modulus Algorithm (CMA) is highly proficient technique for alleviating high PAPR. But the main demerit associated with CMA is slow convergence rate, extensive steady state mean square error (SSMSE), and phase blind nature. We propose an enhanced modified constant modulus algorithm (MCMA) where the step size is carefully assessed to maintain a balancing between convergence rate and final accuracy. Simulations demonstrates the efficiency of proposed MCMA. © Springer India 2016.
Vijayalaxmi M.,SKIT |
Narayana Reddy S.,SVU
International Journal of Applied Engineering Research | Year: 2015
In this paper, we proposed an iterative receiver for MIMOOFDM systems. Based on this receiver, solutions to two of the most important problems in OFDM systems have been provided, namely, inter carrier interference cancellation and inter symbol interference cancellation over time-selective and frequency-selective fading channels. In this topic we consider an SFBC-OFDM system with timing offset (µ), derive the mathematical expressions for the interference provoked and propose the interference cancelling receiver. The influence of timing offset (µ) on a MIMO OFDM system has been derived theoretically and evaluated from results of bit error rate (BER) simulations. © Research India Publications.