iosr-JECE   Volume-9 ~ Issue-4 ~ July-August 2014

Abstract: Many researchers made an attempt on Beam shaping of antennas useful for different applications in surveillance and tracking radars. In the present work, synthesis of line source and linear antenna array with uniform current amplitudes and weight functions is discussed. An iterative sampling method approach is being considered for implementation. In an iterative method, original radiation pattern which is close to the desired radiation pattern is generated by a standard synthesis method and a series of correction patterns are applied to it by adding correction patterns until the convergence is achieved. The iterative method is implemented for both line source and linear array for generating cosecant and square radiation patterns and their results are compared. The patterns designed are found to exhibit minimum suitable levels and they are useful to instigate the problems of EMC.

Keywords: Line source; Radiation pattern; Sidelobe; Ripple; Desired pattern

[1]. G.S.N.Raju, Antennas and Wave Propagation, Pearson Education, 2005.
[2]. Constantine A. Balanis, Antenna Theory, 2nd ed. , New York: John wiley & Sons, Inc., 1982.
[3]. W. l. Stutzman and Gary A. Thiele, Antenna Theory and design, John wiley & Sons, Inc., U.S.A. ch.10.
[4]. S.Silver, Microwave Antenna Theory and Design, vol. 12 (M.I.T Radiation Lab. Series). New York: McGraw-Hill, 1949, pp. 466-
467.
[5]. R. E. Collin and F. J. Zucker, Antenna Theory, pt. 1. New York: McGraw-Hill, 1969, chs.5,7.

Abstract: Wireless networks offer more flexibility and adapt easily to changes in the configuration of the network. Wireless ad hoc network is a decentralized type of wireless network. Mobile ad hoc network is a type of ad hoc network, in which each and every node can change its location. Frequent link breakages exist due to its high mobility of nodes which leads to frequent path failures and route discoveries. An efficient and fundamental data dissemination mechanism is broadcasting, the mobile node blindly rebroadcasts the first received route request, even if there is no route to destination leads to broadcast storm problem.. In this paper a hybrid protocol is proposed, which combines the advantages of neighbor coverage based probabilistic rebroadcast protocol and adhoc on demand distance vector routing protocol and is simulated by Network Simulator. The neighbor coverage and probabilistic mechanism significantly decreases the number of retransmissions so as to reduce the routing overhead. Adhoc on demand distance vector routing protocol finds the shortest path to destination by evaluating the hop count. The shortest path reduces the average end to end delay more effectively. Thus hybrid protocol improves the routing performance.

Keywords: Rebroadcast delay, rebroadcast probability, connectivity factor, additional coverage ratio, shortest path

[1] Zhang X.M, Wang E.B, Xia J.J, and Sung D.K, "Neighbor Coverage based Probabilistic Rebroadcast for Reducing Routing Overhead in Mobile Ad hoc Networks‟, IEEE transactions on mobile computing, vol 12, No.3, march 2013.

[2] Buttar H.K, Chopra S.R, "Secure and Shortest Path by Modifying RREP packet of AODV protocol‟. International Journal of scientific and engineering research, Vol 4, no 12, December 2013.

[3] Zhang X.M, Wang E.B, Xia J.J, and Sung D.K,(2011) , "An Estimated Distance Based Routing Protocol for Mobile Ad Hoc Networks,‟ IEEE Trans. Vehicular Technology, Vol. 60, no. 7, pp. 3473-3484

[4] S.Y. Ni, Y.C. Tseng, Y.S. Chen, and J.P. Sheu, "The Broadcast Storm Problem in a Mobile Ad Hoc Network," Proc. ACM/IEEE MobiCom, pp. 151-162, 1999.

[5] Chen .J, Lee Y. Z, Zhou. H, Gerla. M and Shu.Y (2006), "Robust Ad Hoc Routing for Lossy Wireless Environment,‟ Proc. IEEE Conf.Military Comm.(MILCOM‟06),PP.1-7,2006

Abstract: Image compression is backbone in the field of communications and multimedia. The objective of Image compression is to minimize the size in bytes of a file by reducing the redundancy of the image data without degrading the quality of image, resulting in reduction of file size so that more images can be stored in a given amount of disk or memory space and also reduces the time required to send the images over the network [1]. In this paper we present a novel approach towards image compression based on Adaptive Neural Fuzzy inference system(ANFIS) with Differential Pulse code modulation(DPCM) in Wavelet domain so that better compression ratio can be achieved with minimum error. The overall implementation of the work consists of four steps: first, seven band wavelet. Based upon statistical properties of sub bands, different quantization and coding schemes are used. Second, first sub band is compressed using differential pulse code modulation (DPCM), the coefficient corresponding to other sub bands are compressed using Adaptive Neural Fuzzy Inference system (ANFIS). In the third stage, the result obtained is fed as input to the fuzzy vector quantizer and in fourth stage the output obtained from third stage is fed to the K means quantizer for further compression. Finally the results are compared for MSE, PSNR and the visual appearance after decoding of image.

Keywords: Image Compression, Fuzzy vector quantization, Wavelet Transform, Peak Signal to Noise Ratio, Adaptive Neural Fuzzy Inference System(ANFIS), DPCM,peak signal to noise ratio, mean square error.

[1] R. C. Gonzalez and R. E. Woods, "Digital Image Processing", 2nd Ed., Prentice Hall, 2004.

[2] Alpcan, T., Kesal, M. and Deliç, H. (1998) Wavelet Based Subband Vector Quantization Algorithm for Gray Images', Proceedings of the IASTED International Conference on Signal and Image Processing, Las Vagas, Nevada, Oct.28-31,1998, pp.720-724.

[3] Nobuhara H. and Hirota, K. (2004), ‗Color image compression/reconstruction by YUV fuzzy wavelets', IEEE Annual Meeting of the Fuzzy Information, Vol.2, Pp. 774 – 779.

[4] Khalid W. Alnaji and Waseam M.Ashour(2011), ‗A Novel Clustering Algorithm Using K-means (CUK)', International Journal of Computer Applications © 2011 by IJCA Journal,1 - Article 3.

[5] Mrs. S.Sujata, Mrs. A. Shanthi Sona(2013), ‗New Fast K-Means Clustering Algorithm using Modified Centroid Selection Method', International Journal of Engineering Research & Tech., Vol.2/Issue 2.

Abstract: MEMS Micromirrors are used in various applications like Digital light projector (DLP), Highdefinition (HD) display, endoscopic Optical Coherent Tomography and also in defense applications. This paper deals with the analysis of structural mechanical properties of electrostatically driven prestressedMicromirrorusing COMSOL Multiphysics 4.3b software. The proposed design was compared for the lift-off stress generated at the edges due to the plating process and the associated displacement at a given prestress level.

Keywords: MEMS, Micromirrors, Cantilever,COMSOLMultiphysics, Serpentine beam.

[1]. A COMSOL Model to Analyse the Structural Mechanical Problem in an Electrostatically Controlled Prestressed Micro-Mirror; HazianMamat, AzrulAzlanHamzah, (et.al); World Applied Sciences Journal 26 (7): 950-956, (2013).
[2]. Design and Optimization of an All Optically Driven Phase Correction MEMS Deformable Mirror Device using Finite Element Analysis;V. Mathur ,K. Anglin, V.S. Prasher (et.al) Proceedings of the COMSOL Conference (2009) at Boston.
[3]. MEMS Electrostatic comb actuators with different configurations: A comparison of structure design and materials using COMSOL 3.5a; Swati Kapoor, Dinesh Kumar, (et.al) Proceedings of the COMSOL Conference (2011) at Bangalore.
[4]. COMSOL 4.2a Model Micromirror.
[5]. Design and Analysis of the performance of a Torsional Micromirror for an Optical switching system, Ajay A. Kardak*, Prasant Kumar Patnaik, (et.al); National MEMS Design Centre, Indian Institute of Science, Bangalore.

Abstract: A method to improve the directivity of the microstrip coupler is presented. The width of the coupler is modified for phase velocity compensation which results in high directivity. Using this procedure, a 15 dB coupler is designed and simulated at 0.9 GHz using SONNET software. A high directivity of 46 dB is obtained. The validity of the design concept is verified and compared with conventional coupler by simulations.
Keywords: coupled lines, directional coupler, microstrip, and microwave.

[1]. A. Podell, "A high directivity microstrip coupler technique," in IEEE MTT-S Int. Microw. Symp. Dig., pp.33-36, May, 1970.
[2]. M. Dydyk, "Microstrip directional couplers with ideal performance via single-element compensation," IEEE Trans. Microw. Theory Tech., vol.47, no. 6, pp. 956–964, Jun. 1999.
[3]. R. Phromloungsri, M. Chongcheawchamnan, and I. D. Robertson, "Inductively compensated parallel coupled microstrip lines and their applications," IEEE Trans. Microw. Theory &Tech., vol.54, no.9, pp.3571–3582, Sep.2006.
[4]. S. Lee and Y. Lee, "An inductor-loaded microstrip directional coupler for directivity enhancement," IEEE Microw. Wireless Compon. Lett., vol. 19, no. 6, pp. 362–364, Jun. 2009.

[5]. S.-F. Chang, J.-L. Chen, Y.-H. Jeng and C.-T. Wu, "New high-directivity coupler design with coupled spurlines," IEEE Microw. Wireless Compon. Lett., vol. 14, no. 2, pp. 65–67, Feb. 2004.

Abstract: The paper present design of microstrip patch antenna at 2.4 GHz. Further by introducing fractal concept to the star-shaped microstrip antenna Koch curve antenna is designed. The Koch island fractal patch antenna is introduced in order to reduce the antenna size. By space-filling property of fractal geometry, this antenna reveals lower resonant frequency. Based on experimental result, it is found that as iteration and iteration factor increases, the resonant frequency of this patch antenna decreases. Broad band operation with size reduction is obtained. To improve efficiency and bandwidth suspended configuration is used. A comparison of fractal antenna with conventional microstrip patch antenna is made regarding the bandwidth, return loss, VSWR, and gain. The antenna is simulated by the HFSS software.(High frequency structure simulator).

Keywords: Bandwidth enhancement, Fractal geometry, HFSS, Microstrip patch antenna, Koch curve

[1]. Divya Dixit Saxena and Ankur Kumar Tripathi "Fractal based microstrip patch antenna in wireless communication".
[2]. Ms.Priyanka, Mr. Navin Srivastava, "Bandwidth enhancement for microstrip patch antenna using suspended techniques for wireless applications "International Journal of Advancements in Research & Technology,Volume2, Issue5, May-2013.
[3]. Indrasen Singh, Dr. V.S. Tripathi "Micro strip Patch Antenna and its Applications: a Survey".
[4]. Shubhangi S. Ghorpade Vidya B. Babare V. U. Deshmukh "Comparison Of E-Shape Microstrip Antenna And E-Shape Fractal Antenna".
[5]. M. Ramkumar Prabhu, V. Reji and 3A. Sivabalan "Improved Radiation and Bandwidth of Triangular and Star Patch Antenna" Research Journal of Applied Sciences, Engineering and Technology 4(12): 1740-1748, 2012

Abstract: Several excitations are possible either for line sources or arrays of different radiating elements. However, in this work, different types are considered and radiation patterns are numerically computed. It has been possible, to generate low sidelobe, low beamwidth patterns. The patterns are extremely useful in high resolution radars, and EMC systems.

[1]. G. S. N. Raju, Antennas and Wave Propagation, Pearson Education, 2005.
[2]. Mailloux, R. J., Phased Array Antenna Handbook, Artech House, Boston, 1994.
[3]. Balanis, C.A., Antenna Theory: Analysis and Design, John Wiley and Sons, 1982.
[4]. Qu. Y. G. Liao. S.-Q.Zhu, and X.-Y. Liu, ―Pattern synthesis of planar antenna array via convex optimization for airborne forward
looking radar,‖ Progress In Electromagnetics Research, Vol. 84, pp. 1 -10, 2008.
[5]. W. L. Stutzman & G. A. Thiele, Antenna Theory and Design, John Wiley, 1981.
[6]. T. T. Taylor, ―Design of line source antennas for narrow beam width and low sidelobes‖, IRE Trans. Antenna and propagation, Vol.
AP-3, pp. 16-28, January 1955.

Abstract: This paper presents the design and implementation of Modified Booth encoding multiplier for both signed and unsigned 32 - bit numbers multiplication. The already existed Modified Booth Encoding multiplier and the Baugh-Wooley multiplier perform multiplication operation on signed numbers only. Whereas the array multiplier and Braun array multipliers perform multiplication operation on unsigned numbers only. Thus, the requirement of the modern computer system is a dedicated and very high speed unique multiplier unit for signed and unsigned numbers. Therefore, this paper presents the design and implementation of SUMBE multiplier. The modified Booth Encoder circuit generates half the partial products in parallel. By extending sign bit of the operands and generating an additional partial product the SUMBE multiplier is obtained. The Carry Save Adder (CSA) tree and the final Carry Look ahead (CLA) adder used to speed up the multiplier operation. Since signed and unsigned multiplication operation is performed by the same multiplier unit the required hardware and the chip area reduces and this in turn reduces power dissipation and cost of a system.

Index Terms: Modified Booth Encoding multiplier, Baugh-Wooley multiplier, array multiplier, CSA, CLA Partial product, Signed-unsigned.

[1]. Ravindra P Rajput and M.N Shanmukka Swamy, "High Speed Modified booth encoder Multiplier for signed and unsigned numbers" IEEE 2012 14th International conference on modeling & simulation.
[2]. W. –C. Yeh and C. –W. Jen, "High Speed Booth encoded Parallel Multiplier Design," IEEE transactions on computers, vol. 49, no. 7, pp. 692-701, July 2000.
[3]. Shiann-Rong Kuang, Jiun-Ping Wang, and Cang-Yuan Guo, "Modified Booth multipliers with a Regular Partial Product Array," IEEE Transactions on circuits and systems-II, vol 56, No 5, May 2009.
[4]. Li-Rong Wang, Shyh-Jye Jou and Chung-Len Lee, "A well-structured Modified Booth Multiplier Design" 978-1-4244-1617-2/08/$25.00 ©2008 IEEE.
[5]. Soojin Kim and Kyeongsoon Cho "Design of High-speed Modified Booth Multipliers Operating at GHz Ranges" World Academy of Science, Engineering and Technology 61 2010