INTERNATIONAL JOURNAL OF MICROWAVE AND OPTICAL TECHNOLOGY

VOL. 5, NO. 3, MAY 2010
A PUBLICATION OF THE
INTERNATIONAL ACADEMY OF MICROWAVE AND OPTICAL TECHNOLOGY (IAMOT)
Reno, NV 89511, U.S.A.
MAY 2010 VOLUME 5 NUMBER 3 IJMOT ISSN: 1553-0396
Banmali S Rawat

Editor-In-Chief

MESSAGE FROM EDITOR-IN-CHIEF
MICROWAVE RELATED PAPERS
Manuscript Title:Suspended Microstrip Patch Antenna for Wireless Applications
Manuscript Id:IJMOT-2009-9-468
Abstract:In this paper suspended Microstrip Patch\r\nAntenna with inverted V-shaped ground plane is\r\npresented. The fundamental parameters of the\r\nantenna such as return loss, gain, radiation pattern\r\nand polarizations are simulated, measured and these\r\nparameters meets the acceptable antenna standards.\r\nThe radiation patterns are bidirectional in the Eplane\r\nand H-plane. The analysis is performed\r\nnumerically using method of moments simulation\r\nsoftware (Zeland- IE3D version 12.0) and the\r\nexperimental results are presented.
Authors:T.Shanmuganantham, Dr. S. Raghavan
Submitted On:9/03/2009
Pages:115-118
Action: [Full Paper] No. of Downloads: 9
Manuscript Title:Suspended Hexagonal Microstrip Antennas for Circular\r\nPolarization
Manuscript Id:IJMOT-2009-9-471
Abstract:Suspended hexagonal microstrip antenna\r\nwith a single coaxial feed has been proposed for\r\ncircular polarization. The configuration has been\r\nrealized by inserting perturbations along two\r\nopposite sides of the suspended hexagonal\r\nmicrostrip antenna. The broad bandwidth of 70\r\nMHz has been obtained corresponding to VSWR <\r\n2 and 3 dB axial ratio bandwidth of 16.2 MHz has\r\nbeen achieved for the suspended antenna which is\r\ndesigned at 915 MHz. Theoretical results have been\r\nvalidated with experiments.
Authors:K. P. Ray, D. M. Suple and N. Kant
Submitted On:9/10/2009
Pages:119-123
Action: [Full Paper] No. of Downloads: 14
Manuscript Title:Dual-band Slot Loaded Circular Disk Patch Antenna for WLAN Application
Manuscript Id:IJMOT-2009-9-473
Abstract:Analysis of two parallel slots embedded in circular disk patch antenna has been presented. The proposed antenna exhibits dual-band behaviour working at 2.93 and 3.52 GHz suitable for WLAN application. The effect of slot dimension in the patch has been studied. Slot length and substrate thickness have significant effect on frequency ratio f2/f1. Typically the frequency ratio is found 1.20 for given value of slot dimensions. Calculated results show good agreement with the simulated data obtained from IE3D.
Authors:J. A. Ansari, Anurag Mishra, N. P. Yadav and P. singh,
Submitted On:10/01/2009
Pages:124-129
Action: [Full Paper] No. of Downloads: 12
Manuscript Title:Design of a Coupled-Line Filter: An Implicit Space Mapping with Extra Mapping Approach
Manuscript Id:IJMOT-2009-11-450
Abstract:Using the implicit space mapping method together with an extra mapping, the design parameters for a case-study application are determined, in this paper. The main advantage of this technique is that it can decrease the number of fine model evaluations. First, the coarse model is optimized to obtain design parameters satisfying the design objective. Next, an auxiliary set of parameters, which always remain fixed in the fine model, are calibrated in the coarse model to match coarse and fine model responses. Considering the re-calibrated auxiliary parameters fixed, then, the improved coarse model is re-optimized to obtain a new set of design parameters. Finally, these design parameters are given to the fine model to evaluate its performance. When a satisfactory solution is reached, the procedure is stopped. The case-study application is a coupled-line filter with a resonant frequency of 36 GHz. Simulation results show that only two evaluations of the fine model are sufficient to get satisfactory results for this application.
Authors:Saeed Tavakoli, Mahdieh Zeinadini and Shahram Mohanna
Submitted On:11/05/2009
Pages:130-133
Action: [Full Paper] No. of Downloads: 7
Manuscript Title:Polarized Switchable Microstrip Array Antenna Printed on\r\nLiTi Ferrite
Manuscript Id:IJMOT-2009-11-452
Abstract:Radiation characteristics of a polarized\r\nswitchable microstrip planar array of circular patch\r\nantenna printed on synthesized LiTi ferrite\r\nsubstrate with a normal magnetic bias field are\r\nanalysed. Normaly upto X-band, the em-waves\r\npropagation is studied by the Pozar’s quasi TEM\r\nwaves (extraordinary waves) but for the study in Xband\r\nspin wave exchange term (?r) in the\r\nmagnetostatic wave analysis is also incorporated\r\nwhich depends upon the static internal field (Hex).\r\nThe substituted polycrystalline ferrite with DC\r\nmagnetic biasing is offers number of novel magnetic\r\nand electrical characteristics including switchable\r\nand polarized radiations from a microstrip antenna.\r\nIn such a case of antenna radiation, most of the\r\npower will be converted into mechanical waves and\r\nlittle radiates into air. Under such condition the\r\nantenna become switch off, in the sense of effectively\r\nabsence as radiator.
Authors:Naveen Kumar Saxena, Nitendar Kumar, Pradeep Kumar Singh Pourush and Sunil Kumar Khah
Submitted On:11/05/2009
Pages:134-139
Action: [Full Paper] No. of Downloads: 14
Manuscript Title:Analysis of Broadband operation with Parasitic Elements in Single and two Layer structures
Manuscript Id:IJMOT-2009-11-456
Abstract:In this paper analysis of disk patch antenna with two parasitic elements in single layer as well as in two layer configurations is presented. The bandwidth of the antenna significantly depends on gap separation (s) and thickness h1and h2. Bandwidth of the antenna in single layer gap coupled structure is found 18.09 % (485 MHz) and it improves up to 36.50 % (985 MHz) in two layer patch. Further an enhanced radiation of 4.93 dB is achieved in two layer patch as compared to simple disk patch. The theoretical results obtained from the analysis are compared with IE3D simulated results which are in good agreement
Authors:J. A. Ansari, N. P. Yadav and P. singh
Submitted On:11/05/2009
Pages:140-147
Action: [Full Paper] No. of Downloads: 7
Manuscript Title:Analysis and design of broad-band Square-to-Circular\r\nWaveguide Transitions
Manuscript Id:IJMOT-2009-11-266
Abstract:This paper presents the design of\r\nsquare-to circular waveguide transitions. The\r\ndesign is based on the asymmetric rectangular-tocircular\r\nand circular-to-circular waveguide\r\njunction) associated with the generalized S-matrix\r\ntechnique for the composite structure. The\r\nperformances of initial and optimized transitions\r\nare presented. A transition from square to\r\ncircular waveguide provides 30dB return loss\r\nbetween 10GHz and 12GHz, which shows that\r\nmore sections are required for broad-band\r\ntransitions. Design and analysis procedure is\r\nperformed through the commercially available\r\nfield solver HFSS and CST, which is in good\r\nagreement with experimental results.
Authors:Vivek Yadav, Udaybir Singh and AK Sinha
Submitted On:11/12/2009
Pages:148-151
Action: [Full Paper] No. of Downloads: 8
Manuscript Title:Transistor Device Optimization for RF Power Amplifier Employing Rapid\r\nEnvelope Load-Pull System
Manuscript Id:IJMOT-2009-12-488
Abstract:This paper reports mathematical explanation\r\nand the application domain of rapid envelope load-pull\r\nsystem. It is demonstrated that this novel load-pull\r\ntechnique finds immediate use in the optimization of\r\ntransistor devices for the design of microwave power\r\namplifiers. The limitations of the existing load-pull systems\r\nseverely affect the overall performance optimization of\r\ntransistor devices. The envelope load-pull improves on the\r\nlimitations of the existing systems and thus provides a very\r\neffective methodology for the design and investigation of\r\nthe RF power amplifiers. Initially the paper describes the\r\nmathematical foundation of the envelope load-pull concept\r\nand then the rapid, accurate and reliable measurement\r\ncapability of the system is presented. It clearly vindicates\r\nthe potential areas of application of the system in\r\nimproving the measurement throughput and yield\r\noptimization of the microwave devices. Finally, the\r\nharmonic envelope load-pull is utilized on a commercially\r\navailable 1W GaAs FET that demonstrates the rapid RF\r\npower amplifier design, investigation and optimization\r\nstrategy.
Authors:Mohammad S. Hashmi*, Member IEEE; Paul J. Tasker**, Senior Member IEEE; and Fadhel M.\r\nMohammad S. Hashmi*, Member IEEE; Paul J. Tasker, Senior Member IEEE; and Fadhel M.Ghannouchi
Submitted On:12/2/2009
Pages:152-161
Action: [Full Paper] No. of Downloads: 6
OPTICAL RELATED PAPERS
Manuscript Title:A Simple Design of a Monochromator by Cascading Photonic Band-Gap Filters
Manuscript Id:IJMOT-2009-9-475
Abstract:The article presents a design of a monochromator using photonic bang gap structures in the ultraviolet region of electromagnetic spectrum. Here, how a simple design enables one to achieve a monochromator by cascading the three photonic band gap structures has been presented. This idea is based on the Kronig-Penny model in band theory of solids. We can achieve the desired wavelength of light by choosing appropriate values of controlling parameters. In this study, we take the alternate layers of air and Ge.
Authors:Vipin Kumar, K. S. Singh. S. P. Ojha
Submitted On:10/01/2009
Pages:162-165
Action: [Full Paper] No. of Downloads: 8
Manuscript Title:Characteristic Analysis of Traveling Wave Electrooptic Modulators on Lithium Niobate Substrate
Manuscript Id:IJMOT-2009-11-462
Abstract:The characteristic analysis of traveling wave electrooptic modulators on z-cut and x-cut lithium niobate substrates is carried out by using the finite element method based on a quasi-TEM approximation. The microwave effective index, the characteristic impedance, and the frequency dependent attenuations are calculated. The optical frequency response is also calculated and hence the 3-dB optical bandwidth is estimated. The bandwidth increases significantly for simultaneous velocity and impedance matching but is limited by the microwave losses in the dielectric material. Also, the unequal gap-width between the electrodes on a z-cut LiNbO3 substrate significantly affects the highest achievable bandwidth of the modulator. Optical 3-dB bandwidth of more than 140 GHz can be achieved with x-cut LiNbO3 substrate, when two backside slots are incorporated in the structure.
Authors:M. Shah Alam, M. Khaled Hassan, and M. Sakawat Ali
Submitted On:11/08/2009
Pages:166-175
Action: [Full Paper] No. of Downloads: 8
Manuscript Title:Polarization Mode Dispersion Mitigation through Spun Fibers
Manuscript Id:IJMOT-2009-11-464
Abstract:Polarization mode dispersion (PMD) in\r\nsingle mode fibers is one of the main limiting\r\nfactors for high speed optical communication\r\nsystem especially for systems with bit rates of 40-\r\nGbps and beyond. PMD occurs because of the\r\nexistence of the birefringence, which is due to slight\r\nelliptical nature of the core and asymmetric\r\nstresses along the fibers. Thus propagating light is\r\nsplit into two local polarization modes that travel\r\nwith different velocities. The resulting difference in\r\npropagation times between the two polarizationmodes\r\nis known as differential group delay (DGD).\r\nSpinning the fiber during the drawing process\r\nreduces the differential group delay and hence the\r\npolarization mode dispersion. This article presents\r\nthe numerical simulation of polarization\r\nmaintaining fibers and spun fibers. Simulation\r\nresults show that the spun fibers have less\r\ndifferential group delay compared to the un-spun\r\nfibers and thus reducing the effect of polarization\r\nmode dispersion in single mode fibers.
Authors:Dowluru Ravi Kumar, Dr. B. Prabhakara Rao
Submitted On:11/09/2009
Pages:176-182
Action: [Full Paper] No. of Downloads: 8
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