Статьи журнала - International Journal of Wireless and Microwave Technologies
Все статьи: 454
Design and Implementation of Anti-phishing Authentication System
Статья научная
For phishing problems and its essential characteristics, the authentication protocol of anti-phishing based on two-direction, two-factor, and interaction is proposed, and its safeties are investigated. For PKI security infrastructure and B/S technology model under Internet, an interactive authentication mechanism based on special custom image and client program is designed and implemented. The method is universal to authenticate any server on Internet. It is a new solution of anti-phishing.
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Design and Implementation of Management Information System of Field and Track Training
Статья научная
In terms of features of field and track athletes’ training, this paper, integrating techniques of network, database, computers, multi-media, image processing, etc, devises a management information system of field and track training based on B/S model and provides an training information processing system. This paper analyzes the systematic functional structure and the constitution of systematic sub-systems in detail. Meanwhile, it elaborates on the design of systematic functional structure, network structure, link modes and systematic soft wares’ functions, and introduces web, database and ASP dynamic homepage technique applied in the interactive Web system design, followed by the cases for illustration of some relevant designs.
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Design and Investigation of Circularly Polarized RMPA with Chiral Metamaterial Cover
Статья научная
In this paper, a simple method for designing a circular polarized antenna using chiral metamaterial is presented. The antenna proposed in this paper consists of conventional linear polarized Rectangular Microstrip Patch Antenna (RMPA) and cover of bilayer twisted cross wire Chiral Metamaterial (CM). The placement of CM cover over the linearly polarized RMPA changes its polarization from linear to circular and the antenna produces a left handed circularly polarized wave at resonant frequency of 6.24GHz with axial ratio of 0.46 dB. Investigation of performance parameter of proposed antenna and parameters of unit cell of CM is also presented in the paper.
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Статья научная
This paper is concentrated on comparison of rectangular patch antenna with different ground plane dimensions i.e. short edge, double ground, triple ground in terms of Bandwidth, Gain, Directivity, VSWR, Reflection coefficient and efficiency performance. The finite ground plane gives rise to diffraction of radiation from the edges of ground plane resulting in modifying of radiation conductance, radiation pattern, and resonant frequency. The substrate used is Flame Retardant-4epoxy having dielectric constant of 4.4 and dielectric tangent loss of 0.02. The patch antenna is provided by inset feed line. The design was optimized to obtain the most suitable configuration in terms of desired values of reflection coefficient, bandwidth and Voltage Standing Wave Ratio (VSWR) for antenna with and without modifying on ground plane. These antennas are suitable for WLAN Applications. In this observation, the paper calls for an attention that, the cachet is an amelioration of the 2.4 GHz Industrial, Scientific and Medical (ISM) Band patch antenna is simulated and analysed using HFSS 13.0 and fabricated by photo lithography. The proposed antenna is tested using VNA E5071C.As a result it can be also observed in being when the size of ground plane is increased, the ripples in the main pattern diminishes.
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Design and Simulation Implementation of an Improved PPM Approach
Статья научная
Different from recent probabilistic packet marking (PPM) methods, Dynamic PPM may solve many problems of traditional methods, such as loss of marking information, hard to reconstruct attack path, low accuracy, and so on. A novel DPPM approach is proposed and the network simulation software (NS2) is used to verify the performance and efficiency of the approach by constructing simulation DOS environments. In comparison with PPM methods, simulation results show that DPPM is much better.
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Design and measurement of novel shaped microstrip antenna with DGS for radar applications
Статья научная
In this paper, a novel shaped patch antenna for triple band frequency of operation in X-band (radar) is defined. The antenna resonates under three frequency bands at 10 GHz, 10.93 GHz and 11.68 GHz respectively which are included in the X-band frequency range. The substrate material used as the dielectric between the patch and the ground is of Flame Retardant Version 4 (FR4) Epoxy. The DGS (Defected Ground Structure), usually included in the back conductor of the Microstrip patch antenna is used to tune the frequency and also to boost the characteristics of the antenna. The same is included in this depicted antenna with circular ring shaped slot to vary the performance. FEM (Finite Element Method) based Ansoft High Frequency Structural Simulator (HFSS) V.12 is used for designing and verifying the features of the proposed antenna. The size of the depicted model on the whole is of 31.34 × 28.33 × 1.6 mm3. For the first, second and third resonant frequency, a bandwidth of 480 MHz, 600 MHz and 420 MHz correspondingly is obtained with a return loss value of -18.47 dB, -42.22 dB and -19.74 dB. The other parameters of the antenna are also conferred in this paper.
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Design and performance analysis of a triple band micro-strip patch antenna with CPW-fed
Статья научная
A compact microstrip patch antenna (RMPA) using systematic coplanar waveguide (CPW-Fed) triple printed antenna has designed for WiMAX/WLAN applications in this paper. A prototype CPW-Fed antenna was fabricated with FR4 Substrate with the dielectric constant of 4.4 and thickness h =1.6 mm. The antenna primarily consists of the symmetrical coplanar waveguide with rectangular slotted patch and excite by a 50 Ω CPW feed line for impedance matching to generate wide triple operating bands. This antenna is suitable for the range from 2.39 -2.75 GHz, 3.4-3.7GHz and 4.6 -6.9 GHz. It is designed miniaturized CPW-Fed microstrip patch antenna has a compact size 20 mm x 35 mm. In this paper researcher has focused on to improve the gain, impedance bandwidth and also have lower return losses, better impedance matching. The simulated results show that the proposed antenna has achieved wider bandwidth with satisfactory gain by introducing a stub with CPW-Fed in the assistant of a rectangular slot in the upper layer.
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Design of Adder Using Quantum Cellular Automata
Статья научная
QCA is the trending technologies for designing less hardware and low power consumed circuits measured in Nano-scale. These QCA cells are accustomed to construct combinational and sequential circuits. In this paper we presented a design for developing a basic arithmetic unit called full adder using Quantum cellular automata. The new submitted FA consists fewer amounts of quantum cells and delay also minimizes, when compared with the existing architecture.
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Design of Dual-band SIW Cavity Backed Slot Antenna for X-band Applications
Статья научная
In this article, a novel design for the bandwidth improvement of a substrate integrated waveguide (SIW) cavity-backed slot antenna (CBSA) is presented. The introduced structure utilizes an inverted L-shaped slot and unbalanced metalized vias. The proposed antenna is of low height and holds a planar geometry while sustaining lower losses and lightweight. The inverted L-shaped slot at the bottom plate is responsible for radiation. The quality factor of the SIW cavity is significantly reduced by the inverted L-shaped slot which leads to attaining a wideband response. The proposed antenna resonates at two frequencies 9.4025 GHz and 10.0075 GHz in the first band from the range 9.27 GHz to 10.13 GHz with the fractional bandwidth of 8.915% and at 12.07 GHz in the second band from the range 11.96 GHz to 12.2 GHz with fractional bandwidth of 1.9%.
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Статья научная
A microstrip trapezoidal patch antenna structure has been proposed to serve different space applications including the fixed satellite applications, mobile and radiolocation services. This structure utilizes a 0.787 mm thick RT Duroid (5880) substrate of relative permittivity 2.2 and a dielectric loss tangent of 0.0009. A trapezium shaped patch has been formed on it. The patch is compact and has a novel geometry. The feeding technique employed is coaxial/probe feed. The parametric analysis done over HFSS-15 software to study the effects of the structural design over the behavior of antenna reveals the potentiality of the designed antenna to maintain a nearly constant gain upon the variation of several parameters individually. The use of parallel slots in the design offer a reduction in the size of the patch [5]. The performance of the antenna has been analyzed in terms of reflection coefficient, bandwidth and radiation pattern. The antenna yielded a simulated single band reflection coefficient of -22.5 dB and a peak gain of 4.7 dBi at 3.64 GHz and an impedance bandwidth of 10 MHz at -10 dB reflection coefficient. The fabricated design was tested over VNA for its reflection coefficient. The measured results have been included.
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Design of Microwave Antenna for Hyperthermia System
Статья научная
Hyperthermia is a thermal therapy for cancer treatment in which body temperature is exposed to elevated temperature of 40-42oC. Microwave ablation has a potential to be sensitive to changes in the dielectric tissue parameters which results in damaging abnormal tissues. In order to produce heat in the focused area microwave signals are adjusted in time, frequency and strength. The commonly used frequencies in microwave imaging systems are 415MHZ and 2.45GHZ which are transmitted from the antennas enclosing the relevant body part. This paper presents a highly efficient E-Shape micro strip patch microwave antenna operated at 2.45 GHz which can be used in various applicators for hyperthermia treatment system. The simulation is done on IE3D simulator. The results are compared at two feeding points 1 and 2 for the frequency 2.45GHZ. It gives return loss of -19.3dB, bandwidth of 6.2dB and the antenna efficiency of 92% for feeding point 1 which proves to be highly effective in communication.
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Design of Microwave Pyramidal Absorber for Semi Anechoic Chamber in 1 GHz~20 GHz range
Статья научная
In this paper, the design and development of wideband microwave pyramidal absorbers for semi anechoic chambers has been presented. This work is carried out with the goal of simulating and fabricating the microwave absorber using conventional and newest material such as polyurethane to save the budget cost with security and reliability. The simulation of absorber is performed via Computer Simulation Technology (CST) for the microwave frequencies 1 GHz to 20 GHz. The outcomes of simulation proved good absorbing efficiency and better RCS reduction compared to traditional microwave absorber. The reflection level is less than -30 to -10 dB over the desired frequency range of 1 GHz ~ 20 GHz.
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Design of NAND FLASH File System Based on Loss of Balance Algorithm
Статья научная
NAND FLASH is a commonly large capacity memory, which used in embedded systems .It often used to store the operating system kernel and file system. NAND FLASH memory has a limited number of block erase feature. Built file system in NAND FLASH, loss of balance method should be adopted. A balanced system of block erase operation, can extend the life of NAND FLASH and improve overall system reliability. The paper analyzes the characteristics of NAND FLASH work .presents a loss of balance algorithm which used in NAND FLASH memory , and given out the implementation of the algorithm design method.
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Design of Smart Antenna by Circular Pin-Fed Linearly Polarized Patch Antenna
Статья научная
For the transmission of signals at higher frequencies, there is a requirement for extension of a higher capacity system and higher bandwidth in wireless communication systems. The use of smart antenna increases the system performance with the arrangements of its constituent elements and digital signal processing capacity. Analysis and design of smart antenna arrays can be performed for wireless communication systems using various methods and approaches. One of these methods is circular pin-fed linearly polarized patch antenna has been adopted in this research work. This work presents the design and analysis of smart antenna by circular pin-fed linearly polarized patch antenna. Patch antenna is a very prominent antenna in the microwave frequency spectrum due to its simplicity and compatibility with the printed circuit board (PCB) technology.
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Design of a Compact Fractal Unit Cell Absorber for the 2.45 GHz Band
Статья научная
This paper presents the design of a fractal unit cell absorber for electromagnetic energy absorption in the 2.45 GHz band. The configuration is based on a second-order Minkowski-inspired fractal geometry, through which a compact structure is realized. The proposed design is achieved using full-wave electromagnetic simulations and the study of an equivalent circuit model. At 2.45 GHz, the synthesized structure achieves a near-perfect absorptivity of 99%, with a modest footprint of 0.11λ. The realized structure can serve as a constituent element for the design of absorber arrays to mitigate multipath effects and prevent eavesdropping attacks in indoor wireless environments.
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Design of a Virtual Area Network for National Open University Sokoto Study Center
Статья научная
Nowadays, there is a need for an efficient and effective way in which computers are interconnected. In National Open University Sokoto Study Center network there exist problems such as: more traffic which may slower the network performance, bandwidth wastage and security problems because the host and servers that are connected to Layer 2 switch are part of the same network segment. To resolve these problems we identify the networking media that best suits the network to enable person-to-person communication, determine the best network architecture that would enable effective resource sharing between all staff offices, design respective VLANs for different units, configure network addresses for each units and identify configurations required on router and switches to create VLAN’s and Inter VLANrouting. After the implementation of proposed Virtual Local Area Network in ICT unit of National Open University Sokoto study center, effective resource sharing and communication is achieved. Hence, implementation of this study is practically cost effective.
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Design of an UWB bandpass filter using dual MMR with highly attenuated upper stopband using DGS
Статья научная
A miniature sized microstrip UWB (ultra wideband) BPF (bandpass filter) having highly attenuated upper stop band performance using a dual MMR (multimode resonator) and the DGS (defected ground structure) is proposed. Combining these two topologies, a prototype of the proposed UWB BPF is fabricated using FR-4 substrate of 1.6 mm thickness with dielectric constant of 4.4. This BPF is modelled and simulated using Ansoft high frequency structure simulator (HFSS) Software. The simulated and measured results show a wide FBW (fractional bandwidth) of 119% .The insertion loss is less than -1.0 dB throughout the pass band of 2.78 to 10.95 GHz. All the ripples of return loss are lower than -14 dB in the passband. The BPF has a high rejection of more than -30 dB in the upper stop band up to 16.8 GHz. The simulated and measured group delays variation in the passband are found to be less than 0.2 ns. The overall length of the resonator is 7 mm.
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Design of effective security architecture for mobile cloud computing to prevent DDoS attacks
Статья научная
A DOS (Denial of Service) attack, as its name suggests, denies or blocks access to certain services by flooding either the bandwidth of a specified network or by targeting its connectivity. There are much security challenges in mobile cloud computing. Cloud indicates a period of the computing where the services, which are an application, are made available by the internet. Cloud based computing is very adjustable and cheap as to providing a platform for various IT services. The mobile systems can hinge on the cloud based computing with mobile agents and can undertake various processes such as the searching or storing, etc. While it’s very economic, it has many challenges such as the security. Various researches have been carried out to build a secure mobile cloud based computing. In this paper, we have viewed and analyzed the DDOS (Distributed Denial of Service) attacks in depth to prevent it in the mobile cloud computing.
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Design on open-loop bandpass filter with multiple harmonics suppression
Статья научная
In this paper, a simple method based on coupling control theory to suppress multiple harmonics in open-loop bandpass filters is proposed. Coupled feeding is utilizing in this paper, and by choosing proper coupling length and position of the input/output port, multiple harmonics could be suppressed. The input impedance of microstrip line with its end open-circuited is firstly showed and the theory on harmonics suppression is then analyzed to choose a proper coupling position. A second-order open-loop bandpass filter is designed and manufactured, measured and manufactured results both have a stopband to 5f0 with rejection more than 20dB. On the base of the filter proposed, the stopband can be broaden to 10f0 by adding two stubs. It well validates the proposed solution.
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Design truncated rectangular patch microstrip antenna for telecommunication base stations
Статья научная
In this paper a truncated rectangular patch microstrip antenna with multiple slots has been proposed, to provide a wide impedance bandwidth, in addition to acceptable antenna performance parameters such as (gain and radiation pattern). FR-4 substrate is used to design the antenna structure, the substrate has thickness of 1.6 mm and relative permittivity of 4.3. By utilizing CST Microwave Studio Simulation softwer, the simulation procedure has been done. This antenna covers broadband from (0.94GHz to 3.4GHz), therefor it is suitable for operation in telecommunication base stations, and the antenna covers the GSM900, GSM1800, GSM1900, and IMT applications.
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