This PDF file contains the front matter associated with SPIE Proceedings Volume 8760, including the Title Page, Copyright information, Table of Contents, Introduction, and Conference Committee listing.

In this paper, we present a quantitative comparison of two agile modulation techniques employed by cognitive radio transceivers operating in a dynamic spectrum access (DSA) network. One of the modulation techniques is single carrier frequency division multiple access (SC-FDMA). The other modulation technique under study is a variant of multicarrier code division multiple access (MCCDMA). Although several studies comparing conventional OFDM and MC-CDMA has been conducted in literature to justify robust error performance of MC-CDMA, a quantitative performance evaluation of these schemes has not been performed when employed in a DSA network. In this paper we show that their performances can be significantly different from the conventional setup. Analytical expressions for the error probability of an SC-FDMA transceiver have been derived and compared with computer simulation results. The results show that the error robustness of SC-FDMA is relatively better then MC-CDMA in underlay communication.

A compact (40 mm x 35 mm) coplanar waveguide (CPW) fed slot antenna for circular polarization is presented in this paper. The antenna is designed and fabricated for applications in the ultra-wideband domain of wireless communications where circular polarization is also required. The axial ratio (AR) bandwidth of the proposed antenna is 35.46% (5.8 GHz– 8.3 GHz), while the experimental impedance bandwidth is from 2.8 GHz – 8.6 GHz. The experimental results are very close to the simulated results. The antenna displays a stable radiation pattern and a moderately high gain of around 5 – 6 dB in the useful band.

Expanded graphite/novolac phenolic resin (EG/NPR) composites are developed as dielectric absorbers with 4mm thickness and its microwave absorption ability studied in the frequency range 8.4 to 12.4 GHz. A high reflection loss ~ -43 dB is observed at 12.4 GHz for 5 wt. % EG/NPR composites. With the increase in EG concentration in the composite the reflection loss decreases and the absorption peak shifts towards lower frequency. 7 wt. %, 8 wt. % and 10 wt. % composites shows a 10dB absorption bandwidth of order of 1GHz. Light weight EG/NPR composite shows potential to be used as cost-effective broadband microwave absorber over the X-band.

In this paper a new way of feeding single layer microstrip patch antenna using electromagnetically coupled microstrip junction is proposed with good isolation between the two ports. The proposed antenna eliminates the need for capacitors in the path for active antenna applications in WLAN. The simulated results using IE3D software were verified by measurement using the vector network analyzer.

Fabrication and electrical characterization of a Pd/TiO₂/n-Si MIS structure have been reported in this paper. The TiO₂ layer has been deposited on n-Si by using low temperature arc vapor deposition (LTAVD) technique. The currentvoltage and capacitance-voltage characteristics were studied at room temperature (300 K) for sample devices with TiO₂ film annealed at different temperatures (450 to 550°C). The study reveals that the capacitance in the accumulation region has frequency dispersion at high frequencies which is attributed to leakage behavior of TiO₂ insulating layer, interface states and oxide defects. As-deposited film exhibits high level of interface states resulting in high leakage current density which can be reduced by an order of magnitude by post-deposition annealing. Different models of current conduction mechanism have been applied to study the measured data. It is found that Schottky–Richardson (SR) emission model is applicable at low bias voltage, Frenkel-Poole (FP) emission model at moderate bias voltages while Fowler–Nordheim (FN) tunneling dominates at higher bias voltages.

This paper describes the comparative study of Artificial Neural Network (ANN) and Support Vector Machine (SVM) classifiers by taking a case study of identification and classification of four pairs of similar looking food grains namely, Finger Millet, Mustard, Soyabean, Pigeon Pea, Aniseed, Cumin-seeds, Split Greengram and Split Blackgram. Algorithms are developed to acquire and process color images of these grains samples. The developed algorithms are used to extract 18 colors-Hue Saturation Value (HSV), and 42 wavelet based texture features. Back Propagation Neural Network (BPNN)-based classifier is designed using three feature sets namely color – HSV, wavelet-texture and their combined model. SVM model for color- HSV model is designed for the same set of samples. The classification accuracies ranging from 93% to 96% for color-HSV, ranging from 78% to 94% for wavelet texture model and from 92% to 97% for combined model are obtained for ANN based models. The classification accuracy ranging from 80% to 90% is obtained for color-HSV based SVM model. Training time required for the SVM based model is substantially lesser than ANN for the same set of images.

This paper presents the design and optimization of microstrip cross coupler, starting from the concept of 90° hybrid, that can operate in two frequency bands. Large power division ratio is achieved in the dual band by enhancing the length of the conventional 0 dB coupler (cross-coupler). The proposed circuit also features compact size and planar structure. Microstrip cross- coupler operating in the two frequency bands (1.28 to 1.695 GHz and 2.71 to 3.305 GHz) with corresssponding minimum return loss frequencies of 1.6 GHz and 2.9 GHz is designed through circuit theory approach and optimized using Ansoft HFSS software. The power division ratios obtained at 1.6 GHz and 2.9 GHz are 16.38 dB and 15.79 db respectively. In integrated circuit, considering h ≤ 0.01λ (h=substrate height) so that step discontinuity reactance becomes negligible, no compensation technique is required. The same quadrature phase relationship is obtained between the input and coupled signals at the two operating frequencies.

In this paper an all-optical exclusive OR (XOR) gate is proposed, which uses an integrated semiconductor optical-amplifier based Mach-Zehender interferometer. The design works on differential phase modulation scheme and the operation of the proposed gate is verified up to 120 Gb/s. Results of the gate has been analyzed in time domain for different input bit sequences. Highest extinction ratio of 26.01 dB is noted at 80 Gb/s. Rate analysis is also performed to optimize the Quality factor and a bit error rate.

There exist two fundamental approaches to multicast routing namely minimum cost trees and shortest path trees. The (MCT’s) minimum cost tree is one which connects receiver and sources by providing a minimum number of transmissions (MNTs) the MNTs approach is generally used for energy constraint sensor and mobile ad hoc networks. In this paper we have considered node mobility and try to find out simulation based comparison of the (SPT’s) shortest path tree, (MST’s) minimum steiner trees and minimum number of transmission trees in wireless mesh networks by using the performance metrics like as an end to end delay, average jitter, throughput and packet delivery ratio, average unicast packet delivery ratio, etc. We have also evaluated multicast performance in the small and large wireless mesh networks. In case of multicast performance in the small networks we have found that when the traffic load is moderate or high the SPTs outperform the MSTs and MNTs in all cases. The SPTs have lowest end to end delay and average jitter in almost all cases. In case of multicast performance in the large network we have seen that the MSTs provide minimum total edge cost and minimum number of transmissions. We have also found that the one drawback of SPTs, when the group size is large and rate of multicast sending is high SPTs causes more packet losses to other flows as MCTs.

A Novel Design using two feed structure for Ultra Wide Band Antenna with band notch characteristics is being presented in this paper. The simulated antenna so designed have a compact small physical size of 16 mm (L) × 20 mm (W) × 1.6 mm (h) of the overall design with the patch size as 11.86 mm (L) × 8.96 mm (W). The antenna is designed to simulate at 10 GHz. The substrate used is Duroid™ with a relative permittivity of (εr=2.2) and the return loss so measured is calculated below -10 dB for the range 3.1-19.53 GHz with band notching in the frequency band 5.1-5.8 GHz (i.e. WLAN). To achieve such UWB antenna with band notch, the three concepts used are introduced, the first one is using two feeding structure, the second one is using steps at the bottom of the patch, introducing steps at the bottom centre of the patch for band notching. The final impedance bandwidth so measured is 145 % which is a very high bandwidth so obtained. The optimized antenna designed can be used in any of the wireless device for UWB applications.

A method to design microstrip low pass filter having defected ground structure (DGS) is proposed. The difference between standard asymmetric microstrip technique and DGS is in using the structures etched in the microwave substrate ground plane. The DGS resonant characteristics are then used in filter design. The equivalent circuit for the proposed defected ground unit structure is derived by means of three-dimensional field analysis methods. The equivalent-circuit parameters are extracted by using a simple circuit analysis method. Filters of various orders and resonator configurations are designed and simulated. A combination of the DGS and five order low pass Chebyshev microstrip filter is designed as well realized and measurement results are compared with simulations. The experimental results show excellent agreements with theoretical results and the validity of the modeling method for the proposed defected ground unit structure. Finally, enhanced cut off frequency 2.715GHz of microstrip low pass chebyshev filter using DGS is observed.

Main disadvantage of a multicarrier communication system is high peak to average power ratio (PAPR) of the transmitted signal. The high PAPR causes the performance degradation due to nonlinear distortion in the high power amplifier (HPA). PAPR value is closely depends on transmitted power and correlation properties of the user’s spreading code. High peak and low average value of the transmitted power increases the PAPR. On the other side high auto correlation function (ACF) value and low cross correlation function (CCF) value of the spreading code also increases the PAPR. But to eliminate the multiple access interference (MAI) in receiver end, ACF should be peak and CCF should be posses zero for all time shifts. So, there is a conflicting nature of PAPR and bit error rate (BER). That’s why an exhaustive effort has been made in this paper for proper distribution of transmitted power within an acceptable range of peak transmitted power and evaluates the new spreading codes using Genetic Algorithms (GA). In general, to obtain optimum PAPR reduction using GA, total searching time to find out the proper amplitude and phase parameters must be accomplished. Simulation results show that PAPR and BER performance using this proposed technique is better than conventional network.

The Zinc oxide (ZnO) nanoparticles have been grown on n type silicon substrate using tin (Sn) metal as seed layer by a low cost thermal evaporation method. SEM images show that the ZnO nanoparticles have been uniformely grown on the whole substrate surface relatively perpendicular to the substrate. The Photoluminescence (PL) spectrum consists of strong UV emission at wavelength of 355 nm along with a broad near band edge (NBE) emission covering a wide range of wavelength from 370 to 550 nm. This broadening region exhibits blue, violet and green emission due to the presence of native defects such as zinc interstitial (Zn_i), oxygen vacancy (V_O) and oxygen interstitial (O_i) in the band gap of ZnO. Raman spectroscopy shows the existence of E₂ mode at 437 cm^-1 which confirms the pure wurtzite hexagonal phase of ZnO. The optical and structural properties of ZnO nanoparticles could be explored for blue-violet light emitting diodes (LEDs) and gas sensing applications.

In this paper Sierpinski E-Carpet antenna based on the implementation of fractal technique is proposed for multiband applications in 2-10 GHz band. There appeared 5 resonant frequencies at 2.35 GHz, 3.5 GHz, 5.503 GHz, 7.248GHz, and 8.79GHz for 2nd iteration. From the return loss plot it is seen that antenna achieved the IEEE Bluetooth/WLAN (2.4-2.484 GHz), WiMAX (3.4-3.69 GHz) and WIFI (5.1-5.825 GHz) frequency band with -10dB return loss. Also nearly omni-directional radiation pattern is observed. A prototype of the design is successfully implemented with close agreement between measurement and simulation result.

In this work the quasi-static spectral domain approach (SDA) applicable to a lossy multilayer CPW that incorporates two-layer model of a conductor thickness and the concept of effective permeability due to magnetic field penetration in an imperfect conductor is used to account low frequency dispersion analysis. The accuracy of formulation is comparable to that of HFSS and CST, without using complex and time consuming full-wave methods. The results of CST for epsilonƐ_eff , Z_o of multilayer CPW, in the frequency range 100 MHz – 10 GHz, deviate from results of HFSS up to 1.34% and 2.37% respectively; whereas corresponding deviations of present formulation are 4.15% and 2.22%.

In this paper, we present feeding approaches of coplanar waveguide fed (CPW) circular microstrip patch antennas, with and without defected ground structure (DGS)`. The antenna feeding impedance is proposed as 50 ohms, built over FR4, a high dielectric constant substrate to obtain broad impedance bandwidth along with stability of the radiation patterns. The antenna with defected ground structure is designed to have band-notched characteristics at 3.5 GHz (for Wi-MAX band-3.3 to 3.7 GHz), at 8.2 GHz (for ITU band-8.025 GHz to 8.4 GHz) so as to avoid interference from these. The FR4 is used as dielectric with value of dielectric loss tangent constant as 0.002 and relative permittivity with 4.4. After applying DGS in ground of the proposed antenna there were improvements concerning bandwidth, and also a small increase in gain was noticed. These antennas are of small sizes with dimensions; 30 mm X 43 mm X 1.6 mm, cheap, compact and easy to fabricate, and achieve good radiation characteristics with higher return loss. This first antenna can have wide application in a great variety of wireless communication and second can operate well as UWB antenna with band notched characteristics. The performance of two antennas is compared in respect to gain, VSWR, return loss and impedance matching.

In the present investigation, microwave absorption properties of a conductor back single layer designed on graphite flakes (GF)-novolac phenolic resin (NPR) composites is studied. The complex permittivity of the developed composite enhance for higher GF percentages. The reflection loss(RL) measured using E8362C VNA shows a maximum RL values -25 dB at 9.8 GHz for 7 wt. % composition with -10 dB bandwidth of 0.3 GHz. The developed composites are being light weight and cost effective shows potential to be used as dielectric absorber.

An E-shape patch antenna is designed and demonstrated their effectiveness using Particle Swarm Optimization (PSO), which is used for wireless applications. The concept of PSO is briefly introduced in the design procedure and the design parameters are explained. This work focuses on identifying the increasing popularity of swarm intelligence specifically among the electromagnetic community. It is implemented using PSO combined with numerical algorithms for electromagnetic solutions, such as the Finite Element Method (FEM) and the Method of Moments (MOM). In both the realizations, the PSO technique drives the design variables such as antenna dimensions and geometrical features. The fitness function is evaluated for the optimizer. This is achieved by using CAD FEKO 6.1, electromagnetic simulation software. The model is designed with a resonant frequency of 2.65GHz.

Wireless Sensor Networks (WSNs) are networks of sensor nodes deployed over a geographical area to perform a specific task. WSNs pose many design challenges. Energy conservation is one such design issue. In literature a wide range of solutions addressing this issue have been proposed. Generally WSNs are densely deployed. Thus the nodes with the close proximity are more likely to have the same data. Transmission of such non-aggregated data may lead to an inefficient energy management. Hence the data fusion has to be performed at the nodes so as to combine the edundant information into a single data unit. Distributed Source Coding is an efficient approach in achieving this task. In this paper an attempt has been made in modeling such a system. Various energy efficient codes were considered for the analysis. System performance in terms of energy efficiency has been made.

Free Space Optical (FSO) technology offers highly directional, high bandwidth communication channels. This technology can provide fiber-like data rate over short distances. In order to improve security associated with data transmission in FSO networks, a secure communication method based on chaotic technique is presented. In this paper, we have turned our focus on a specific class of piece wise linear one-dimensional chaotic maps. Simulation results indicate that this approach has the advantage of possessing excellent correlation property. In this paper we examine the security vulnerabilities of single FSO links and propose a solution to this problem by implementing the chaotic signal generator “reconfigurable tent map”. As synchronization between transmitter and receiver is essential for the correct operation of such schemes, we have also attempted to determine parameters such as auto- and cross-correlation that determine the ease with which synchronization between transmitter and receiver can be achieved. It is demonstrated that cross correlation is very close to zero and auto-correlation is 􀟜-like. The overall system is implemented in the MATLAB Simulink DSP Builder.

Design of an intelligent level measurement technique by Capacitance Level Sensor (CLS) using an Optimized Artificial Neural Network (OANN) is discussed in this paper. The objectives of the present work are (i) to extend the linearity range of measurement to 100% of the full scale, (ii) to make the measurement technique adaptive of variation in permittivity of liquid, liquid temperature, and to achieve objectives (i) and (ii) using an optimized neural network. An optimized ANN is considered by comparing various algorithms, transfer functions of neuron, and number of hidden layers based on minimum mean square error (MSE). The output of CLS is capacitance. A data conversion unit is used to convert it to voltage. A suitable optimized ANN is added, in place of conventional calibration circuit, in cascade to data conversion unit. The proposed technique provides linear relationship of the overall system over the full input range and makes it adaptive of variation in liquid permittivity and/or temperature. When an unknown level is tested with an arbitrary liquid permittivity, and temperature, the proposed technique has measured the level correctly. Results show that the proposed scheme has fulfilled the objectives.

Nanosized barium ferrite (BaFe₁₂O₁₉) powders are synthesized using co-precipitation technique at three different annealing temperatures. The X-Ray Diffraction pattern indicates the presence of hexagonal structure for all the three samples. Transmission electron microscopy (TEM) shows the particles are hexagonal in shape. The synthesized BaFe₁₂O₁₉ powder samples are mechanically mixed with Novolac phenolic resin (NPR) with filler to polymer weight ratio of 30:60 to prepare pellets of BaFe₁₂O₁₉/NPR composites of dimensions, 10.38 mm x 22.94 mm x 4 mm. The complex permittivity, ε_r and complex permeability, μ_r of the developed samples are measured at X-band by Nicolson-Ross method using Agilent E8362C vector network analyzer. The effect of the annealing temperature on the complex permittivity and permeability in the X-band is studied. The maximum dielectric constant and permeability is obtained of the BaFe₁₂O₁₉/NPR composite with BaFe₁₂O₁₉ annealed at 900⁰C as 6 and 2 respectively. The composite is a good candidate for microwave absorption study.

The class of nonlinear phenomena based on photorefractive effect in electro-optical crystals plays a vital role in improving the parameters of high power lasers diodes. In optimisation of high power laser diodes both experimental and numerical analysis are very important. The main advantage of numerical modelling is its usefulness to optimisation of device performance in order to meet the target specification. Numerical model allows to simulate scenarios in advance and provides solutions before the investment decisions are made. Moreover, the numerical modelling of photorefractive crystals allows to understand the device characteristics. The main aim of the work was the development of the numerical model for adaptive Fabry-Perot filter using a photorefractive crystal. There were two particular objectives to be reached within this project. The first one was to develop a software tool which allows for calculating the optical field distribution within an optical grating. The second one consisted in combining the developed grating model with an advanced model of the photorefractive crystal based on the solution of Kukhtarev equations. Both objectives have been achieved.

The growing interest in the use of chaotic techniques for enabling secure communication in recent years has been motivated by the emergence of a number of wireless services which require the service provider to provide low bit error rates (BER) along with information security. This paper investigates the feasibility of using chaotic communications over Multiple-Input-Multiple-Output (MIMO) channels. While the use of Chaotic maps can enhance security, it is seen that the overall BER performance gets degraded when compared to conventional communication schemes. In order to overcome this limitation, we have proposed the use of a combination of Chaotic modulation and Alamouti Space Time Block Code. The performance of Chaos Shift Keying (CSK) with 2×1 and 2×2 Alamouti schemes for different chaotic maps over wireless channels has been studied. It has been shown that the use of these schemes can provide security enhancement without the penalty of degradation of BER performance.

Artificial Neural Network (ANN) has been applied in statistical model development, adaptive control system, pattern recognition in data mining, and decision making under uncertainty. The nonlinear dependence of any sensor output on the input physical variable has been the motivation for many researchers to attempt unconventional modeling techniques such as neural networks and other machine learning approaches. Artificial neural network (ANN) is a computational tool inspired by the network of neurons in biological nervous system. It is a network consisting of arrays of artificial neurons linked together with different weights of connection. The states of the neurons as well as the weights of connections among them evolve according to certain learning rules.. In the present work we focus on the category of sensors which respond to electrical property changes such as impedance or capacitance. Recently, sensor materials have been embedded in etched tracks due to their nanometric dimensions and high aspect ratio which give high surface area available for exposure to sensing material. Various materials can be used for this purpose to probe physical (light intensity, temperature etc.), chemical (humidity, ammonia gas, alcohol etc.) or biological (germs, hormones etc.) parameters. The present work involves the application of TEMPOS structures as humidity sensors. The sample to be studied was prepared using the polymer electrolyte (PEO/NH4ClO4) with CdS nano-particles dispersed in the polymer electrolyte. In the present research we have attempted to correlate the combined effects of voltage and frequency on impedance of humidity sensors using a neural network model and results have indicated that the mean absolute error of the ANN Model for the training data was 3.95% while for the validation data it was 4.65%. The corresponding values for the LR model were 8.28% and 8.35% respectively. It was also demonstrated the percentage improvement of the ANN Model with respect to the linear regression model. This demonstrates the suitability of neural networks to perform such modeling.

Quality of Service (QoS) features shall provide the required performance of latency, jitter and packet loss needed to support the service. QoS and mobility management are two major issues to keep providing the same level of quality to the packet flow during and after a handover. In this paper we have analysed two schemes for handover taking QoS parameters into consideration such as jitter, packets delivered, throughput number of handovers. We have observed improvement QoS parameters, from user point of view with mobility for different types services.

In this paper, we propose a Simulation for the test of SNDR (Signal to noise and Distortion ratio) in Sigma Delta ADC for SDR 3G and 4G mobile Receivers. Now a days, SNDR is one of the most important parameter which directly effects the performance of ADC. Simulation results show the Capability of the simulink to obtain SNDR for a 8 bit and 10 bit audio Sigma delta ADC. SNDR of ADC will always be less than SNR. The simulation model of second order Sigma Delta ADC is given in the paper. The SNR and SNDR have been taken into account.

In all walks of life the way of communication is transformed by the rapid growth of wireless communication and its pervasive use. A wireless network which is fixed and richer in bandwidth is specified as IEEE 802.16, promoted and launched by an industrial forum is termed as Worldwide Interoperability for Microwave Access (WiMAX). This technology enables seamless delivery of wireless broadband service for fixed and/or mobile users. The obscurity is the long delay which occurs during the handoff management in every network. Mobile WiMAX employs an authenticated key management protocol as a part of handoff management in which the Base Station (BS) controls the distribution of keying material to the Mobile Station (MS). The protocol employed is Privacy Key Management Version 2- Extensible Authentication Protocol (PKMV2-EAP) which is responsible for the normal and periodical authorization of MSs, reauthorization as well as key refreshing. Authorization key (AK) and Traffic Encryption key (TEK) plays a vital role in key exchange. When the lifetime of key expires, MS has to request for a new key to BS which in turn leads to repetition of authorization, authentication as well as key exchange. To avoid service interruption during reauthorization , two active keys are transmitted at the same time by BS to MS. The consequences of existing work are hefty amount of bandwidth utilization, time consumption and large storage. It is also endured by Man in the Middle attack and Impersonation due to lack of security in key exchange. This paper designs an automatic mutual refreshing of keys to minimize bandwidth utilization, key storage and time consumption by proposing Previous key and Iteration based Key Refreshing Function (PKIBKRF). By integrating PKIBKRF in key generation, the simulation results indicate that 21.8% of the bandwidth and storage of keys are reduced and PKMV2 mutual authentication time is reduced by 66.67%. The proposed work is simulated with Qualnet model and backed by MATLAB for processing and MYSQL for storing keys.

Long-period waveguide gratings (LPWGs), by using a SU-8 polymer-based channel waveguide along with NOA61 optical epoxy coated upper- and lower-cladding, are designed and theoretical analyzed. Grating period of ~ 68μm is considered with optimized grating tooth-heights, so that the transmission spectra of the gratings show strong rejection bands both at visible (450 – 460 nm) and infrared (1530 – 1540 nm) wavelength regions. Phase-matching graphs are studied in order to observe the change in resonance wavelength of the grating with the variation of waveguide parameters. LPWG-based band pass filter are also designed and analyzed by considering the same set of polymer materials. Further, temperature sensitivity of these LPWGs is analyzed theoretically. These types of waveguide gratingbased filters can widely be used for visible and infrared wavelength sensing applications.

In this paper design of a fiber having ultra-flattened dispersion with small dispersion slope, ultra-large effective area over a wide spectral range has been presented. The segmented core of the fiber helps in achieving large mode field diameter and maintaining very small dispersion over a wide range of wavelengths. The maximum value of dispersion and dispersion slope of the designed fiber is −1.4 ps/km/nm and 0.047 ps/km/nm² respectively within the spectral range of 1460-1666 nm. The proposed fiber has ultrahigh effective area ranging from 116 μm² to 504 μm² in the aforementioned wavelength range, which covers the entire S+C+L-band.

Microstrip patch antenna is fabricated on a magnetodielectric substrate synthesized using 5% volume fraction of nano-sized cobalt ferrite and nickel ferrite inclusions. The permittivity, Εr and permeability μr, of the tailored substrate is determined by in touch superstrate method and cavity perturbation respectively. The S11 parameters are measured in the frequency range from 8 to 11.5 GHz with varying external magnetic field. Unlike antennas made on bulk ferrites, the antennas on these substrates show very low resonant frequency tenability. An enhancement of return loss from -26dB to-31 dB for CoFe₂O₄/LDPE antenna at 9 GHz and -25dB to -32.5 dB for NiFe₂O₄/LDPE antenna at 10GHz is observed.

The current generation of wireless networks has been designed predominantly to support voice and more recently data traffic. WiMAX is currently one of the hottest technologies in wireless. The main motive of the mobile technologies is to provide seamless cost effective mobility. But this is affected by Authentication cost and handover delay since on each handoff the Mobile Station (MS) has to undergo all steps of authentication. Pre-Authentication is used to reduce the handover delay and increase the speed of the Intra-ASN Handover. Proposed Pre-Authentication method is intended to reduce the authentication delay by getting pre authenticated by central authority called Pre Authentication Authority (PAA). MS requests PAA for Pre Authentication Certificate (PAC) before performing handoff. PAA verifies the identity of MS and provides PAC to MS and also to the neighboring target Base Stations (tBSs). MS having time bound PAC can skip the authentication process when recognized by target BS during handoff. It also prevents the DOS (Denial Of Service) attack and Replay attack. It has no wastage of unnecessary key exchange of the resources. The proposed work is simulated by NS2 model and by MATLAB.

In this paper we have presented a modified dispersion model which is applicable from DC to THz frequency range for microstrip line. We have accounted the finite strip thickness in dispersion formula of Kirschning and Jenson. We have compared the results of this model with EM simulator HFSS and the average deviation is within 1%.

A new CMOS current starved voltage controlled ring oscillator (CSVCRO) topology is presented. The proposed voltage controlled oscillator was designed, analyzed and verified by simulating it in 0.35μm CMOS technology. The VCO architecture proposed in this work provides high linear relationship between oscillation frequency ranging from 0.7- 1.75GHz over a control voltage ranging from 1.2--2V and results in a large tuning range of 75%. The phase noise achieved is -88dBc/Hz at an offset frequency of 1MHz. The linear frequency sweep is obtained without employing any additional compensation techniques resulting in less circuit complexity, die area and power consumption.

venient window on the mind, revealing synaptic action that is moderately to strongly co-relate with brain state. Fractal dimension, measure of signal complexity can be used to characterize the physiological conditions of the brain. As the EEG signal is non linear, non stationary and noisy, non linear methods will be suitable for the analysis. In this paper Higuichi’s fractal method is applied to find the fractal dimension. EEGs of 5 volunteers were recorded at rest and on exposure to radiofrequency (RF) emissions from mobile phones having different SAR values. Mobiles were positioned near the ears and then near the cz position. Fractal dimensions for all conditions are calculated using Higuich’s FD estimation algorithm. The result shows that there are some changes in the FD while using mobile phone. The change in FD of the signal varies from person to person. The changes in FD show the variations in EEG signal while using mobile phone, which demonstrate transformation in the activities of brain due to radiation.

The tremendous increase in wireless communication in the last few decades has led to the need of larger bandwidth and low profile antennas for both commercial and military applications. One technique to construct a multiband antenna is by applying fractal shape into antenna geometry. Fractal antennas due to their self similar design take less area and are thus low profile. This paper presents the design and implementation of Sierpinski carpet fractal antenna up to third iteration. The proposed antenna is designed and fabricated on FR4 substrate with dielectric constant of 4.4 and fed with 50 ohms microstrip line. However the gain of the 3rd iteration Sierpinski carpet fractal antenna is small, to increase the gain of the antenna modifications in the fractal geometry have been proposed.

The purpose of this paper is to present the review of certain face recognition techniques. Although the existing methods perform well under certain conditions but illumination, occlusion, pose, structural components, facial expression and quality of images are still the challenging problems. In reviewing these techniques we have compared the performance of various techniques used for face recognition. The performances are compared in order to state advantages and limitations of each technique discussed.

The paper presents an image watermarking algorithm based on Contourlet Transform (CT) and QR factorization method. Contourlet Transform is used to transform both the cover and watermark image into subbands. The watermarking is applied to the Contourlet Transform as the human visual system is comparatively less sensitive to edges of the image. The low frequency coefficients of an image contain the highest energy. Thus the lowest frequency coefficients of the contourlet transformed original and watermark image are selected for watermarking. The selected coefficients are then decomposed using QR factorization method. The QR factorized coefficients of watermark image is embedded into the QR factorized original image values. Inverse QR and inverse CT is then applied on the watermark embedded coefficients of image to obtain the watermarked image. Experimental results show that the proposed algorithm is a better technique as compared to other watermarking schemes based on Contourlet Transform. The proposed watermarking scheme is imperceptible and robust against image processing attacks such as Gaussian noise, scaling, compression, salt and pepper noise.

OFDM technology contains several terminologies, transform algorithms for communication engineering. In this way Companding transforms useful under assumption of infinite bandwidth. Under band limited conditions Out of band radiation (OBR) parameter filters out. So bandwidth is a factor that decides the filtering out OBR on the performance of companded OFDM systems. As a result filtering becomes essential under band limited conditions in turn this does deteriorate the system performance significantly. In this paper method proposed to overcome the performance degradation. Method called non symmetric scheme based on the use of curve fitting method to find out a suitable polynomial to be used for decompanding at the receiver. This method indeed improves the performance in comparison to existing symmetric methods when filtering is necessary for band limited conditions.

Orthogonal Frequency Division Multiplexing (OFDM) is an emerging multi-carrier modulation scheme, which has been adopted for several wireless standards such as IEEE 802.11a and HiperLAN2, etc. A well-known problem of OFDM is its sensitivity to frequency offset between the transmitted and received carrier frequencies. In (OFDM) system Carrier frequency offsets (CFOs) between the transmitter and the receiver destroy the orthogonality between carriers and degrade the system performance significantly. The main problem with frequency offset is that it introduces interference among the multiplicity of carriers in the OFDM signal.The conventional algorithms given by P. Moose and Schmidl describes how carrier frequency offset of an OFDM system can be estimated using training sequences. Simulation results show that the improved carrier frequency offset estimation algorithm which uses a complex training sequence for frequency offset estimation, performs better than conventional P. Moose and Schmidl algorithm, which can effectively improve the frequency estimation accuracy and provides a wide acquisition range for the carrier frequency offset with low complexity. This paper introduces the BER comparisons of different algorithms with the Improved Algorithms for different Real and Complex modulations schemes, considering random carrier offsets . This paper also introduces the BER performances with different CFOs for different Real and Complex modulation schemes for the Improved algorithm.

A dual band double square patch with 2-bridges printed microstrip patch antenna is presented in this paper. The ntenna operates at centre frequencies of 2.4GHz and 9.7GHz which can be used for wireless local area networks and radio navigation or radio location applications in S-band and X-band respectively at low powers. The dual band antenna has good simulated return loss and bidirectional radiation characteristics. The electromagnetic (EM) simulation software is used for the simulation. The antenna is designed on FR-4 substrate with dielectric constant of 4.4 and thickness of 1.6 millimeter(mm). It is fed with 50Ω coaxial feed line and the total size of antenna is 40×40 mm2. The antenna has return loss lower than -10dB, compact structure, ease of designing, and low manufacturing cost. Two square patches are designed to obtain dual band operation. The larger patch resonates at 2.4GHz and the smaller patch resonates at 9.7GHz respectively. This antenna can be used for wireless local area network (WLAN) and radio navigation applications.

Low-dropout (LDO) regulator with modest ripple and improved transient response is implemented in 0.18μm CMOS technology. The proposed regulator for SOC application can achieve high stability for load current from zero to 100mA. This LDO uses process, temperature independent biasing for error amplifier which makes LDO temperature and process independent. The experimental results show the load regulation of 162 μV/mA and line regulation of 0.9 mV/V. The whole LDO chip consumes a quiescent current of 50 μA with an ultra low dropout voltage of 200mV at the maximum output current of 100mA.

In radio receivers, Digital Down Converters (DDC) are used to translate the signal from Intermediate Frequency level to baseband. It also decimates the oversampled signal to a lower sample rate, eliminating the need of a high end digital signal processors. In this paper we have implemented architecture for DDC employing CORDIC algorithm, which down converts an IF signal of 70MHz (3G) to 200 KHz baseband GSM signal, with an SFDR greater than 100dB. The implemented architecture reduces the hardware resource requirements by 15 percent when compared with other architecture available in the literature due to elimination of explicit multipliers and a quadrature phase shifter for mixing.

Image fusion is the process of combining two or more images of the same scene into a single image which is suitable for human perception and practical applications. This paper investigates the effect of use of different types of masks in discrete cosine transform (DCT) domain for image fusion applications. Here we have used different types of masks such as rectangular, triangular, strip and fan shaped mask. In the proposed scheme, the DCT of both the images are taken and mask and its complimentary mask are applied on two transformed images respectively. The masked images are then fused in the transform domain and inverse DCT is applied to obtain the fused image. Simulation results of the proposed technique are also presented and it is observed that fusion based on the fan shaped mask gives better quality of fused image than other masks consider in this paper as well as some of the methods existing in the literature.

A novel technique to detect the microcalcifications in digital mammograms presented in this paper uses the statistical measures, namely mean and variance, as the criterion to classify the pixels representing microcalcifications. This method has proved its credentials by accurately segmenting the microcalcifications in the mammogram image. This approach fixes the boundary of the microcalcifications accurately, which confirms, its qualitative performance.

Antenna is one of the important elements in the RF system for receiving or transmitting the radio wave signals from and into the air as a medium. The microstrip patch antenna is the most preferred for low cost and compact design. In this paper, a microstrip patch antenna mounted over a high impedance electromagnetic bandgap (EBG) substrate using square and circular shaped unit cells is proposed. A wide operating bandwidth of a microstrip patch antenna can be obtained by arranging EBG patches in two rows. The proposed antenna design is simulated on electromagnetic (EM) simulation software using FR-4 substrate with dielectric constant of 4.54 and thickness of 1.60mm. This antenna has a compact structure with a total size of 60x60mm square. The bandwidth of microstrip patch antenna is enhanced by replacing a conducting ground plane by a high impedance EBG layer. It is also found that the circular shaped EBG cells exhibits higher bandwidth than that of the square shaped EBG cells having same area. A novel design of this microstrip patch antenna is integrated with square and circular unit cells which exhibits significantly wider bandwidth than the conventional one. The bandwidth of microstrip patch antenna using square shaped unit cells is found to be 11.40% and that of circular shaped unit cells is 16.65% which is much higher than that of conventional antenna without EBG substrate whose bandwidth is calculated to be 4.28%. The simulated results show the good agreement with the proposed scheme.

This paper presents two new algorithms for fault classification in power signals. The first algorithm is based on empirical mode decomposition (EMD) of the power signals which decomposes a signal into intrinsic mode functions (IMF). In the proposed technique we obtain the IMFs of the power signals and compute the higher order statistical parameters of each IMF, and a dictionary of feature vectors of different types of faults is prepared. To classify the fault in a given signal, its feature vector is computed and its classification is done using the nearest neighbor rule using its Euclidean distance with the feature vectors stored in the dictionary. The simulation results show that we are able to classify the faults accurately using HOS based approach even at signal-to-noise ratio (SNR) value of 10 dB, which is much lower than the values of SNR reported in the literature. The second method is based on computing the histograms of different types of fault signals and computing their distances with histograms of signals stored in the dictionary. It is observed that above SNR value of 30 dB, we are able to classify all types of faults accurately and this method is computationally less demanding.

The security of digital data including images has attracted more attention recently, and many different image encryption methods have been proposed in the literature for this purpose. In this paper, a new image encryption method using wavelet packet decomposition and discrete linear canonical transform is proposed. The use of wavelet packet decomposition and DLCT increases the key size significantly making the encryption more robust. Simulation results of the proposed technique are also presented.

A new design of a single-feed truncated elliptical patch antenna with and without slots for broadband performance with stacked arrangement is proposed in this paper and its performance is tested in free space. This multilayered rectangular microstrip antenna is designed and analyzed by using the ie3d simulation software. In between conducting and ground plane, designed antenna has two glass epoxy fr-4 substrates separated by an air substrate to attain broadband performance. The impedance bandwidth of designed antenna is better than 2.11GHz or 60% with respect to the central frequency. The simulated e plane co and cross radiation patterns are identical in shape for most of the part of bandwidth however at higher frequency side due to the presence of higher modes and cross polarization the radiation pattern are no more directive normal to patch geometry.

Image restoration using Wiener and geometric mean filtering is one of the commonly used techniques in image processing applications. In this paper we propose the use of discrete fractional Fourier transform in place of conventional discrete Fourier transform (DFT) in the Wiener and geometric mean filters. The use of discrete fractional Fourier transform (DFrFT) provides us additional degree of freedom in terms of the angle parameter of the transforms which can be exploited for the purpose of image restoration. The proposed restoration filters are applied on both colored and grey images and the simulation results of the proposed technique are presented. The effect of variation of parameters of the transforms and filters are also studied under the presence of noise. It is observed that the results of the conventional Wiener and geometric mean filters are better than the filters using DFrFT except for a specific value of the angle parameter about 0.8.

3-D VLSI circuit is becoming a hot issue because of its potential of enhancing performance, while it is also facing challenges such as the increased complexity on floorplanning and placement in VLSI Physical design. Efficient 3-D floorplan representations are needed to handle the placement optimization in new circuit designs. We analyze and categorize some state-of-the-art 3-D representations, and propose a Ternary tree model for 3-D nonslicing floorplans, extending the B*tree from 2D.This paper proposes a novel optimization algorithm for packing of 3D rectangular blocks. The new techniques considered are Differential evolutionary algorithm (DE) is very fast in that it evaluates the feasibility of a Ternary tree representation. Experimental results based on MCNC benchmark with constraints show that our proposed Differential Evolutionary (DE) can quickly produce optimal solutions.

When a patch antenna is fabricated, dimensions of the patch may be slightly different from the designed values due to tolerances in the fabrication process. This alters the resonance frequency of the antenna. To overcome this problem this paper presents a new design approach for fine tuning the resonance frequency by dielectric constant engineering. This approach is especially suited to low temperature co-fired ceramic (LTCC) and similar processes where the antenna dielectric is composed of several layers. Composite dielectric constant of this multilayer structure is altered in such a way that the resonant frequency is set back to the designed value. It has been verified that for proposed micro strip antenna (MSA) design, the frequency-area curve follows a quadratic relation with a variable R (Ratio of cavity area to the patch area). This mathematical model is true up to R 1.27. After this saturation effects set in and the curve follows a straight line behavior.≡

The transmission performance of 20Gbps system has been measured using five FBGs in cascade. Apodized FBG with tanh index profile is optimized for low dispersion at 0.4 nm bandwidth. The simulation results are obtained for 20Gbps in terms of Q-factor and BER. The results are also compared with 10Gbps system.

Wireless sensor networks (WSNs) provide a low cost solution in diversified application areas. The wireless sensor nodes are inexpensive tiny devices with limited storage, computational capability and power. They are being deployed in large scale in both military and civilian applications. Security of the data is one of the key concerns where large numbers of nodes are deployed. Here, an energy-efficient secure routing protocol, secure-LEACH (Low Energy Adaptive Clustering Hierarchy) for WSNs based on the Advanced Encryption Standard (AES) is being proposed. This crypto system is a session based one and a new session key is assigned for each new session. The network (WSN) is divided into number of groups or clusters and a cluster head (CH) is selected among the member nodes of each cluster. The measured data from the nodes is aggregated by the respective CH’s and then each CH relays this data to another CH towards the gateway node in the WSN which in turn sends the same to the Base station (BS). In order to maintain confidentiality of data while being transmitted, it is necessary to encrypt the data before sending at every hop, from a node to the CH and from the CH to another CH or to the gateway node.

In this paper, rectangular wave guides have been analyzed using a square wave incidence which can be used for digital communicat ion techniques . The E 1/mnmode of propagation is solved using Eigen functions taking transverse propagation constant in different regions of dielectric waveguide and then the characteristic equations have been derived. The characteristic equations are solved graphically by mode matching inside and outside fields of waveguide. The normalized propagation constant so obtained, for square wave incidence is compared with the sinusoidal wave obtained by Marcatili method and other methods. The results match fairly well at frequencies near the cut-off of dielectric waveguide.

In this work, platinum (Pt) and palladium (Pd) doped SnO₂ thick film sensors have been developed using solid state derived tin oxide powder. Thick film sensors were fabricated on a 1˝x1˝ alumina substrate. The crystal structure and particle size are confirmed by X-ray diffraction (XRD) pattern. The fabricated sensors are tested for varying concentration (1–5%) of hydrogen and methane gas at different operating temperatures (200–350 °C). The effect of Pt and Pd doping have been analysed on different operating temperature, sensitivity and response/recovery time. The doping effects are also very important from view point of the gas selectivity. Based on the experimental results, we have observed the formation of tetragonal structure and particle size of the powders is drastically decreases from 26 to 19 nm after replacing the platinum dopant with palladium. Both the doped sensors have been found to be sensitive for hydrogen as compare to methane however, Pd-doped SnO₂ sensor are most selective for hydrogen with very fast response and recovery time (20 s, 101 s) due to the small size effect.