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International Journal on Communications Antenna and Propagation - February 2011 (Vol. 1 N. 1) - Papers

Design and Analysis of non–Uniform Spacing Broad–Band Antenna Arrays using Fractional Fourier Transform
Increase of the Gain of a Miniature Ultra Wide Band Antenna using Short-Circuit Wires
Design of Dynamic Phased Array Smart Antenna Using Fourier Series Method
Contribution to the Characterization of Rubble on the Frequency Band [300MHz-3GHz]
Planar Materials Electromagnetic Shielding Efficiency Derivation
CMOS Class AB Power Amplifier Linearization by Feed Forward Technique for Wireless Communications
Performance Evaluation of the FPRRA Framework for GEO Satellites in the Absence of Accurate Multimedia Traffic Prediction
Ultra Wide-Band CMOS Digital Transmitter IC for Low-Power Biomedical Radar Sensing and Sensor Network: Design and Evaluation
LECSOM: a Low-Energy Routing Algorithm based on SOM Clustering for Static and Mobile Wireless Sensor Networks
Microstrip Diplexers with Double-Stub Bandpass Filters
Evaluation of Probability of Transmitted Pilot Bit Error on Multi-Path Fading Channels and Using it in Estimating the Mobile Station Speed
Analysis of H-Plane Tee Junction Coupled through an Inclined Slot in the Narrow Wall of a Rectangular Waveguide
On DPA-Resistive Implementation of FSR-based Stream Ciphers using WDDL Logic Styles
A New Chirp–based Wavelet for Heart Sounds Time–Frequency Analysis
A Tutorial on Network Security: Attacks and Controls
Probabilistic Scheme Fusion Adopted for a Mobile Localization System
Performance of Proposed Algorithm Based on Distributed Dynamic Channel Allocation
Low Power Pilpelined FIR Filter With Enhanced Row Bypassing Multiplier

International Journal on Communications Antenna and Propagation - Papers

Design and Analysis of non–Uniform Spacing Broad–Band Antenna Arrays using Fractional Fourier Transform
by A. S. Srinivasa Rao, P. Mallikarjuna Rao, S.K. Nayak

Vol. 1. n. 1, pp. 1-7

Abstract - Use of frequency independent antennas becomes important in the field of transmitting or receiving spread spectrum signals. For linear arrays the beamwidth depends on length of array and input signal frequency. The main requirement of wideband beamformer is, the main beam pattern should be constant even there is a change in input signal frequency. This paper presents the design of unequal spaced broad band antenna using Fractional Fourier Transform. By using nonuniform spacing the sidelobe level has been achieved to -30dB.

Keywords: Linear Array, Wideband Antenna, Continuous Time Fourier Transform (CTFT), Fractional Fourier Transform (FRFT), Non-Uniform Spacing.

  Increase of the Gain of a Miniature Ultra Wide Band Antenna using Short-Circuit Wires
         by L. Desrumaux, M. Lalande, V. Bertrand, J. Andrieu, B. Jecko
          Vol. 1. n. 1, pp. 8-12

Abstract - A method allowing the increase of the gain of an Ultra Wide Band (UWB) antenna with the addition of short-circuit wires on particular positions is proposed in this paper. The aim is to destruct the radiations in several dimensions to reconstruct them in another one. With this principle, the gain can be increased from 2dB to 5dB without modifying the global dimensions of the antenna. Firstly, the paper presents the principle of addition of short-circuit wires on a bi-cone antenna and then presents its impact on an UWB antenna working in the frequency band 800MHz - 8GHz : the Shark antenna. The performances of the Shark antenna are compared without and with these short-circuit wires and the advantages and drawbacks involved are discussed.

Keywords: Radiation Pattern, UWB Antenna, Wires.

  Design of Dynamic Phased Array Smart Antenna Using Fourier Series Method
         by Abhishek Rawat, R. N. Yadav, S. C. Shrivastava
          Vol. 1. n. 1, pp. 13-16

Abstract - The dynamically phased array smart antenna is an antenna which control its own pattern by means of feed-back or feed-forward control, and performs gain enhancement for desired signals whereas suppression for interfering signals. The array forms a beam by activating certain elements in the array, which have a multiplying effect to form a beam. This beam can then be steered or pointed in the direction of a device by phasing the transmission of the signal in the elements and adjusting the gain on each antenna element. In this paper design of dynamically phased array smart antenna based on Fourier series method and Radial basis neural network are proposed. In this approached the half wave dipole leg used to create desired radiation pattern in appropriate direction and suppress interference up to certain extent. The result obtained by this network is in excellent agreement with simulation results.

Keywords: Dynamically Phased Array (DPA) Smart Antenna, Fourier series method, Array antenna, Radial Basis Function Neural Network (RBFNN), Smart antenna.

Contribution to the Characterization of Rubble on the Frequency Band [300MHz-3GHz]
by H. Hamieh, M. Jouvet, N. Feix, B. Beillard, E. Martinod, M. Lalande, C. Labarthe

Vol. 1. n. 1, pp. 17-20

Abstract - This letter describes an innovative method of characterization of Building materials on the frequency band [300MHz-3GHz]. Some simulations and measurements have been done to deduce the electromagnetic behavior through the rubble with specific dielectric properties and different configurations. The key of our characterizations method are presented, measurement and simulation results are illustrated and discussed.

Keywords: Permittivity Measurement, Transient Analysis, Underground Electromagnetic Propagation.

Planar Materials Electromagnetic Shielding Efficiency Derivation
by L. Vojtech, M. Neruda, J. Hajek

Vol. 1. n. 1, pp. 21-28

Abstract - One of the main instruments of ensuring electromagnetic compatibility standard demands on electrotechnical devices is called electromagnetic shielding. Research and development of elements based on for example composite layer setting with specific electromagnetic features require an origination of models of these structures. A process of modeling of these materials is derived from model of shielding electromagnetic efficiency of common planar materials. Detailed and complete derivation of published models misses in scientific literature and published approximated equations differ from each other in many cases. It can cause unwanted repetition of mistakes in published equations. This paper is therefore focused on derivation of electromagnetic shielding efficiency of planar materials. Derivation obviates discrepancy published in scientific literature and consequently possible incorrect applications in technical practice. Results of modeling and measurement show a strong dependence of shielding efficiency and material electric conductivity and related equivalent sheet model thickness. This result is in accordance with practical experience from EMC branch.

Keywords: Electromagnetic Shielding Efficiency, Planar Materials, Shielding Efficiency Derivation, Shielding Material.

CMOS Class AB Power Amplifier Linearization by Feed Forward Technique for Wireless Communications

by A. Attaran, S. Nikan, M. Razzaghpour

Vol. 1. n. 1, pp. 29-33

Abstract - This paper presents a class AB PA with an optimized load impedance for maximum output power in a standard 180 nm CMOS technology. This Amplifier shows a measured output power of 22.36 dBm at 2.4 GHz for a supply voltage of 1.8 V. It will display necessary trade offs for optimum output power and small signal gain. Simulation results show that the drain efficiency at 1 dB compression point reaches 31.41%. Additionally, using a feed forward linearization technique, P1-dB is increased to 24.05 dBm which shows 3.46 dB improvement compared to the case without linearization. Enhancement in the amplifier linearity range leads to lower adjacent channel interference and thus higher data transfer rate.

Keywords: Power Amplifier, Linearization, Feed Forward Technique.

Performance Evaluation of the FPRRA Framework for GEO Satellites in the Absence of Accurate Multimedia Traffic Prediction
by Polychronis Koutsakis, Dimitra Vasileiadou, Charalabos Stamos

Vol. 1. n. 1, pp. 34-45

Abstract - In recent work [1] we have introduced and evaluated a fair and dynamic joint Call Admission Control (CAC) and Multiple Access Control (MAC) framework, for Geostationary (GEO) Satellite Systems, named Fair Predictive Resource Reservation Access (FPRRA). The framework was based on accurate videoconference and data traffic prediction, made decisions after taking into account the provider revenue, and was shown to be highly efficient. However, the accurate modeling of multimedia traffic is not always possible, especially in the case of video (i.e., not videoconference) traffic. In this paper we evaluate the performance of FPRRA in the absence of accurate video traffic modeling and we discuss the efficiency of the scheme in comparison to other efficient schemes from the literature.

Keywords: GEO Satellite Systems, Multiple Access Control, Call Admission Control, Video Traffic, Traffic Modeling.

Ultra Wide-Band CMOS Digital Transmitter IC for Low-Power Biomedical Radar Sensing and Sensor Network: Design and Evaluation
by Xubo Wang, Anh Dinh, Daniel Teng

Vol. 1. n. 1, pp. 46-54

Abstract - In this paper, an UWB transmitter for next generation bio-radar sensing system characterized by a high data rate, low area, low power consumption, and low complexity, and specifically designed to fit Canada UWB spectrum mask, is proposed for real-time bio-medical sensing. The proposed IR-UWB radar transmitter requires no clock, yielding higher speed and lower power. The transmitter is based on an all digitally controlled circuit pulse generator in 90nm CMOS to generate the tenth-order derivative of Gaussian pulse with BPSK modulation scheme operating in the 6-10GHz band specified by Canada draft spectrum specification. The output pulse power level is adjustable through an variable gain driver inside the transmitter. The transmitter core occupies an chip area of 200um by 140um. Simulating on a 1V voltage supply, the transmitter draws average 9.037mW when generating the tenth-order Gaussian derivative pulses at a pulse repetition frequency of 50MHz. The transmitter has an output power of 7.08dBm and each pulse has the energy of 3.1pJ/pulse. The pulse is digitally synthesized and BPSK modulated. This transmitter prototype can generate any other pulse combinations with minor design modifications. The predicted performance of the bio-radar is evaluated and discussed.

Keywords: UWB, Digital, Transmitter, Gaussian Pulse, BPSK.

LECSOM: a Low-Energy Routing Algorithm based on SOM Clustering for Static and Mobile Wireless Sensor Networks
by Francine Krief, Younès Bennani, Danielo Gomes, J. Neuman de Souza

Vol. 1. n. 1, pp. 55-63

Abstract - This paper addresses the energy-aware routing problem for both static and mobile wireless sensor networks. In this kind of network, the tradeoff between energy saving and the number of packets received at the base station is a major concern. We propose LECSOM, an low-energy clustering routing algorithm based on topological self-organizing maps learning techniques. We follow a twofold methodology. First, considering static sensor nodes, LECSOM have been simulated and compared, on the same data set, with other two approaches considered in scientific literature. Second, in a mobile scenario, we apply LECSOM with different clusterhead selection criteria to evaluate its reliability and the impact of these criteria. Simulation results show improvements in overall energy saving – the network lifetime grows up to 40 times longer. The network coverage is insured during 90% of the total time for static sensors nodes and 97% for the mobile ones. Moreover, the number of packets received at the base station is increased by 50%.

Keywords: Mobile Wireless Sensor Networks, Clustering, Energy-Saving Routing, SOM.

Microstrip Diplexers with Double-Stub Bandpass Filters
by M. Khalaj-Amirhosseini, M. Moghavvemi, H. Ameri, A. Attaran

Vol. 1. n. 1, pp. 64-67

Abstract - This paper presents a microstrip diplexer using two Double-Stub Band-Pass Filters (DS-BPFs), composed of several double-stubs connected to a main microstrip line. Each DS-BPF has a null at the center frequency of the other. Therefore, these types of filters are suitable for diplexers with two near frequencies. A diplexer at frequencies 5.875 and 6.225 GHz is designed, fabricated and measured. Measured results of the fabricated diplexer have a good agreement with the calculated results.

Keywords: Diplexers; Double-Stubs; Microstrip Transmission Lines.

Evaluation of Probability of Transmitted Pilot Bit Error on Multi-Path Fading Channels and Using it in Estimating the Mobile Station Speed
by Ehsan Ghafarioun, Omid Sharifi-Tehrani, Taymur Khaluei

Vol. 1. n. 1, pp. 68-72

Abstract - In this article the probability of the transmitted pilot bit error with digital modulation in the leveled Rayleigh multi-path fading channel and using it in estimating the mobile station (Doppler channel) by utilizing bit error analysis is simulated. The considered pilot signal which is composed of “1” or “1” bit sequence is transmitted by the base station and under DPSK, FSK, MSK, and BPSK modulations, directly. The Doppler effect is considered as one of the important effects in mobile radio channels on probability of pilot bit errors, and the mobile station speed is estimated by using the relevant results and assuming the definition of the place of occurring the bit errors on the received bit strings for BPSK modulation. The advantages of presented method in calculating the mobile station speed are not requiring to add new hardware and simplicity of calculations. The simulation results indicate the proper potential in estimating the mobile station speed in signal to noise ratio of over 20 dB.

Keywords: Bit Error Probability Evaluation, Estimating Mobile Station Speed, Multi-Path Fading Channel, Digital Modulation, Mobile Radio Communication Systems.

Analysis of H-Plane Tee Junction Coupled through an Inclined Slot in the Narrow Wall of a Rectangular Waveguide
by R. Ramana Reddy,. G.S.N. Raju

Vol. 1. n. 1, pp. 73-82

Abstract - An H-plane Tee junction coupled through a longitudinal slot in the narrow wall of feed guide is a common device and is analyzed by several researchers. Its design for a given application depends on slot length, width, dimensions of feed and coupled guides, frequency of operation, in the region inside the waveguide. However, when the array of such junctions is to be designed for a given application, it is more useful to have more design parameters under the control of the designer without compromising on polarization purity. The design of these arrays demands the knowledge of the admittance characteristics of the junctions. In view of this, a rigorous analysis is carried out to obtain the admittance characteristics of H-plane Tee junctions coupled through an inclined slot. The proposed structure has a new additional parameter namely inclination of the slot to control the admittance characteristics. The analysis consists of the use of self-reaction in the feed and coupled guides and discontinuity in modal current. The variation of Conductance, Susceptance, Coupling and VSWR of the junction as a function of slot length for a fixed slot width, frequency, inclination of slot is obtained and its data is presented in this paper.

Keywords: Inclined Slot, Waveguide, H-Plane Tee Junction, Self-Reaction and Discontinuity in Modal Current, Conductance, Susceptance, Coupling, VSWR.

On DPA-Resistive Implementation of FSR-based Stream Ciphers using WDDL Logic Styles
by R.Ebrahimi Atani, S.Ebrahimi Atani

Vol. 1. n. 1, pp. 83-91

Abstract - Cryptographic embedded systems are vulnerable to Differential Power Analysis (DPA) attacks. In this paper, we will implement two of the focus eSTREAM candidates, the Trivium and Garin stream ciphers, using the WDDL styles. These ciphers are designed by two submicron technologies and simulated by HSpice software. The paper presents the trade-offs involved in designing the architecture, and design for performance issues.

Keywords: DPA Attack, Stream Cipher, Estream, WDDL, CMOS,Trivium, Grain.

A New Chirp–based Wavelet for Heart Sounds Time–Frequency Analysis
by Abdelghani Djebbari, Fethi Bereksi-Reguig

Vol. 1. n. 1, pp. 92-102

Abstract - The present paper investigates the ability of a chirplet model to be considered as a pattern generating a mother wavelet for time–scale analysis of heart sounds. The choice of the mother wavelet is a sensitive task since it affects considerably the obtained time–scale representation. Heart sounds are formed by frequency modulated components; it is therefore convenient to analyze them by means of chirplet rather than ordinary wavelet. Indeed, we study a heart sound valvular component chirplet model to generate an adapted mother wavelet pattern, which is then used within the Continuous Wavelet Transform (CWT). Using the Morlet wavelet and the Discrete Meyer wavelet as comparative approaches, we found that the valvular chirplet model is suitable as mother wavelet for heart sounds time–frequency representation. Indeed, we can reach 98.59% of cross–correlation between the adapted wavelet and the original chirplet for 15 as fitting polynomial order. The VCCM represents adequately more than 80% of the frequency modulated components of both S1 and S2 heart sounds. Therefore, the proposed VCCM wavelet provide better results than the Morlet wavelet and the discrete Meyer wavelet in representing heart sounds energy.

Keywords: Heart Sound, Phonocardiogram, Continuous Wavelet Transform, Morlet Wavelet, Discrete Meyer Wavelet, Chirplet.

A Tutorial on Network Security: Attacks and Controls
by Natarajan Meghanathan

Vol. 1. n. 1, pp. 103-116

Abstract - In order to come up with measures that make networks more secure, it is important to learn about the vulnerabilities that could exist in a computer network and then have an understanding of the typical attacks that have been carried out in such networks. The first half of this paper will expose the readers to the classical network attacks that have exploited the typical vulnerabilities of computer networks in the past and solutions that have been adopted since then to prevent or reduce the chances of some of these attacks. The second half of the paper will expose the readers to the different network security controls including the network architecture, protocols, standards and software/ hardware tools that have been adopted in modern day computer networks.

Keywords: Network Security, Attacks, Controls, IP Sec, SSH, TLS, Firewalls, Kerberos.

Probabilistic Scheme Fusion Adopted for a Mobile Localization System
by Fterich Souhir, Mhamdi Halima, R. B. Chibani, Med.N. Abdelkrim

Vol. 1. n. 1, pp. 117-127

Abstract - This research work is part of mobile communications; particularly, it deals with geographic localization. This research-field is nowadays becoming the center of interest of the scientific community. Actually, a great interest is given to the location theme; it has become the most interesting subject of all discussions. Many other works and researches are eventually adopted by the literature. However, the retained approaches seem not to satisfy the customer’s aims. The precision, as a performance criterion, has to be improved. Data fusion is a new approach that should intervene in order to better locate our customers and to procure the best results. Thus, we are trying, through this paper, to explore the probability-field. In fact, this context suggests its own fusion schemes and its proper features. Especially, the Bayesian scheme requires means for incertitude and accuracy modelling. This concept should notably intervene in describing consistence and reliability problems. Hybrid localization solutions are then proposed through out these approaches in order to improve actual localization system.

Keywords: Data fusion, Localization, Probabilities, to locate, Localization system.

Performance of Proposed Algorithm Based on Distributed Dynamic Channel Allocation
by Y. S. V. Raman, B. Prabhakara Rao, S. Sri Gowri

Vol. 1. n. 1, pp. 128-131

Abstract - In cellular networks, channels should be allocated efficiently to support communication between mobile hosts. When mobile hosts move from one cell to another cell to provide uninterrupted service, the new cell should have enough channels to support the ongoing communication of the mobile hosts that moved into the cell. Allocation of channels to individual cells can be done either by a centralized method or a distributed method. Under both approaches, available channels can be either pre-allocated to cells initially or can be allocated to them whenever the need for additional channels arises. The objective of proposed algorithm is to increase the spectral efficiency and throughput of the system for an increase in channels which is based on a distributed dynamic channel allocation technique.

Keywords: spectral efficiency, throughput, distributed dynamic channel allocation.

Low Power Pilpelined FIR Filter With Enhanced Row Bypassing Multiplier
by Sriadibhatla Sridevi, Appsani v v s Chowdary

Vol. 1. n. 1, pp. 132-135

Abstract - This paper presents a low power FIR filter with enhanced row bypassing multipliers. Direct form architecture with pipelined stage is chosen for implementation. The presence of power efficient enhanced row bypassing multiplier, adapting clocked CMOS logic for realizing circuitry, reduces the power consumption of the fir filter to a larger extent. The essence of power saving idea is eliminating unnecessary computations via signal bypassing. The proposed architectures have been implemented on Virtex 2VP2 fg256-7 field-programmable gate array and synthesized on 1.2 μm complementary metal oxide semiconductor technology. Synthesis results show that the proposed architecture offer good area and power reductions and speed improvement compared to the existing FIR filter implementations.

Keywords: low power, FIR Filter, clocked CMOS, bypassing.