Vol. 132
Latest Volume
All Volumes
PIER 176 [2023] PIER 175 [2022] PIER 174 [2022] PIER 173 [2022] PIER 172 [2021] PIER 171 [2021] PIER 170 [2021] PIER 169 [2020] PIER 168 [2020] PIER 167 [2020] PIER 166 [2019] PIER 165 [2019] PIER 164 [2019] PIER 163 [2018] PIER 162 [2018] PIER 161 [2018] PIER 160 [2017] PIER 159 [2017] PIER 158 [2017] PIER 157 [2016] PIER 156 [2016] PIER 155 [2016] PIER 154 [2015] PIER 153 [2015] PIER 152 [2015] PIER 151 [2015] PIER 150 [2015] PIER 149 [2014] PIER 148 [2014] PIER 147 [2014] PIER 146 [2014] PIER 145 [2014] PIER 144 [2014] PIER 143 [2013] PIER 142 [2013] PIER 141 [2013] PIER 140 [2013] PIER 139 [2013] PIER 138 [2013] PIER 137 [2013] PIER 136 [2013] PIER 135 [2013] PIER 134 [2013] PIER 133 [2013] PIER 132 [2012] PIER 131 [2012] PIER 130 [2012] PIER 129 [2012] PIER 128 [2012] PIER 127 [2012] PIER 126 [2012] PIER 125 [2012] PIER 124 [2012] PIER 123 [2012] PIER 122 [2012] PIER 121 [2011] PIER 120 [2011] PIER 119 [2011] PIER 118 [2011] PIER 117 [2011] PIER 116 [2011] PIER 115 [2011] PIER 114 [2011] PIER 113 [2011] PIER 112 [2011] PIER 111 [2011] PIER 110 [2010] PIER 109 [2010] PIER 108 [2010] PIER 107 [2010] PIER 106 [2010] PIER 105 [2010] PIER 104 [2010] PIER 103 [2010] PIER 102 [2010] PIER 101 [2010] PIER 100 [2010] PIER 99 [2009] PIER 98 [2009] PIER 97 [2009] PIER 96 [2009] PIER 95 [2009] PIER 94 [2009] PIER 93 [2009] PIER 92 [2009] PIER 91 [2009] PIER 90 [2009] PIER 89 [2009] PIER 88 [2008] PIER 87 [2008] PIER 86 [2008] PIER 85 [2008] PIER 84 [2008] PIER 83 [2008] PIER 82 [2008] PIER 81 [2008] PIER 80 [2008] PIER 79 [2008] PIER 78 [2008] PIER 77 [2007] PIER 76 [2007] PIER 75 [2007] PIER 74 [2007] PIER 73 [2007] PIER 72 [2007] PIER 71 [2007] PIER 70 [2007] PIER 69 [2007] PIER 68 [2007] PIER 67 [2007] PIER 66 [2006] PIER 65 [2006] PIER 64 [2006] PIER 63 [2006] PIER 62 [2006] PIER 61 [2006] PIER 60 [2006] PIER 59 [2006] PIER 58 [2006] PIER 57 [2006] PIER 56 [2006] PIER 55 [2005] PIER 54 [2005] PIER 53 [2005] PIER 52 [2005] PIER 51 [2005] PIER 50 [2005] PIER 49 [2004] PIER 48 [2004] PIER 47 [2004] PIER 46 [2004] PIER 45 [2004] PIER 44 [2004] PIER 43 [2003] PIER 42 [2003] PIER 41 [2003] PIER 40 [2003] PIER 39 [2003] PIER 38 [2002] PIER 37 [2002] PIER 36 [2002] PIER 35 [2002] PIER 34 [2001] PIER 33 [2001] PIER 32 [2001] PIER 31 [2001] PIER 30 [2001] PIER 29 [2000] PIER 28 [2000] PIER 27 [2000] PIER 26 [2000] PIER 25 [2000] PIER 24 [1999] PIER 23 [1999] PIER 22 [1999] PIER 21 [1999] PIER 20 [1998] PIER 19 [1998] PIER 18 [1998] PIER 17 [1997] PIER 16 [1997] PIER 15 [1997] PIER 14 [1996] PIER 13 [1996] PIER 12 [1996] PIER 11 [1995] PIER 10 [1995] PIER 09 [1994] PIER 08 [1994] PIER 07 [1993] PIER 06 [1992] PIER 05 [1991] PIER 04 [1991] PIER 03 [1990] PIER 02 [1990] PIER 01 [1989]
2012-10-19
PIER
Vol. 132, 603-619, 2012
download: 202
Tubular Linear Induction Machine as a Fast Actuator: Analysis and Design Criteria
Antonino Musolino Rocco Rizzo Ernesto Tripodi
In this paper, some design criteria for a Tubular Linear Induction Motor (TLIM) as a fast actuator are considered. The in fluence of geometrical and physical parameters on the operating conditions of a TLIM are investigated by means a quasi-analytic model. The model is based on the application of the Fourier Transform both in space and in time. The Fourier transform in space is introduced to take into account the finite length of the stator windings in the axial direction. The transient electrical response of the motor at standstill following the insertion of a three-phase system of voltage generators is performed by the Fourier transform in the time.
TUBULAR LINEAR INDUCTION MACHINE AS A FAST ACTUATOR: ANALYSIS AND DESIGN CRITERIA
2012-10-16
PIER
Vol. 132, 587-601, 2012
download: 135
Coupling Effect for Dielectric Metamaterial Dimer
Fuli Zhang Veronique Sadaune Lei Kang Qian Zhao Ji Zhou Didier Lippens
In this paper, we report experimentally and numerically on coupling effects of dielectric metamaterial dimer (metadimer) which composed of two identical ceramic cubes with high permittivity. The distance dependence of Mie resonance for metadimer is investigated under various polarizations of external wave. By changing the configurations and alignment of dimer resonator, it is revealed that magnetic and electric resonances of metadimer exhibits a red/blue shift, resulting from longitudinal or transverse coupling effects of dipoles. Besides, quasi bound states between tightly stacked dielectric cubes are also been pointed out for electric Mie resonance, which is responsible for an unexpected frequency shift with a reverse variation.
COUPLING EFFECT FOR DIELECTRIC METAMATERIAL DIMER
2012-10-16
PIER
Vol. 132, 571-586, 2012
download: 180
Interferometric ISAR Imaging on Maritime Target Applications: Simulation of Realistic Targets and Dynamics
David Felguera-Martin Jose-Tomas Gonzalez-Partida Mateo Burgos-Garcia
ISAR imaging of maritime targets has greater success than other ISAR applications due to the constant oscillatory motions induced by waves and wind. However, relative target motions are usually unknown, difficult focusing, image interpretation and target classification. Using interferometry to obtain the height information makes possible to obtain a 3-D reconstruction of a target, aiding image focusing, image interpretation and target classification. However, the information and utility of the ISAR image and the interferometric information depends highly on geometry and targets dynamics. In this paper we will study the influence of movement dynamics in interferometric ISAR imaging using a realistic extended moving target simulation, a general geometry and complex dynamics models.
INTERFEROMETRIC ISAR IMAGING ON MARITIME TARGET APPLICATIONS: SIMULATION OF REALISTIC TARGETS AND DYNAMICS
2012-10-15
PIER
Vol. 132, 551-570, 2012
download: 146
Simple Formula and Its Exact Analytic Solution of Mutual Impedance for Nonplanar-Skew Dipoles
Jung-Hoon Han Won-Young Song Kyoung-Sub Oh Noh-Hoon Myung
The analysis of an antenna mutual coupling is a significant issue for designing the wireless communication system especially includes an array mutual coupling problem. The accurate analysis of the mutual coupling between antennas is needed. Accordingly, several methods for the mutual impedance calculation of dipoles have been studied in cases of coplanar-skew and nonplanar-skew. This paper proposes an exact and simple method for analyzing the mutual impedance between two arbitrarily located and slanted dipoles using the modified induced EMF method; their expressions and the exact analytic solution. The proposed formula and their closed-form solutions are verified by numerical solution using HFSS and give good agreement.
SIMPLE FORMULA AND ITS EXACT ANALYTIC SOLUTION OF MUTUAL IMPEDANCE FOR NONPLANAR-SKEW DIPOLES
2012-10-15
PIER
Vol. 132, 517-549, 2012
download: 105
Development of a Symplectic Scheme with Optimized Numerical Dispersion-Relation Equation to Solve Maxwell's Equations in Dispersive Media
Tony Wen-Hann Sheu Rih Yang Chung Jia-Han Li
In this paper an explicit finite-difference scheme is developed in staggered grids for solving the Maxwell's equations in time domain. We are aimed to preserve the discrete zero-divergence condition in the electrical and magnetic fields and conserve the inherent laws in non-dispersive simple media all the time using the explicit second-order accurate symplectic partitioned Runge-Kutta temporal scheme for the time derivative terms. The spatial derivative terms in the semi-discretized Faraday's and Ampere's equations are then approximated to get an accurate numerical dispersion relation equation that governs the numerical angular frequency and the wavenumbers for the Maxwell's equations defined in two space dimensions. To achieve the goal of getting the best dispersive characteristics in the chosen grid stencil, a fourth-order accurate space centered scheme with the ability of minimizing the difference between the exact and numerical dispersion relation equations is proposed. Our emphasis is placed on the accurate modeling of EM waves in the dispersive media of the Debye, Lorentz and Drude types. Through the computational exercises, the proposed dual-preserving Maxwell's equation solver is computationally demonstrated to be efficient for use to predict the long-term accurate wave solutions in a medium belonging either to a frequency independent or to a dependent type.
DEVELOPMENT OF A SYMPLECTIC SCHEME WITH OPTIMIZED NUMERICAL DISPERSION-RELATION EQUATION TO SOLVE MAXWELL'S EQUATIONS IN DISPERSIVE MEDIA
2012-10-11
PIER
Vol. 132, 499-515, 2012
download: 173
A Wideband Dual-Polarized Patch Antenna with Electric Probe and Magnetic Loop Feeds
Jiao-Jiao Xie Ying-Zeng Yin Jian Ren Tuo Wang
A new wideband dual-polarized patch antenna consisting of a magnetically-fed and an electrically-fed is presented in the paper. The two feeds are orthogonal to each other at the center of the ground plane and generate 0° and 90° polarization separately. Two pairs of L-shaped slots are etched in the radiating patch to improve the impedance bandwidth. By using a shorting pin connecting the radiating patch to the ground plane, the coupling between the two feeding ports can be reduced. With the help of circuit simulation and full wave simulation, the equivalent circuit model of the antenna is established. The simulated and measured results show that the impedance bandwidths for VSWR less than 2 of the proposed dual-polarized antenna with a profile of are 27.3% (3.29-4.33 GHz) and 19% (3.05-3.69 GHz) for 0° polarization and 90° polarization, respectively, with a height of 0.08 λ0 between radiating patch and ground plane. The measured coupling between the two ports is below -20 dB over the operating band. Moreover, the measured gain of the proposed antenna is about 7.9 dBi and 6.1 dBi for port 1 and port 2, respectively, over the operating band. Measured results of the fabricated antenna prototypes are in good agreement with the simulated results.
A WIDEBAND DUAL-POLARIZED PATCH ANTENNA WITH ELECTRIC PROBE AND MAGNETIC LOOP FEEDS
2012-10-09
PIER
Vol. 132, 479-498, 2012
download: 121
Performance Evaluation of UWB on-Body Communication Under WiMAX off -Body EMI Existence
An-Ming Gao Qi Hao Xu Hong-Li Peng Wei Jiang Yong Jiang
A study of UWB on-body communication system performance, with the WiMax off-body electromagnetic interference (EMI) existence, is presented. Firstly, a compact UWB antenna with good on-body performance is verified and chosen as our reference antenna. Using this realistic antenna, channel transfer function (CTF) of UWB on-body channel in an indoor room is investigated by measurements. Based on the measured data, the parameters of its pathloss model and its power delay profile (PDP) model are extracted respectively. Secondly, a new body channel communication system model, composed of the on-body and off-body dual-link channel, together with UWB and WiMax signal models are presented. Finally, UWB on-body communication performances under different WiMax off-body EMI levels are studied by simulation. Simulated results show that this on-body system performance is quite limited and easily affected by the off-body WiMax EMI. It is pointed out that the existing UWB on-body communication abilities should be greatly improved when WiMax off-body EMI signals are considered.
PERFORMANCE EVALUATION OF UWB ON-BODY COMMUNICATION UNDER WIMAX OFF-BODY EMI EXISTENCE
2012-10-08
PIER
Vol. 132, 463-478, 2012
download: 229
A Detached Zero Index Metamaterial Lens for Antenna Gain Enhancement
Fan-Yi Meng Yue-Long Lyu Kuang Zhang Qun Wu Joshua Le-Wei Li
In this paper, a detached zero index metamaterial lens (ZIML) consisting of metal strips and modified split ring resonators (MSRRs) is proposed for antenna gain enhancement. The effective permittivity and permeability of the detached ZIML are designed to synchronously approach zero, which leads the ZIML to having an effective wave impedance matching with air and near-zero index simultaneously. As a result, neither does the detached ZIML need to be embedded in horns aperture nor depends on auxiliary reflectors in enhancing antenna gain, which is quite different from conventional ZIMLs. Moreover, the distance between antenna and the detached ZIML slightly affect the gain enhancement, which further confirms that the ZIML can be detached from antennas. Simulated results show that the effective refractive index of the detached ZIML is near zero in a broad frequency range where the effective relative wave impedance is close to 1. The detached ZIML is fabricated and tested by placing it in front of an H-plane horn antenna. One finds that evident gain enhancement is obtained from 8.9 GHz to 10.8 GHz and the greatest gain enhancement reaches up to 4.02 dB. In addition, the detached ZIML can also work well at other frequencies by adjusting its geometric parameters to scale, which is demonstrated by designing and simulating two detached ZIMLs with center frequencies of 2.4 GHz and 5.8 GHz, respectively.
A DETACHED ZERO INDEX METAMATERIAL LENS FOR ANTENNA GAIN ENHANCEMENT
2012-10-05
PIER
Vol. 132, 443-461, 2012
download: 256
Kalman Filter for Removal of Scalloping and Inter-Scan Banding in Scansar Images
Mahboob Iqbal Jie Chen Wei Yang Pengbo Wang Bing Sun
Spaceborne synthetic aperture radar (SAR) plays more and more important role in Earth observation science, especially with ScanSAR mode which provides wide-swath coverage with moderate resolution. However, scalloping and inter-scan banding (ISB) are two major artifacts, which signi cantly degrade the quality of ScanSAR images. In this paper, a novel technique for removal of scalloping and ISB in ScanSAR images is proposed. Scalloping and ISB artifacts are modeled by two-dimensional gain and o set parameters varying as function of both azimuth time and range position. The gain and o set parameters can be split into azimuth and range components. The variations of gain/o set with respect to azimuth and range positions would represent scalloping and ISB artifacts respectively. In the proposed technique, recursive and minimum mean square error (MMSE) estimates of azimuth gain/o set parameters are found out by using Kalman lter for each azimuth location in a subswath by considering corresponding range samples as observation vector. Subsequently, range gain/o set parameters causing ISB artifacts are estimated by using Kalman lter for each range positions by considering azimuth samples as observation vector. The MMSE estimates of gain/o set parameters are used to directly remove scalloping and ISB artifacts. The proposed scheme was applied on simulated as well as calibrated real ScanSAR images. The experimental results exhibited the potential of proposed technique to be used as post processing tool for enhancing ScanSAR image quality.
KALMAN FILTER FOR REMOVAL OF SCALLOPING AND INTER-SCAN BANDING IN SCANSAR IMAGES
2012-10-05
PIER
Vol. 132, 425-441, 2012
download: 136
Retrieval of Effective Electromagnetic Parameters of Isotropic Metamaterials Using Reference-Plane Invariant Expressions
Ugur Cem Hasar Joaquim Jose Barroso Cumali Sabah Ibrahim Yucel Ozbek Yunus Kaya Deniz Dal Tolga Aydin
Three different techniques are applied for accurate constitutive parameters determination of isotropic split-ring resonator (SRR) and SRR with a cut wire (Composite) metamaterial (MM) slabs. The first two techniques use explicit analytical calibration-dependent and calibration-invariant expressions while the third technique is based on Lorentz and Drude dispersion models. We have tested these techniques from simulated scattering (S-) parameters of two classic SRR and Composite MM slabs with various level of losses and different calibration plane factors. From the comparison, we conclude that whereas the extracted complex permittivity of both slabs by the analytical techniques produces unphysical results at resonance regions, that by the dispersion model eliminates this shortcoming and retrieves physically accurate constitutive parameters over the whole analyzed frequency region. We argue that incorrect retrieval of complex permittivity by analytical methods comes from spatial dispersion effects due to the discreteness of conducting elements within MM slabs which largely vary simulated S-parameters in the resonance regions where the slabs are highly spatially dispersive.
RETRIEVAL OF EFFECTIVE ELECTROMAGNETIC PARAMETERS OF ISOTROPIC METAMATERIALS USING REFERENCE-PLANE INVARIANT EXPRESSIONS
2012-10-05
PIER
Vol. 132, 403-424, 2012
download: 126
Scattering of an Arbitrarily Oriented Dipole Field by a Circular Disk with Surface Impedance
Allah Ditta Ulfat Jafri Qaisar Naqvi Aqeel Abbas Syed Kohei Hongo
The scattering of an arbitrarily oriented dipole field by a circular disk with surface impedance is investigated by using the method of Kobayashi Potential (KP method). The dual integral equations (DIE) are produced during formulation of the problem. The solution of the DIEs is constructed in terms of set of functions which satisfy the boundary conditions as well as required edge conditions. At this stage, we applied the discontinuous properties of Weber Schafheitlins integral and vector Hankel transform. After applying the projection, the resulting expressions are reduced to the matrix equations for the expansion coefficients. The matrix elements are given in terms of the infinite integrals. The far field patterns for the scattered wave are computed for different incident angles, disk sizes and surface impedances for ρ−, Φ− and z−directed dipole field excitation. To validate the results we have obtained the results based on the physical optics approximation and their comparison shows that they quite reasonably match.
SCATTERING OF AN ARBITRARILY ORIENTED DIPOLE FIELD BY A CIRCULAR DISK WITH SURFACE IMPEDANCE
2012-10-03
PIER
Vol. 132, 389-402, 2012
download: 125
Soft-Focusing in Anisotropic Indefinite Media through Hyperbolic Dispersion
Sara Wheeland Alireza V. Amirkhizi Sia Nemat-Nasser
Materials that exhibit negative refraction may have many novel applications. We seek to evaluate the possibility of soft-focusing of microwave signals using a medium with an indefinite (hyperbolic) anisotropic permittivity tensor. We fabricated a 147 mm thick and 220 mm wide Styrofoam sample with an embedded array of 12-gauge brass wires of 6.35 mm lattice spacing. Two single-loop antennas were used to approximately generate a transverse magnetic (TM) point source and the associated detector. Using an Agilent 8510C Vector Network Analyzer (VNA), the frequency spectrum was scanned between 7 and 9 GHz. Relative gain or loss measurements were taken at equal spatial steps behind the sample. A scanning robot was used for automatic scanning in the x, y, and z directions, in order to establish the focusing patterns. The signal amplitudes measured in the presence and absence of the sample were compared. The robot was controlled using LabVIEW1, which also collected the data from the VNA and passed it to MATLAB2 for processing. A soft focusing spot was observed when the antennas were placed in two different symmetric configurations with respect to the sample. These results suggest a method for focusing electromagnetic waves using negative refraction in indefinite (hyperbolic) anisotropic materials.
SOFT-FOCUSING IN ANISOTROPIC INDEFINITE MEDIA THROUGH HYPERBOLIC DISPERSION
2012-10-02
PIER
Vol. 132, 369-388, 2012
download: 226
Design and Validation of a TEM Cell Used for Radiofrequency Dosimetric Studies
Cora Iftode Simona Miclaus
A Transverse Electromagnetic Mode (TEM) cell is one interesting alternative for studies of biological effects of radiofrequency radiation at reduced scale (in vitro studies). Controlled and well-characterized exposure conditions are essential for a concluding investigation: the biological sample has to be exposed to a uniform incident electromagnetic wave and the dose of absorbed radiation has to be precisely determined and correlated with the effect. Unfortunatelly, many times experimental dosimetry is either unavailable or unappliable, so that a pre-characterised and validated experimental set-up is mostly valuable. In this regard, the main objective of present work was to experimentally validate a computational model of an own-built TEM cell designed for bioelectromagnetic experiments in frequency range of 100MHz-1GHz. For validation, three significant parameters were investigated comparatively, by measurements and by computation: scattering parameters; incident electric field distribution; absorbed power in a set of liquid samples. By using the finite integration technique (FIT) method implemented by the commercial code CST Microwave Studio, and by using a vector network analyzer in the experimental approach, we validated the designed TEM cell and characterized it successfully. The second objective was a dosimetric study of four different liquid samples loaded in the cell. We used the absorption coefficient (AC) which may be assimilated to the specific absorption rate (SAR) of energy deposition in the whole sample volume. AC was shown to converge in experiment and simulation up to 800MHz for all samples. AC didn't depend directly upon sample's volume (even if, frequently, greater volumes showed higher absorption) but rather upon the internal field distribution in the sample, distribution that mostly depends on the frequency and on the dimensions of the liquid samples.
DESIGN AND VALIDATION OF A TEM CELL USED FOR RADIOFREQUENCY DOSIMETRIC STUDIES
2012-10-02
PIER
Vol. 132, 347-368, 2012
download: 160
Spatial Correlation of Multiple Antenna Arrays in Wireless Communication Systems
Ju-Hong Lee Ching-Chia Cheng
This paper investigates the spatial correlation characteristics of multiple antenna arrays deployed in wireless communication systems. First, we derive a general closed-form formula for the spatial correlation function (SCF) of a multiple antenna array with arbitrary array configuration under uniform signal angular energy distribution. Based on this formula, we then explore the characteristics of the SCF for several multiple antenna arrays with different array geometries. It is found that a multiple antenna array with a three-dimensional (3-D) array geometry can reduce the magnitude of its SCF and hence, improve the ergodic channel capacity (ECC) of wireless communication systems. Accordingly, we present a method to find the optimum 3-D antenna array geometry for maximizing the ECC of a wireless communication system. This method develops a novel objective function to incorporate with a particle swarm optimization (PSO) for solving the resulting optimization problem. Simulation results are provided for confirming the validity and the effectiveness of the proposed method.
SPATIAL CORRELATION OF MULTIPLE ANTENNA ARRAYS IN WIRELESS COMMUNICATION SYSTEMS
2012-10-02
PIER
Vol. 132, 315-345, 2012
download: 143
Performance Analysis of Radar Target Recognition Using Natural Frequency: Frequency Domain Approach
Joon-Ho Lee Sung-Woo Cho Sang-Hong Park Kyung-Tae Kim
We consider the performance analysis of natural frequency-based radar target recognition in the frequency domain. Based on the probability density function (PDF) of some quantity consisting of the projections of the frequency response onto the column spaces of the matrices constructed using the natural frequencies of the specific targets, we propose to analytically calculate the probability of the correct classification, where the PDF is obtained from the inverse Fourier transform of the characteristic function. The scheme is validated by comparing the performance using the analytic method with that using the Monte-Carlo simulation.
PERFORMANCE ANALYSIS OF RADAR TARGET RECOGNITION USING NATURAL FREQUENCY: FREQUENCY DOMAIN APPROACH
2012-10-01
PIER
Vol. 132, 297-314, 2012
download: 104
Evaluation of the Zigbee Transmission Repetition Mechanism in the Variably-Loaded Reverberation Chamber
Kamil Staniec
The purpose of this paper is to provide both qualitative and quantitative assessment of one of the methods for providing reliable transmission in the ZigBee system. After intensive research on the time delay spread in a variably loaded reverberation chamber, this facility was then used to measure the Packet Error Rate under multipath conditions ranging from an unloaded to an overloaded chamber case. In all measurements, the key parameter was the number of allowed packet repetitions (retries). Eventually, recommendations were given regarding the optimal use of retries and their impact on ZigBee performance under different multipath scenarios obtained in the reverberation chamber and related to particular propagation environments to which these conditions are typical.
EVALUATION OF THE ZIGBEE TRANSMISSION REPETITION MECHANISM IN THE VARIABLY-LOADED REVERBERATION CHAMBER
2012-10-01
PIER
Vol. 132, 275-296, 2012
download: 188
Frequency Scanning Based Radar System
Yuri Alvarez-Lopez Cebrian Garcia-Gonzalez Carlos Vazquez-Antuna Samuel Ver-Hoeye Fernando Las Heras Andres
A novel imaging technique based on a frequency scanning antenna array is presented. The method is conceived to provide angular information in range-based radar systems which do not allow mechanical or electronic beam steering. The beam steering is changed with the frequency, which requires a novel scattered field data processing scheme/algorithm to recover the SAR image. System features, advantages and limitations are discussed, presenting simulation and measurement results which show the system capabilities to resolve the range and angular position of the objects.
FREQUENCY SCANNING BASED RADAR SYSTEM
2012-10-01
PIER
Vol. 132, 255-274, 2012
download: 120
Reducing the Power Consumption in Wireless Access Networks: Overview and Recommendations
Margot Deruyck Willem Vereecken Wout Joseph Bart Lannoo Mario Pickavet Luc Martens
Due to growing importance of wireless access and the steeply growing data volumes being transported, the power consumption of wireless access networks will become an important issue in the coming years. This paper presents a model for this power consumption and investigates three base station types: macrocell, microcell, and femtocell base stations. Based on these models, the coverage effectiveness of the three base station types is compared and the influence of some power reducing techniques such as sleep modes and MIMO (Multiple Input Multiple Output) is evaluated.
REDUCING THE POWER CONSUMPTION IN WIRELESS ACCESS NETWORKS: OVERVIEW AND RECOMMENDATIONS
2012-09-29
PIER
Vol. 132, 233-254, 2012
download: 41
Statistical Mid-Level Features for Building-Up Area Extraction from Full Polarimetric SAR Imagery
Wen Yang Ying Liu Gui-Song Xia Xin Xu
This paper addresses the problem of designing statistical features for the extraction of building-up areas (BAs) from highresolution polarimetric synthetic aperture radar (PolSAR) imagery. The idea is to represent a building-up area by the distribution of its mid-level components, called intermediates, which are statistical patterns unsupervisedly learnt from PolSAR images. More precisely, by analyzing the structural properties and the polarimetric characteristics exhibited in various terrain types, we propose two kinds of midlevel features for small regions: the cluster based statistical feature (CSF) and the scattering mechanism based statistical feature (SMSF). In detail, for the CSF, the intermediates are the K-mean clusters with Wishart distance of the PolSAR images; for the SMSF, the intermediates are the scattering mechanism categories obtained by relying on a four-component decomposition with deorientation of the PolSAR images. In contrast with existing features for describing BAs, the proposed features, i.e., CSF and SMSF, capture more complex context information of BAs. We compare the proposed features with those based on the Gaussian Markov random field (GMRF) models, which have been proven to be suitable for BAs mapping. Experimental results on RADARSAT-2 datasets demonstrate the effectiveness of the proposed features.
2012-09-27
PIER
Vol. 132, 215-232, 2012
download: 163
Sub-Millimeter Wave Frequency Scanning 8 X 1 Antenna Array
Rene Camblor-Diaz Samuel Ver-Hoeye Carlos Vazquez-Antuna George Roberto Hotopan Miguel Fernandez-Garcia Fernando Las Heras Andres
In this work, a sub-millimeter wave frequency scanning 8 x 1 element antenna array is presented for its use in a terahertz imaging system operating in the 220-330 GHz frequency band. The antenna array is formed by eight open ended waveguides, a phase-shifting network implemented with WR-3 rectangular waveguides and a power divider. Dielectric rods are used to improve the radiation patterns at large beam-steering angles. Prototypes of antenna arrays with and without the dielectric rods have been manufactured and experimentally characterized. A beam-steering range greater than 40° has been obtained for a frequency sweep between 270 GHz and 330 GHz.
SUB-MILLIMETER WAVE FREQUENCY SCANNING 8 x 1 ANTENNA ARRAY