Vol. 54
Latest Volume
All Volumes
PIER 180 [2024] PIER 179 [2024] PIER 178 [2023] PIER 177 [2023] 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]
2005-04-18
PIER
Vol. 54, 321-333, 2005
download: 287
Electromagnetic Wave Equation in Differential-Form Representation
Ismo Veikko Lindell
Differential-form formalism has been often applied, in stead of the more commonplace Gibbsian vector calculus, to express the basic electromagnetic equations in simple and elegant form. However, representing higher-order equations has met with unexpected difficulties, in particular, when dealing with general linear electromagnetic media. In the present study, wave equations involving scalar operators of the fourth order are derived for the electromagnetic two-form and the potential one-form, for the general linear bi-anisotropic medium. This generalizes previous coordinate- free approaches valid for certain special classes of media. The analysis is based on some multivector and dyadic identities derived in the Appendix.
2005-04-18
PIER
Vol. 54, 303-319, 2005
download: 276
A Unique Solution to the 2-d h -Scattering Problem for a Semicircular Trough in a PEC Ground Plane
Alexander Tyzhnenko
A rigorous solution to the Neumann boundary value problem (BVP) for semicircular trough in a perfectly electrically conducting (PEC) ground plane is presented. The known Rayleigh's method expansion of a solution by eigensolutions of the Helmholtz equation in cylindrical coordinates coupled with partial orthogonality of trigonometric functions is used. In contrast to previous works on this theme, a Fredholm 2nd kind matrix equation for modal coefficients is obtained, which permits one to derive very fast convergent approximate solution for any incidence angle and trough dimension. The method solution permits one to consider a dielectric loading as well. A strong broadband fall-off of backscattering from apertures loaded with lossy dielectric is theoretically revealed.
A UNIQUE SOLUTION TO THE 2-D H-SCATTERING PROBLEM FOR A SEMICIRCULAR TROUGH IN A PEC GROUND PLANE
2005-04-18
PIER
Vol. 54, 283-302, 2005
download: 237
An Innovative Fuzzy-Logic-Based Strategy for an Effective Exploitation of Noisy Inverse Scattering Data
Renzo Azaro , Aronne Casagranda , Davide Franceschini and Andrea Massa
This paper presents an innovative inverse scattering approach based on a fuzzy-logic strategy aimed at fully exploiting the information content of the scattered data in a microwave imaging system. The effectiveness of the proposed method is assessed through the results of a numerical analysis concerned with the reconstruction of single as well as multiple dielectric targets in various noisy environments. For comparison purposes, the obtained performance are compared with those of a standard method in terms of reconstruction accuracy and computational load to point out the improvement induced by the proposed approach.
AN INNOVATIVE FUZZY-LOGIC-BASED STRATEGY FOR AN EFFECTIVE EXPLOITATION OF NOISY INVERSE SCATTERING DATA
2005-04-18
PIER
Vol. 54, 263-281, 2005
download: 244
Non-Relativistic Scattering: Pulsating Interfaces
Dan Censor
Scattering by pulsating objects is discussed. In the case of the pulsating cylinder, its surface vibrates time-harmonically in the radial direction. The formalism is based on first-order v/c relativistic approximations, and on the assumption that the ambient media are not affected by the mechanical motion of the interface. This is conducive to simpler and amenable approximations. The cases analyzed display the modulation effect due to the mechanical motion at frequency Ω, creating new spectral components in the scattered wave, peaking at the sideband frequencies ωex ± nΩ around the excitation frequency. To put such phenomena in a quasi-relativistic and electromagnetic context, and account for the boundary-condition problem and the representation of the scattered wave is the subject of the present investigation. Such effects can be used to remotely sense the properties of the scatterer, especially its motion.
2005-04-18
PIER
Vol. 54, 245-262, 2005
download: 383
Application of Integral Equation Method to Metal-Plate Lens Structures
Akira Matsushima , Y. Nakamura and S. Tomino
The present paper concerns the design, numerical analysis, and measurement for simple metal-plate lens structures. The power of electromagnetic waves can be concentrated by arranging flat strips parallel to one another and adjusting the transverse and longitudinal length of the waveguide regions. The simple designing procedures are described for the lenses with plane, concave, and convex profiles. These steps are practically applied to construct the lenses for the X band. In order to discuss the dependence of focusing properties on the lens and source types, we numerically analyze the scattering problems using the integral equations combined with the moment method. The lenses are made up by aluminum plates, and the field amplitude in the transmission region is measured. We confirm the formation of the focus near the design point.
APPLICATION OF INTEGRAL EQUATION METHOD TO METAL-PLATE LENS STRUCTURES
2005-04-18
PIER
Vol. 54, 221-244, 2005
download: 276
Electromagnetci Field from a Horizontal Electric Dipole in the Spherical Electrically Earth Coated with n -Layered Dielectrics
Kai Li and Yi-Long Lu
In this paper, the electromagnetic field in air from a radiating horizontal electric dipole located in the homogeneous isotropic spherical electrically earth coated with N-layered dielectrics is investigated anew. The starting point is based on the formulas for the electromagnetic fields in air from vertical electric and magnetic dipoles situated in air above the surface of the earth coated with N-layered dielectrics. The complete explicit formulas are derived for the electromagnetic fields in the earth due to vertical electric and magnetic dipoles located in air. By using reciprocity theorem, the formulas are readily obtained for the six components of the electromagnetic field in air radiated by a horizontal electric dipole located in the earth.
ELECTROMAGNETCI FIELD FROM A HORIZONTAL ELECTRIC DIPOLE IN THE SPHERICAL ELECTRICALLY EARTH COATED WITH N-LAYERED DIELECTRICS
2005-04-18
PIER
Vol. 54, 199-220, 2005
download: 247
Depolarized Upward and Downward Multiple Scattering from a Very Rough Surface
Chin-Yuan Hsieh and Adrian Fung
From a very roughly random surface the backscattering enhancement is predicted due to the constructive interference of multiple surfaces scattering. For specialized surfaces involving roughness large compared with the incident wavelength, the backscattering enhancement takes place. The phenomenon of backscatter enhancement becomes evident for both larger normalized surface height and surface rms slope. In this paper we take further study to predict the backscattering enhancement mainly comes from upward multiple scattering. On the contrary the downward multiple scattering has no contributions to the scatter strength of backscattering enhancement. The model developed in this paper is based upon the integral equation method and able to predict this phenomenon of multiple scattering and backscattering enhancement. The depolarized multiple scattering makes much contribution along the plane of incidence from random rough surfaces, but depolarized single scattering makes little contributions. The total multiple scattering strength is the summation of upward and downward multiple scattering strength. In comparison of model prediction of total multiple scattering strength with measured data along the specular plane, excellent agreement is obtained.
DEPOLARIZED UPWARD AND DOWNWARD MULTIPLE SCATTERING FROM A VERY ROUGH SURFACE
2005-04-18
PIER
Vol. 54, 179-198, 2005
download: 324
Reconstruction of Equivalent Currents Using a Near-Field Data Transformation - with Radome Applications
Kristin Persson and Mats Gustafsson
Knowledge of the current distribution on a radome can be used to improve radome design, detect manufacturing errors, and to verify numerical simulations. In this paper, the transformation from near-field data to its equivalent current distribution on a surface of arbitrary material, i.e., the radome, is analyzed. The transformation is based on the scalar surface integral representation that relates the equivalent currents to the near-field data. The presence of axial symmetry enables usage of the fast Fourier transform (FFT) to reduce the computational complexity. Furthermore, the problem is regularized using the singular value decomposition (SVD). Both synthetic and measured data are used to verify the method. The quantity of data is large since the height of the radome corresponds to 29-43 wavelengths in the frequency interval 8.0-12.0 GHz. It is shown that the method gives an accurate description of the field radiated from an antenna, on a surface enclosing it. Moreover, disturbances introduced by copper plates attached to the radome surface, not localized in the measured near field, are focused and detectable in the equivalent currents.
RECONSTRUCTION OF EQUIVALENT CURRENTS USING A NEAR-FIELD DATA TRANSFORMATION - WITH RADOME APPLICATIONS
2005-02-18
PIER
Vol. 54, 155-178, 2005
download: 295
FDTD Analysis of a Dual-Frequency Microstrip Patch Antenna
Steven Gao , Joshua Le-Wei Li and A. Sambell
Characteristics of a single-layer, dual-frequency microstrip patch antenna, which uses a T-strip loaded rectangular microstrip patch, are studied. This antenna is easy to achieve good impedance matching at both frequencies by tuning the feed position and other design parameters. Another advantageous aspect is that it has high polarization purity. A detailed parameter study is performed and the theoretical analysis is based on the finite-difference time-domain (FDTD) method. The FDTD programs are developed and validated by measurement results. The effects of various antenna parameters on two resonant frequencies, frequency ratio, and radiation pattern characteristics of the antenna are analyzed and discussed. It is shown that various frequency ratios (1.5-2.49) can be obtained by varying the design parameters of this antenna. Similar radiation patterns with same polarization are obtained at two resonant frequencies. Several design curves are presented.
FDTD ANALYSIS OF A DUAL-FREQUENCY MICROSTRIP PATCH ANTENNA
2005-02-17
PIER
Vol. 54, 137-154, 2005
download: 248
Effective Exploitation of Multi-View Data through the Iterative Multi-Scaling Method - an Experimental Assessment
Massimo Donelli , Davide Franceschini , Gabriele Franceschini and Andrea Massa
The reconstruction capabilities of a microwave imaging algorithm can be enhanced by exploiting a multi-view measurement set-up. In the past, different researches have proved that collecting scattering data by probing the unknown scenario from different incidence angles, it allows to acquire more information on the scenario under test. This paper is aimed at verifying such an assumption in a real scenario when the Iterative Multi-Scaling Approach (IMSA) is used to fully exploit multi-view data. In fact, unlike synthetic data, in a real environment more measurements introduce larger systematic errors that could affect the physical constraints used in the inversion procedure and, consequently, the reconstruction process. Thus, the analysis is carried out by considering a set of experimental data concerning different scattering configurations involving single and multiple dielectric scatterers.
EFFECTIVE EXPLOITATION OF MULTI-VIEW DATA THROUGH THE ITERATIVE MULTI-SCALING METHOD - AN EXPERIMENTAL ASSESSMENT
2005-02-17
PIER
Vol. 54, 109-135, 2005
download: 227
Use of Semi-Inversion Method for the Dirichlet Problem in Rough Surface Scattering
V. Tatarskii
The scattering problem from the random interface with the Dirichlet boundary condition can be formulated as an integral equation x = K̂y with respect to surface sources y (here, K̂ is the integral operator). Starting with an approximate operator K̂0, for which the inverse operator M̂=K̂−10 is known, the series in powers of the operator Ẑ=M̂(K̂0−K̂) is derived. As an approximate kernel, we consider the kernel depending only on the difference of arguments: K0=K0(r-r´), for which the kernel of the operator M̂ can be found in terms of generalized functions. The norm of the difference operator ||Ẑ|| is found; the conditions of convergency ||Ẑ||≤ 1 were obtained.
USE OF SEMI-INVERSION METHOD FOR THE DIRICHLET PROBLEM IN ROUGH SURFACE SCATTERING
2005-02-17
PIER
Vol. 54, 95-108, 2005
download: 228
Soliton-Soliton Interaction with Power Law Nonlinearity
Swapan Konar and Anjan Biswas
The intra-channel collision of optical solitons, with power law nonlinearity, is studied in this paper with the aid of quasi-particle theory. The perturbation terms that are considered in this paper are of Hamiltonian type. The suppression of soliton-soliton interaction, in presence of these perturbation terms, is achieved. The numerical simulations support the quasi-particle theory.
SOLITON-SOLITON INTERACTION WITH POWER LAW NONLINEARITY
2005-02-17
PIER
Vol. 54, 83-93, 2005
download: 475
A Novel Microstrip Patch Antenna with Large Impedance Bandwidth in VHF/UHF Rang
Tapas Chakravarty , Sushim Roy , Salil Sanyal and Asok De
In this paper a novel antenna is presented. This antenna, employing microstrip circular disc as radiator is seen to perform over a large impedance bandwidth (130 MHz to 876 MHz). The disk resonator is loaded with L-C-R circuit across a selective location in the disk via a thin shorting pin. The theoretical modeling predicts TM01 mode of operation. Therefore the beam pattern shows a null in the broadside direction. The said antenna is proposed to be developed for end use in coal mine where the antenna can be flush mounted on coal strata. Thus it will be able to measure the angle of arrival of any reflective component due to presence of waterbed at a distance. The measured as well as simulated results regarding impedance bandwidth and beam pattern agrees well. The simulated efficiency using IE3D is 48% whereas measured efficiency is nearly 45%.
A NOVEL MICROSTRIP PATCH ANTENNA WITH LARGE IMPEDANCE BANDWIDTH IN VHF/UHF RANG
2005-02-17
PIER
Vol. 54, 61-81, 2005
download: 426
Artificial Magnetic Materials Based on the New Magnetic Particle: Metasolenoid
Stanislav I. Maslovski , Pekka M. T. Ikonen , Igor Kolmakov , Sergei Tretyakov and Mikko Kaunisto
New possibilities to design artificial magnetic materials for microwave frequencies are considered. Such composites can be used in microwave engineering at frequencies where no natural low-loss magnetic materials are available. A new magnetic particle (metasolenoid) formed by a stack of many parallel and very closely spaced single broken loops is proposed and analyzed analytically, numerically, and experimentally. It is shown that the effective permeability can reach reasonably high values over a wide frequency range when using such inclusions.
ARTIFICIAL MAGNETIC MATERIALS BASED ON THE NEW MAGNETIC PARTICLE: METASOLENOID
2005-02-17
PIER
Vol. 54, 37-59, 2005
download: 260
Fast Analysis of Electromagnetic Transmission through Arbitrarily Shaped Airborne Radomes Using Precorrected-FFT Method
Xiao-Chun Nie , Ning Yuan , Joshua Le-Wei Li , Tat Yeo and Yeow-Beng Gan
A fast technique based on the Poggio, Miller, Chang, Harrington and Wu (PMCHW) formulation and the precorrected-FFT method is presented for accurate and efficient analysis of electromagnetic transmission through dielectric radomes of arbitrary shape (including airborne radomes). The method of moments is applied to solve the integral equations in which the surfaces of the radomes are modeled using surface triangular patches and the integral equations are converted into a linear system in terms of the equivalent electric and magnetic surface currents. Next, the precorrected-FFT method, a fast approach associated with O(N 1.5 log N) or less complexity, is used to eliminate the requirement of generating and storing the square impedance matrix and to speed up the matrix-vector product in each iteration of the iterative solution. Numerical results are presented to validate the implementation and illustrate the accuracy of the method.
FAST ANALYSIS OF ELECTROMAGNETIC TRANSMISSION THROUGH ARBITRARILY SHAPED AIRBORNE RADOMES USING PRECORRECTED-FFT METHOD
2005-02-18
PIER
Vol. 54, 19-36, 2005
download: 329
Loaded Wire Antenna as EMI Sensor
Saswati Ghosh , Ajay Chakraborty and Subrata Sanyal
This paper describes the performance of different loaded wire antennas (e.g., inverted L, T, I and C-shaped antennas) as electromagnetic interference (EMI) sensors. Loaded wire antennas in transmitting mode are widely used for low frequency communication. However, while using these antennas as EMI sensors, the extra loading is likely to introduce the reception of cross-polarized component of incident electric field and investigation on this has not yet been performed. This paper highlights the results of the initial investigation on the performance of these loaded antennas as EMI sensors in terms of the Antenna Factor for the desired and cross-polarized component of incident electric field. The Method of Moments with Pulse basis function and Point-matching technique has been used to evaluate the current distribution on the antenna surface and hence the Antenna Factor.
LOADED WIRE ANTENNA AS EMI SENSOR
2005-02-18
PIER
Vol. 54, 1-17, 2005
download: 227
Edge-Preserving Regularization Scheme Applied to Modified Gradient Method to Reconstruct Two-Dimensional Targets from Data Laboratory-Controlled
Kamal Belkebir , Alexandre Baussard and Denis Premel
Abstract-In this paper, a two-dimensional inverse scattering problem dealing with microwave tomography is considered. To solve this non linear and ill-posed problem, an iterative scheme based on the Modified Gradient Method (MGM) is used. The object to be estimated is represented by a complex function, and some modifications of the MGM formulation have been considered. This algorithm leads to an efficient regularization scheme, based on edge preserving functions which act separately on the real and imaginary parts of the object. In order to show the interest of this regularized MGM, the algorithm is tested against laboratory-controlled microwave data.
EDGE-PRESERVING REGULARIZATION SCHEME APPLIED TO MODIFIED GRADIENT METHOD TO RECONSTRUCT TWO-DIMENSIONAL TARGETS FROM DATA LABORATORY-CONTROLLED