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2011-03-15
PIER
Vol. 114, 481-493, 2011
download: 127
Eye-Shaped Segmented Reader Antenna for Near-Field UHF RFID Applications
Xiuping Li Jiankun Liao Yong Yuan Dan Yu
An eye-shaped segmented (ESS) antenna is presented for ultra-high frequency (UHF) near-field radio frequency identification (RFID) applications. The proposed antenna shows in-phase current even though the perimeter of the eye-shaped loop is comparable to the operating wavelength. The ESS antenna is fabricated on a FR4 printed circuit board (PCB) and embedded in a metal cavity with an overall size of 250×180×50 mm3. The measured bandwidth is around 11MHz (860-871 MHz) under the condition of VSWR less than 2.0, which covers the Europe standard (865MHz-868MHz) and agrees well with the simulated results. Finally, as a reader antenna in the RFID system, the measured read distance and read width can achieve 16.1 cm and 8 cm, respectively. The ESS antenna is desirable for UHF near-field RFID reader applications.
EYE-SHAPED SEGMENTED READER ANTENNA FOR NEAR-FIELD UHF RFID APPLICATIONS
2011-03-14
PIER
Vol. 114, 469-479, 2011
download: 200
Detection of Gas Concentration by Correlation Spectroscopy Using a Multi-Wavelength Fiber Laser
Binhao Wang Gabriel Somesfalean Liang Mei Haojiang Zhou Chunsheng Yan Sailing He
A correlation spectroscopy (COSPEC) based on a multi-wavelength fiber laser is first proposed for the detection of gas concentration. The lasing wavelengths are selected to match several characteristic absorption peaks of the gas under test, and the gas concentration is easily measured by correlating it with the reference gas. The present method is immune from the instability of the light source and the influence of other gases. The concentration measurement of C2H2 is demonstrated in the experiment in its near-infrared dominant absorption region. The technique has prospects for simultaneous detection of multiple gases, and the measurement of mixed gases of C2H2 and CO2 is also analyzed.
DETECTION OF GAS CONCENTRATION BY CORRELATION SPECTROSCOPY USING A MULTI-WAVELENGTH FIBER LASER
2011-03-12
PIER
Vol. 114, 457-468, 2011
download: 115
Design and Fabrication of a Quad-Band Bandpass Filter Using Multi-Layered SIR Structure
Ru-Yuan Yang Cheng-Yuan Hung Jia-Sheng Lin
In this paper, design and fabrication of a quad-band microstrip bandpass filter (BPF) using multi-layered stepped impedance resonators (SIRs) structure is proposed. One pair of SIR on the top layer is designed to operate at the 1st and 3rd passbands (1.56/3.57 GHz), and the other pair is at 2nd and 4th passbands (2.42/5.23 GHz) by tuning the impedance and length ratios of the SIRs. In order to find the desired coupling location between the SIRs located on different layers and the input/output (I/O) lines, the voltage, current and power wave on the I/O lines are analyzed. It is verified that the proposed quad-band filter has good passband performances with an excellent isolation between adjacent bands for GPS, WLAN, and WiMAX applications.
DESIGN AND FABRICATION OF A QUAD-BAND BANDPASS FILTER USING MULTI-LAYERED SIR STRUCTURE
2011-03-12
PIER
Vol. 114, 443-455, 2011
download: 939
An Exact Solution of the Cylindrical Wave Equation for Electromagnetic Field in Fractional Dimensional Space
Muhammad Zubair Muhammad Junaid Mughal Qaisar Naqvi
This work deals with an exact solution of cylindrical wave equation for electromagnetic field in fractional dimensional space. The obtained fractional solution is a generalization of the cylindrical wave equation from integer dimensional space to a fractional dimensional space. The resulting theoretical framework can be used to study the phenomenon of electromagnetic wave propagation in any fractal media because fractal media can be described as an ordinary media in a fractional dimensional space. The classical results are recovered from fractional solution when integer dimensional space is considered.
AN EXACT SOLUTION OF THE CYLINDRICAL WAVE EQUATION FOR ELECTROMAGNETIC FIELD IN FRACTIONAL DIMENSIONAL SPACE
2011-03-10
PIER
Vol. 114, 429-441, 2011
download: 117
Subwavelength Array of Planar Triangle Monopoles with Cross Slots Based on Far-Field Time Reversal
Guang-Ding Ge Duo Wang Bing-Zhong Wang
A subwavelength array of planar triangle monopole antennas is proposed and discussed in this paper. Each element of the array is etched with many cross slots which bring no effects to the element's performances of voltage standing wave ratio and far-field radiation patterns. An important property of this antenna is that if multiple such planar antennas are placed face to face, the proposed array can perform time-reversal far-field focusing with a super-resolution as small as one twentieth of a wavelength. The proposed subwavelength array is easy to design and convenient for integration.
SUBWAVELENGTH ARRAY OF PLANAR TRIANGLE MONOPOLES WITH CROSS SLOTS BASED ON FAR-FIELD TIME REVERSAL
2011-03-10
PIER
Vol. 114, 407-428, 2011
download: 171
Extension of Winding Function Theory for Radial and Axial Nonuniform Air Gap in Salient Pole Synchronous Machines
Hamidreza Akbari H. Meshgin-Kelk Jafar Milimonfared
In this paper, to calculate the salient pole machine inductances under radial and axial non-uniformity, a new method is developed. The method, an extension of the modified winding function theory to 3D, allows studying salient pole machines with radial and axial non-uniform air gap considering more realistic mean radius of the air gap. By using the developed method and a precise geometrical model, inductances of a salient pole machine with inclined rotor are calculated. Inductances are evaluated and effects of several asymmetries on inductances are shown. Calculated inductances are used in a coupled electromagnetic model, for simulation of a salient pole machine under healthy and different inclined eccentricity conditions. Simulation results show that the 19th stator current harmonic can be detected to alarm for inclined rotors. Experimental results that validate the theoretical and simulation results are presented.
EXTENSION OF WINDING FUNCTION THEORY FOR RADIAL AND AXIAL NONUNIFORM AIR GAP IN SALIENT POLE SYNCHRONOUS MACHINES
2011-03-08
PIER
Vol. 114, 395-405, 2011
download: 122
Quasi-Elliptic Function Bandpass Filter with Upper Stopband Extension and High Rejection Level Using Cross-Coupled Stepped-Impedance Resonators
Jen-Tsai Kuo Shao-Chan Tang Shu-Hsien Lin
Planar microstrip filters are designed to have a quasi-elliptic function passband and extended upper stopband with a rejection level of 40 or 50 dB. The design employs stepped-impedance resonators in a compact 2×2 cross coupled configuration. The geometric parameters of the resonators are planned to shift the third resonance as high as possible, and then the transmission zeros created by the structure are devised to suppress the second resonance, so that a wide upper stopband up to more than 4.5 times the passband frequency can be achieved. By employing the skew-symmetric input/output feeds, three transmission zeros in the frequency band of interest can be created. The leading two zeros are allocated on the both sides of the passband, generating a quasi-elliptic function response with enhanced roll-off rate in the transition bands, and the last zero incorporating with a zero created by anti-coupled-line at higher frequencies are employed to extend the rejection bandwidth. The measurement data agree very well with the simulation responses.
QUASI-ELLIPTIC FUNCTION BANDPASS FILTER WITH UPPER STOPBAND EXTENSION AND HIGH REJECTION LEVEL USING CROSS-COUPLED STEPPED-IMPEDANCE RESONATORS
2011-03-05
PIER
Vol. 114, 383-393, 2011
download: 147
Seven Ports Power Divider with Various Power Division Ratios
Ayman Sulaiman Al-Zayed Samir Mahmoud
A seven ports network is proposed to act as a six-way power divider/combiner. The proposed network structure consists of a set of λ/4 planar transmission lines at the design frequency and does not require any isolating resistor. The power divider is capable of providing various power ratios by judicious choice of the transmission lines characteristic impedances. Design equations are derived for arbitrary power ratios. Simulation results obtained from the ADS software proved the possibility of achieving preset power ratios with fairly linear phase response over a certain bandwidth. The latter depends on the chosen power ratios. Measured results of manufactured power dividers agree well with simulations and theory.
SEVEN PORTS POWER DIVIDER WITH VARIOUS POWER DIVISION RATIOS
2011-04-04
PIER
Vol. 114, 369-381, 2011
download: 103
Empirical Miniaturization Analysis of Inverse Parabolic Step Sequence Based UWB Antennas
Rashid Saleem Anthony Brown
In this paper we develop an empirical approach to the design of Ultra Wideband (UWB) antennas employing the Inverse Parabolic Step Sequence (IPSS). The relationships developed can be used to miniaturize the antenna and achieve a good impedance match over the UWB bandwidth. The overall aim of this process is to give a good starting point for detailed numerical optimizations. We will illustrate the use of these formulae in three different designs of IPSS-based antennas. A low loss duroid substrate of loss tangent, tan δ, 0.0009, relative permittivity 2.2 and thickness 1.575 mm is used to simulate these planar monopole antennas in Ansoft High Frequency Structure Simulator (HFSS).
EMPIRICAL MINIATURIZATION ANALYSIS OF INVERSE PARABOLIC STEP SEQUENCE BASED UWB ANTENNAS
2011-04-04
PIER
Vol. 114, 353-368, 2011
download: 142
A Four-Parameter m -Profile Model for the Evaporation Duct Estimation from Radar Clutter
Jin-Peng Zhang Zhen-Sen Wu Qing-Lin Zhu Bo Wang
A new four-parameter modified refractivity profile (M-profile) model for the evaporation duct is introduced in this paper. In the estimation of radio refractivity structure from sea clutters, a parametric M-profile model is normally employed. The conventional M-profile model for evaporation ducts is the one-parameter log linear model, which has some potential disadvantages in describing the observed M-profiles which would result in rough results of evaporation duct estimation. Based on this model, three new parameters are introduced and a four-parameter M-profile model is proposed here. This model has the ability to (a) more accurately match real-world M-profiles, (b) well replicate the observed clutter field, and (c) show clutter power or path loss sensitivity to each model parameter. All these abilities are necessary for robust refractivity estimations. The performance of this model is tested and validated through the estimation for two truly measured M-profiles.
A FOUR-PARAMETER M-PROFILE MODEL FOR THE EVAPORATION DUCT ESTIMATION FROM RADAR CLUTTER
2011-03-03
PIER
Vol. 114, 333-352, 2011
download: 139
A High Order Integral SPM for the Conducting Rough Surface Scattering with the Tapered Wave Incidence-TE Case
Li-Xin Guo Yu Liang Jie Li Zhen-Sen Wu
Based on the Helmholtz integral equation and series expansion theory, a high order integral small perturbation method (HISPM) for studying electromagnetic wave scattering from the finite conducting rough surface with tapered transverse electric (TE) wave incidence is presented. The high order scattering coefficients are obtained by the series expansion, the validity and accuracy of HISPM is verified through numerical evaluation with classical small perturbation method (CSPM) and the method of moments (MOM). By comparing with CSPM for the infinite rough surface case with plane wave incidence, the presented HISPM can greatly reduce the edge diffraction effect. HISPM also shows advantages in the memory requirement and computational time, especially in calculating scattering coefficients with low grazing angle incidence. Numerical examples are given to show that with the increasing of the length of the rough surface, the memory requirements and the computation time of HISPM are dramatically reduced compared to those of MOM.
A HIGH ORDER INTEGRAL SPM FOR THE CONDUCTING ROUGH SURFACE SCATTERING WITH THE TAPERED WAVE INCIDENCE-TE CASE
2011-03-02
PIER
Vol. 114, 317-332, 2011
download: 114
Pulsed Beam Expansion of Electromagnetic Aperture Fields
Timor Melamed
The present contribution is concerned with an exact frame-based pulsed-beams expansion of planar aperture time-dependent electromagnetic fields. The propagating field is described as a discrete superposition of tilted, shifted and delayed electromagnetic pulsed-beam waveobjects over the frame spectral lattice. Explicit asymptotic expressions for the electromagnetic pulsed-beam propagators are obtained for the commonly used pulsed-quadratic windows.
PULSED BEAM EXPANSION OF ELECTROMAGNETIC APERTURE FIELDS
2011-03-02
PIER
Vol. 114, 301-315, 2011
download: 110
An Efficient Hybrid Technique for Analysis of the Electromagnetic Field Distribution Inside a Closed Environment
Viet Phuong Bui Xing-Chang Wei Er Ping Li Wei-Jiang Zhao
This paper presents an efficient hybrid simulation technique for analysis of the electromagnetic field interactions between multi-transmitters and receivers located within a closed environment. The Method of Moments/circuit method is first used for modeling of the transceivers and their nearby surrounding to obtain the equivalent sources/receivers. Then, an approach that combines the asymptotic method and the ray tracing technique is deployed to calculate the long-distance coupling between a pair of transmitter and receiver. The acceleration algorithms for ray tracing have been developed to deal with more complex scenarios. The seamless combination between the circuit, numerical, and asymptotic approaches is the key to get accurate simulation results. Several numerical examples and experimental results are presented to demonstrate the efficiency of the proposed technique.
AN EFFICIENT HYBRID TECHNIQUE FOR ANALYSIS OF THE ELECTROMAGNETIC FIELD DISTRIBUTION INSIDE A CLOSED ENVIRONMENT
2011-03-02
PIER
Vol. 114, 285-299, 2011
download: 124
Model Order Reduction for Peec Modeling Based on Moment Matching
Zhenfei Song Donglin Su Fabrice Duval Anne Louis
Accurate and effective system-level modeling has become necessary to address electromagnetic compatibility (EMC) issues in modern circuit and system design. Model order reduction (MOR) techniques provide a feasibility to approximate complex circuit models with compact reduced-order models. In this paper, an effective MOR technique entitled multi-point moment matching (MMM) is implemented for the partial element equivalent circuit (PEEC) modeling. Moment information at multiple frequency points is used in this method in order to accurately estimate a given system over an entire frequency range of interest, and for each frequency an enhanced asymptotic waveform evaluation (AWE) is applied to obtain a reduced-order model by constructing a pole-residue representation of the original transfer function. The improvements of conventional AWE in aspects of both moment computation and moment matching can avoid ill-conditioned moment matrices and unstable dominant poles. The complex frequency hopping (CFH) technique is employed to select the multiple expansion points by using a newly developed upwardsearch algorithm. Numerical simulations of coupled microstrip lines in both frequency and time domain indicate the effectiveness of the proposed method.
MODEL ORDER REDUCTION FOR PEEC MODELING BASED ON MOMENT MATCHING
2011-03-01
PIER
Vol. 114, 271-283, 2011
download: 135
Tunable Photonic Band Gap in a Doped Semiconductor Photonic Crystal in Near Infrared Region
Chien-Jang Wu Ya-Chang Hsieh Heng-Tung Hsu
In this work, we theoretically investigate the tunable photonic band gap (PBG) in a semiconductor-dielectric photonic crystal made of highly doped n-type silicon (Si) layers alternating with silicon oxide layers. The tunable characteristic is studied by changing the donor impurity concentration in Si layer. The PBG is numerically analyzed in the near infrared frequency region from the reflectance calculated by the transfer matrix method. The effect of filling factor in Si layer on the photonic band gap is also illustrated. These tunable properties in such a photonic crystal provide some information that could be of technical use to the semiconductor optoelectronics, especially in communication applications.
TUNABLE PHOTONIC BAND GAP IN A DOPED SEMICONDUCTOR PHOTONIC CRYSTAL IN NEAR INFRARED REGION
2011-03-01
PIER
Vol. 114, 255-269, 2011
download: 196
Differential Electromagnetic Equations in Fractional Space
Muhammad Zubair Muhammad Junaid Mughal Qaisar Naqvi Azhar Abbas Rizvi
The present study deals with a novel approach for fractional space generalization of the differential electromagnetic equations. These equations can describe the behavior of electric and magnetic fields in any fractal media. A new form of vector differential operator Del, and its related differential operators, is formulated in fractional space. Using these modified vector differential operators, the classical Maxwell equations have been worked out for fractal media. The Laplace, Poisson and Helmholtz equations in fractional space are derived by using modified vector differential operators. Also a new fractional space generalization of the potentials for static and time varying fields is presented.
2011-03-01
PIER
Vol. 114, 235-254, 2011
download: 114
Low-Frequency Excitation of Leaky Modes in a Microstrip Line with a Top Cover
Joaquin Bernal Mendez Francisco Mesa David Richard Jackson
This paper studies the excitation of a physical leaky mode in a covered microstrip structure at low frequencies. We calculate the current excited in the line by a delta-gap voltage source via a full wave analysis based on a mixed potential integral equation scheme. The current in the line is decomposed into its bound mode and continuous spectrum components. The bound mode component is associated with the propagation effects whereas the continuous spectrum component is associated with reactive and/or radiative effects and contains the contribution of the leaky mode. Our analysis also includes a detail study of the dispersion relations of the bound and leaky modes along with their corresponding electric fields. At low frequencies, in the covered microstrip structure with a low top cover height, we have found that the bound mode role is superseded by the leaky mode, in the sense that it is the leaky mode which partially or totally carries the signal energy. Therefore, the spurious effects associated with the excitation of a leaky mode, which usually appear at high frequencies in open microstrip lines, appear here in the low frequency range. This effect may have very relevant practical consequences in the performance of such systems.
LOW-FREQUENCY EXCITATION OF LEAKY MODES IN A MICROSTRIP LINE WITH A TOP COVER
2011-03-01
PIER
Vol. 114, 211-234, 2011
download: 190
Insulation Fault Diagnosis in High Voltage Power Transformers by Means of Leakage Flux Analysis
Manes Fernandez Cabanas Francisco Pedrayes González Manuel García Melero Carlos H. Rojas García Gonzalo Alonso Orcajo José Manuel Cano Rodríguez Joaquín González Norniella
Power transformers in service are subjected to a wide variety of electrical, mechanical and thermal stresses capable of producing insulation faults. This type of failure figures amongst the most costly faults in distribution networks since it produces both machine outage and electrical supply interruption. Major research effort has therefore focused on the early detection of faults in the insulating systems of large high voltage power transformers. Although several industrial methods exist for the on-line and off-line monitoring of power transformers, all of them are expensive and complex, and require the use of specific electronic instrumentation. For these reasons, this paper will present the On-Line analysis of transformer leakage flux as an efficient alternative for assessing machine integrity and detecting the presence of insulating failures during their earliest stages. An industrial 400 kVA-20 kV/400V transformer will be used for the experimental study. Very cheap, simple sensors, based on air core coils, will be used to measure the leakage flux of the transformer, and non-destructive tests will also be applied to the machine in order to analyse pre- and post-failure voltages induced in the coils.
INSULATION FAULT DIAGNOSIS IN HIGH VOLTAGE POWER TRANSFORMERS BY MEANS OF LEAKAGE FLUX ANALYSIS
2011-02-28
PIER
Vol. 114, 195-210, 2011
download: 147
Spatial Microwave Power Combining with Anisotropic Metamaterials
Bo Wang Ka-Ma Huang
This paper proposes a novel approach for the spatial microwave power combining. Anisotropic metamatierials are employed to trim the combined electrical fields and form a single beam radiation pattern. The radiation characteristics of a binary horn antennas array are investigated both numerically and experimentally at 12 GHz. The results show that much higher combining efficiency can be achieved. Given a designed combining efficiency, the strict relative position requirements in each transmission unit are reduced in this scheme.
SPATIAL MICROWAVE POWER COMBINING WITH ANISOTROPIC METAMATERIALS
2011-02-25
PIER
Vol. 114, 177-194, 2011
download: 172
Diagonal Horn Gaussian Efficiency Enhancement by Dielectric Loading for Submillimeter Wave Application at 150 GHz
Ou Xu
The dielectric pyramid loaded and the dielectric cone loaded diagonal horn working at 150 GHz are investigated by using Gaussian beam mode analysis. With extremely low cross-polarized and axially symmetrical field distribution in the horn aperture, the calculated fundamental Gaussian mode coupling achieves about 98%. The far field radiation patterns of the two antennas are analyzed using fundamental Gaussian mode aperture-field distribution model whose results agree with high-accuracy CSTTM software computations, indicating that the dielectric loaded horns radiate fine Gaussian beams. The dielectric loaded geometry may be used to modify the diagonal horns with distorted beam.
DIAGONAL HORN GAUSSIAN EFFICIENCY ENHANCEMENT BY DIELECTRIC LOADING FOR SUBMILLIMETER WAVE APPLICATION AT 150 GHz