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2013-05-26
PIER
Vol. 139, 799-819, 2013
download: 134
Ultrasensitive Switching Between Resonant Reflection and Absorption in Periodic Gratings
Nikolay Komarevskiy Valery Shklover Leonid Braginsky Christian V. Hafner
Guided-Mode Resonance (GMR) effects in transparent periodic gratings possess a number of remarkable phenomena. GMRs exhibit strong features in the optical spectrum, i.e. dips, peaks, cusps, and may attain extremely high Q-factors. In some cases resonant reflection with the efficiency equal to unity can be observed. We demonstrate that the introduction of small losses in the structure can drastically modify its optical response by causing strong absorption resonances. Unity reflection in loss-free structures can be almost completely converted into unity absorption peaks as soon as very small losses are introduced. Even thin absorbing films in the structure (or in its vicinity) can lead to such strong resonant absorption effects. The resonances may exhibit a negligible spectral shift, but a significant variation in the magnitude when losses are slightly altered, which is highly attractive for sensor and switch applications. Absorption peaks experience a resonant behavior with respect to both frequency and material losses. We show that the width of the absorption peaks decreases and approaches the width of the reflection peaks, as losses decrease. Thus, high-Q resonances can be observed. The absorption resonances also possess strong angular dependence; they may split and significantly increase in magnitude for a slightly inclined incidence. We elucidate the resonant reflection/absorption effects theoretically and provide numerical examples.
ULTRASENSITIVE SWITCHING BETWEEN RESONANT REFLECTION AND ABSORPTION IN PERIODIC GRATINGS
2013-05-21
PIER
Vol. 139, 779-797, 2013
download: 196
Dual-Band Differential Filter Using Broadband Common-Mode Rejection Artificial Transmission Line
Armando Fernandez-Prieto Jesus Martel-Villagran Francisco Medina Francisco Mesa Shilong Qian Jia-Sheng Hong Jordi Naqui Ferran Martin
A new balanced dual-band bandpass filter with strong commonmode rejection is presented in this paper. Common-mode rejection is provided by a section of a periodic microstrip differential line that behaves as a low-pass filter under common-mode operation. In contrast, the differential line exhibits very good all-pass behavior under differential mode operation. This structure is combined with a differential dual-band bandpass filter based on embedded resonators. Simulations and experiments confirm that the combined structure has good common-mode rejection within the passbands of the dual-band differential filter.
DUAL-BAND DIFFERENTIAL FILTER USING BROADBAND COMMON-MODE REJECTION ARTIFICIAL TRANSMISSION LINE
2013-05-21
PIER
Vol. 139, 761-777, 2013
download: 139
Dual Fed Distributed Amplifier with Controlled Termination Adjustment
Narendra Kumar Ernesto Limiti Claudio Paoloni
A new circuit and technique to extend bandwidth performance while preserving improvement on efficiency performance over the one attainable by conventional distributed amplifier (DA) is presented. The theoretical analysis is described in detail, and a test vehicle is realized to demonstrate the effectiveness of the proposed method. Output power of ~29 dBm, gain of 10 dB, covering a bandwidth from 100 to 800 MHz, PAE of 20-45% is experimentally demonstrated. The result is compared with measured result of conventional DA, a significant improvement of bandwidth and efficiency are achieved.
DUAL FED DISTRIBUTED AMPLIFIER WITH CONTROLLED TERMINATION ADJUSTMENT
2013-05-19
PIER
Vol. 139, 743-759, 2013
download: 107
Multilevel Model Order Reduction with Generalized Compression of Boundaries for 3-D FEM Electromagnetic Analysis
Grzegorz Fotyga Krzysztof Nyka Michal Mrozowski
This paper presents a multilevel Model Order Reduction technique for a 3-D electromagnetic Finite Element Method analysis. The reduction process is carried out in a hierarchical way and involves several steps which are repeated at each level. This approach brings about versatility and allows one to efficiently analyze complex electromagnetic structures. In the proposed multilevel reduction the entire computational domain is covered with macro-elements which are subsequently nested, in such a way that size of the problem which has to be reduced at each level is relatively small. In order to increase the speed of the reduction at each level, the electric field at the macro-elements' boundaries is projected onto the subspace spanned by Legendre polynomials and trigonometric functions. The results of the numerical experiments confirm the validity and efficiency of the presented approach.
MULTILEVEL MODEL ORDER REDUCTION WITH GENERALIZED COMPRESSION OF BOUNDARIES FOR 3-D FEM ELECTROMAGNETIC ANALYSIS
2013-05-19
PIER
Vol. 139, 721-742, 2013
download: 136
CFAR Target Detection in Ground SAR Image Based on Kk Distribution
Yanzhao Gao Ronghui Zhan Jianwei Wan Jiemin Hu Jun Zhang
This paper deals with the problem of constant false alarm rate (CFAR) target detection in high-resolution ground synthetic aperture radar (SAR) images based on KK distribution. For the parameter estimation of KK distribution, the semi-experiential algorithm is analyzed firstly. Then a new estimation algorithm based on the particle swarm optimization (PSO) is proposed, which takes the discrepancies between the histogram of the clutter data and probability density function (PDF) of KK distribution at some selected points as the cost function to search for the optimal parameter values using PSO algorithm. The performance of the two algorithms is compared using Monte-Carlo simulation using the simulated data sets generated under different conditions; and the estimation results validate the better performance of the new algorithm. Then the KK distribution, which is proposed for spiky sea clutter originally, is applied to model the real ground SAR clutter data. The goodness-of-fit test clearly show that the KK distribution is able to model the ground SAR clutter much better than some common used model, such as standard K-distribution and Gamma, etc. On this basis, a global CFAR target detection algorithm is presented. The detection threshold is calculated numerically through the cumulative density function (CDF) of KK distribution. Comparing the amplitude of every SAR image pixel with this threshold, the potential targets in ground SAR images can be located effectively. Then target clustering is implemented to eliminate the false alarm and obtain more accurate target regions. The detection results of the proposed algorithm in a typical ground SAR image show that it has better performance than the detector based on G0 distribution.
CFAR TARGET DETECTION IN GROUND SAR IMAGE BASED ON KK DISTRIBUTION
2013-05-19
PIER
Vol. 139, 689-720, 2013
download: 138
Critical Model Components and Their Fingerprint Features in the Simulated Conducted Radio Frequency Immunity of Complex Integrated Circuits
Tao Su Yehua Yang Zixin Wang
To analyze and to handle the radio frequency immunity of microcontrollers requires understanding the origins of the complex frequency response of the immunity. This paper assumes that the frequency response of the immunity can be characterized with a set of fingerprint features in the immunity curves. Positions and shapes of those fingerprint features are determined by certain components in the disturbance propagation network. In order to prove that assumption, a series of models are created and simulated. The roles of various model components on the immunity are analyzed by comparing the simulation results from different model structures. The fingerprint features on the immunity curves are identified. The paper shows how to treat a wide-range immunity curve with separated features. It also shows the responsible model components for those separated features. With the awareness of those features and their origins, researchers can concentrate on extracting the models of the most important components in the disturbance propagation network when modeling the immunity of the complex integrated circuits like microcontrollers.
CRITICAL MODEL COMPONENTS AND THEIR FINGERPRINT FEATURES IN THE SIMULATED CONDUCTED RADIO FREQUENCY IMMUNITY OF COMPLEX INTEGRATED CIRCUITS
2013-05-19
PIER
Vol. 139, 671-687, 2013
download: 131
On-Road Magnetic Emissions Prediction of Electric Cars in Terms of Driving Dynamics Using Neural Networks
Ahmed Wefky Felipe Espinosa Frank Leferink Alfredo Gardel Robert Vogt-Ardatjew
This paper presents a novel artificial neural network (ANN) model estimating vehicle-level radiated magnetic emissions of an electric car as a function of the corresponding driving pattern. Real world electromagnetic interference (EMI) experiments have been realized in a semi-anechoic chamber using Renault Twizy. Time-domain electromagnetic interference (TDEMI) measurement techniques have been employed to record the radiated disturbances in the 150 kHz-30 MHz range. Interesting emissions have been found in the range 150 kHz-3.8 MHz approximately. The instantaneous vehicle speed and acceleration have been chosen to represent the vehicle operational modes. A comparative study of the prediction performance between different static and dynamic neural networks has been done. Results showed that a Multilayer Perceptron (MLP) model trained with extreme learning machines (ELM) has achieved the best prediction results. The proposed model has been used to estimate the radiated magnetic field levels of an urban trip carried out with a Think City electric car.
ON-ROAD MAGNETIC EMISSIONS PREDICTION OF ELECTRIC CARS IN TERMS OF DRIVING DYNAMICS USING NEURAL NETWORKS
2013-05-19
PIER
Vol. 139, 655-670, 2013
download: 248
Performance of FDTD Method Cpu Implementations for Simulation of Electromagnetic Processes
Dmitry L. Markovich Konstantin S. Ladutenko Pavel A. Belov
We analyze the performance of finite-difference time-domain (FDTD) method implementations for 2D and 3D problems. Implementations in Fortran, C and C++ (with Blitz++ library) languages and performance tests on several hardware setups (AMD, Intel i5, Intel Xeon) are considered. The performance of implementations using traditional FDTD algorithm for the largest size of test problem is limited by the bandwidth of computer random-accessed memory (RAM). Our implementations are compared with a commercial simulation software package Lumerical FDTD Solutions and an open source project Meep.
PERFORMANCE OF FDTD METHOD CPU IMPLEMENTATIONS FOR SIMULATION OF ELECTROMAGNETIC PROCESSES
2013-05-13
PIER
Vol. 139, 643-654, 2013
download: 118
Effects on the Energy Flux Density Due to Pitch in Twisted Clad Optical Fibers
Muhammad Abuzar Baqir Pankaj Choudhury
The paper deals with the propagation of electromagnetic waves through twisted clad dielectric optical fibers. The structure of these fibers is analogous to travelling wave tubes used in microwave devices, and the usefulness would be in the areas of optical sensing. This is because the twists in fiber would be affected due to the imposed stress and/or strain, leaving thereby the possibility to alter the propagation characteristics. A rigorous analytical investigation has been carried out with the emphasis on the energy flux density patterns due to the different propagating modes in the fiber. The dispersion relations of the system are deduced and the energy flux densities are evaluated under different pitch angles of twist. The effect due to conducting helix pitch on the electromagnetic wave propagation is emphasized.
EFFECTS ON THE ENERGY FLUX DENSITY DUE TO PITCH IN TWISTED CLAD OPTICAL FIBERS
2013-05-13
PIER
Vol. 139, 627-642, 2013
download: 127
Miniaturized Multilayer Dual-Mode Substrate Integrated Waveguide Filter with Multiple Transmission Zeros
Hong Xia Ziqiang Xu
A compact multilayer substrate integrated waveguide (SIW) dual-mode filter with multiple transmission zeros for high-selectivity application is presented. By introducing mixed coupling between source and load, the proposed filter could have four transmission zeros which can be controlled flexibly. Owing to the multilayer structure, the proposed filter occupies similar area in comparison with conventional dual-cavity dual mode SIW filters, but exhibits better frequency selectivity. An experimental filter with a center frequency of 10 GHz is designed using low temperature co-fired ceramic (LTCC) technology to validate the proposed structure, and measured results agree well with simulated ones.
MINIATURIZED MULTILAYER DUAL-MODE SUBSTRATE INTEGRATED WAVEGUIDE FILTER WITH MULTIPLE TRANSMISSION ZEROS
2013-05-13
PIER
Vol. 139, 611-626, 2013
download: 124
A New Conical-Trajectory Polar Format Algorithm for Spotlight Bistatic SAR
Yan Wang Jingwen Li Bing Sun Jie Chen Huaping Xu
The Polar Format Algorithm (PFA) is suitable for spotlight synthetic aperture radar (SAR) image focusing either in monostatic or bistatic cases. The classic linear-trajectory PFA complete data correction in wavenumber domain, converting data from the polar format to the rectangular format. However, the two-dimension processing (either using interpolation or chirp-z transform) introduces heavy computational load, which limits its real-time applications. This study presents a conical-trajectory PFA for bistatic SAR, in which the transmitter and receiver are designed to fly on conical surfaces, to simplify image formation procedures via eliminating the necessity of range processing. Moreover, the conical-trajectory PFA provides a space-invariant range resolution to simplify the SAR image comprehension. A spotlight forward-looking bistatic missile guidance application was simulated for the algorithm validation and performance analysis.
A NEW CONICAL-TRAJECTORY POLAR FORMAT ALGORITHM FOR SPOTLIGHT BISTATIC SAR
2013-05-13
PIER
Vol. 139, 599-610, 2013
download: 117
Pmm-GA Method to Synthesize Quasi-Optical Frequency Selective Surface on Sio2 Substrate
Bu Gang Xia Jin Meng De Hai Zhang Jin Sheng Zhang
A satellite-borne frequency selective surface (FSS) for atmospheric sensing application is presented. This brand new type of band-pass filter has an operating frequency at 183 GHz, which is a typical frequency on H2O absorption line. Comprising an ultra-thin gilding layer and a SiO2 substrate layer, this complex periodic component exhibits an extremely low insertion loss (< 0.22 dB) and high isolation (> 20 dB) between closely spaced frequency channels of 45° incident wave. Periodic Method of Moment (PMM) approach is applied to determine the initial geo-metrical parameters of FSS unit cell, and the optimization approach based on the Genetic Algorithm (GA) enables us to obtain the requisite spectral response and transmission characteristics for both TE and TM polarization. The experimental results show that the proposed PMM-GA technique is effective for analyzing space-borne FSS at millimeter wave range.
PMM-GA METHOD TO SYNTHESIZE QUASI-OPTICAL FREQUENCY SELECTIVE SURFACE ON SiO<sub>2</sub> SUBSTRATE
2013-05-10
PIER
Vol. 139, 577-597, 2013
download: 110
Implementation and Application of the Spherical MRTD Algorithm
Yawen Liu Yi-Wang Chen Pin Zhang Xin Xu
This paper illustrates an explicit multiresolution time-domain (MRTD) scheme based on Daubechies' scaling functions with a spherical grid for time-domain Maxwell's equations. The stability and dispersion property of the scheme are investigated and it is shown that larger cells decrease the numerical phase error, which makes it significantly lower than FDTD for low and medium discretizations. Moreover, this technique is applied to the modeling of an air-filled spherical resonator, and numerical results demonstrate the effectiveness of the proposed algorithm.
IMPLEMENTATION AND APPLICATION OF THE SPHERICAL MRTD ALGORITHM
2013-05-09
PIER
Vol. 139, 559-575, 2013
download: 140
A Hybrid Computer-Aided Tuning Method for Microwave Filters
Yong-Liang Zhang Tao Su Zhi-Peng Li Chang-Hong Liang
A hybrid tuning method for microwave filters is presented in this paper. This novel tuning technique is based on the combination of the Cauchy method and aggressive space mapping (ASM) technique. Cauchy method is applied to determine the characteristic polynomials of the filter's response, then the parameters (coupling matrix) of the low-pass prototype is extracted from the characteristic polynomials. The aggressive space mapping is used to optimized the fine model to guarantee that each step of a tuning is always in the right direction. The validity is verified by two examples. One deals with the four-resonator cross-coupled filter and the other one is an direct coupled six-resonator filter.
A HYBRID COMPUTER-AIDED TUNING METHOD FOR MICROWAVE FILTERS
2013-05-09
PIER
Vol. 139, 539-558, 2013
download: 120
Cylindrical Microstrip Array Antennas with Slotted Strip-Framed Patches
Alexander Svezhentsev Volodymyr Vitalievich Kryzhanovskiy Guy Vandenbosch
A cylindrical microstrip array antenna with 5 pairs of coupled slotted strip framed patches is analyzed. The patches are proximity-fed by a cylindrical microstrip line. In order to extract the reflection coefficient from the standing wave pattern on the microstrip line, its length is about 5 wavelengths. To the best of the authors' knowledge proximity-fed cylindrical arrays have not been analyzed before using a rigorous MOM model that takes into account all electromagnetic couplings between patches and feeding line. The paper consists of three parts. The first part describes a plane wave excitation of the cylindrical microstrip structure. It introduces some innovating theoretical developments, like the improvement of the asymptote for the spectral Green's function and the explicit surface wave contribution. The second part calculates the radar cross section of the cylindrical microstrip structure with single and coupled slotted strip framed patches. The resonant frequencies, and the amplitude and phase of the current distribution are analysed. The third part describes a design for a proximity-fed array of 5 coupled slotted strip framed patches. It gives the reflection coefficient, current distribution on the patches, and radiation pattern. A very low level of cross polarization (< -40 dB) is achieved. It is shown that the resonant frequencies of the cylindrical array and its planar analogue lie very close to each other. This is due to the common nature of the low frequency slot resonance for the slotted strip framed patch.
CYLINDRICAL MICROSTRIP ARRAY ANTENNAS WITH SLOTTED STRIP-FRAMED PATCHES
2013-05-08
PIER
Vol. 139, 517-538, 2013
download: 127
Elimination of Cruptolestes Ferrungineus s. in Wheat by Radio Frequency Dielectric Heating at Different Moisture Contents
Bijay  Shrestha Daeung Yu Oon-Doo Baik
Radio frequency (RF) dielectric heating was tested to control Cryptolestes ferrungineus S. in the bulk wheat samples (ca.152 g, dia. = 50 mm, ht.= 100 mm) at the MCs (%, w. b.) of 12, 15, and 18 using a pilotscale RF heater (1.5 kW, 27.12MHz) in the batch mode. When the temperature of the hottest spot (geometric center) of the sample, TH was at 80°C, all the adult insects were found dead at the cold spots, near bottom-wall, at 50.7°C to 56.0°C depending up on the wheat MCs. The temperatures of the insect-slurries higher than that of the bulk wheat by 0.8°C to 15.1°C indicated the selective heating of the insects. The mortalities of adult insects were almost constant within the quarantine period, QP1 (5 wk). The elapsed time during QP1 had a significant effect only on the insects' mortalities with the wheat at 12% MC. The wheat MC had only marginal significance on the absolute mortalities of insects. The larvae were completely destroyed at temperatures between 55°C and 60°C. The complete mortality of all life stages (eggs, larvae, pupae, and adults) of the insect was achieved at TH = 80°C without any emergence of the insects during QP2 (8 wk). The RF treatment enhanced the germination of the wheat kernels at 12% MC while it was decreased by 2% to 33% depending up on the wheat MC, and the treatment temperature. Temperature had no significant effect on the falling numbers, and the yields of flour, bran, and shorts, and the peak-bandwidth and the MC of the wheat, and the flour protein values. The means of the mixing-development-time deferred from the controls mostly for the wheat at 15% MC and TH = 70°C, and 18% MC and TH = 70°C and 80°C. The mean-peak-height and the color values varied between 4% and 16%, and 3% and 6% off the controls depending up on the temperatures. The uniform temperature of 60°C should be enough to control all life stages of the insect completely with a little or no changes in the important product quaities and germination of the wheat at MCs safe for the storage. Future research mainly focused on better estimation of the insect-to-grain electric field intensities is essential.
ELIMINATION OF CRUPTOLESTES FERRUNGINEUS S. IN WHEAT BY RADIO FREQUENCY DIELECTRIC HEATING AT DIFFERENT MOISTURE CONTENTS
2013-05-05
PIER
Vol. 139, 499-516, 2013
download: 134
Sliding Scattering Center Model for Extended Streamlined Targets
Kun-Yi Guo Qi-Feng Li Xin-Qing Sheng Marina Gashinova
The knowledge of amplitude and location of sliding scattering centers is necessary for low detectable streamlined targets in many applications, such as precise estimation of shape or velocity of targets, and also target tracking and recognition. Based on the thorough analysis of scattering characteristics, the scattering center features of streamlined targets are presented which demonstrate the dependence of location and amplitude on the target orientation relative to the radar. Then based on these features, an accurate scattering center model for streamlined targets is proposed. The parameters of this model is estimated by genetic algorithm, and then the given model with estimated parameters is validated by full wave numerical method allowing precise backscattered data computation.
SLIDING SCATTERING CENTER MODEL FOR EXTENDED STREAMLINED TARGETS
2013-05-05
PIER
Vol. 139, 479-498, 2013
download: 111
Applications of the Discrete Green's Function in the Finite-Difference Time-Domain Method
Tomasz P. Stefanski
In this paper, applications of the discrete Green's function (DGF) in the three-dimensional (3-D) finite-difference time-domain (FDTD) method are presented. The FDTD method on disjoint domains was developed employing DGF to couple the subdomains as well as to compute the electromagnetic field outside these subdomains. Hence, source and scatterer are simulated in separate subdomains and updating of vacuum cells, being of little interest from a user point of view, can be avoided. In the developed method, the field radiated by a single subdomain is computed as a convolution of DGF with equivalent current sources measured over two displaced Huygens surfaces. Therefore, the computed electromagnetic field is compatible with the FDTD grid and can be applied as an incident wave in a coupled total-field/scattered-field (TFSF) subdomain. In the developed method, the DGF waveforms are truncated using the Hann's window and windowing parameters assuring accuracy of computations are pointed out. The error of the field computations varies between -90 dB and -40 dB depending on the DGF length and excitation waveform. However, if the DGF length is equal to the number of iterations in a simulation, the presented DGF applications return the same results as the direct FDTD method.
APPLICATIONS OF THE DISCRETE GREEN'S FUNCTION IN THE FINITE-DIFFERENCE TIME-DOMAIN METHOD
2013-05-05
PIER
Vol. 139, 445-478, 2013
download: 165
Exposure Optimization in Indoor Wireless Networks by Heuristic Network Planning
David Plets Wout Joseph Kris Vanhecke Luc Martens
Due to the increased use of indoor wireless networks and the concern about human exposure to radio-frequency sources, exposure awareness has increased during recent years. However, current-day network planners rarely take into account electricfield strengths when designing networks. Therefore in this paper, a heuristic indoor network planner for exposure calculation and optimization of wireless networks is developed, jointly optimizing coverage and exposure, for homogeneous or heterogeneous networks. The implemented exposure models are validated by simulations and measurements. As a first novel optimization feature, networks are designed that do not exceed a user-defined electric-field strength value in the building. The influence of the maximally allowed field strength, based on norms in different countries, and the assumed minimal separation between the access point and the human are investigated for a typical office building. As a second feature, a novel heuristic exposure minimization algorithm is presented and applied to a wireless homogeneous WiFi and a heterogeneous WiFi-LTE femtocell network, using a new metric that is simple but accurate. Field strength reductions of a factor 3 to 6 compared to traditional network deployments are achieved and a more homogeneous distribution of the observed field values on the building floor is obtained. Also, the influence of the throughput requirement on the field strength distribution on the building floor is assessed. Moreover, it is shown that exposure minimization is more effective for high than for low throughput requirements and that high field values are more reduced than low field values.
EXPOSURE OPTIMIZATION IN INDOOR WIRELESS NETWORKS BY HEURISTIC NETWORK PLANNING
2013-05-05
PIER
Vol. 139, 423-444, 2013
download: 108
An Investigation on Numerical Characterization of Scattering from Target in a Dielectric Rough Soil Surface
Yu Liang Xiang-Hua Zeng Li-Xin Guo Zhen-Sen Wu
Based on the Propagation-Inside-Layer Expansion (PILE) and the Forward-Backward method (FBM), the composite scattering from the target below a dielectric rough soil surface using the extended PILE (EPILE) combined with the Forward-Backward method (FBM) is studied. The accuracy and efficiency of the EPILE+FBM for this specific type of composite scattering is researched by comparing with the method of moments (MOM), the influences of the target size, target depth, target horizontal distance, the rms height, the correlation length, the incident angle and the soil moisture content, etc, to the bistatic scattering coefficient (BSC) are also investigated.
AN INVESTIGATION ON NUMERICAL CHARACTERIZATION OF SCATTERING FROM TARGET IN A DIELECTRIC ROUGH SOIL SURFACE