Showing papers in "Progress in Electromagnetics Research-pier in 2012"
TL;DR: A novel method that could be applied to the fleld of MR brain image classiflcation and can assist the doctors to diagnose where a patient is normal or abnormal to certain degrees is presented.
Abstract: Automated and accurate classification of MR brain images is extremely important for medical analysis and interpretation. Over the last decade numerous methods have already been proposed. In this paper, we presented a novel method to classify a given MR brain image as normal or abnormal. The proposed method first employed wavelet transform to extract features from images, followed by applying principle component analysis (PCA) to reduce the dimensions of features. The reduced features were submitted to a kernel support vector machine (KSVM). The strategy of Kfold stratified cross validation was used to enhance generalization of KSVM. We chose seven common brain diseases (glioma, meningioma, Alzheimer’s disease, Alzheimer’s disease plus visual agnosia, Pick’s disease, sarcoma, and Huntington’s disease) as abnormal brains, and collected 160 MR brain images (20 normal and 140 abnormal) from Harvard Medical School website. We performed our proposed methods with four different kernels, and found that the GRB kernel achieves the highest classification accuracy as 99.38%. The LIN, HPOL, and IPOL kernel achieves 95%, 96.88%, and 98.12%, respectively. We also compared our method to those from literatures in the last decade, and the results showed our DWT+PCA+KSVM with GRB kernel still achieved the best accurate classification results. The averaged processing time for a 256× 256 size image on a laptop of P4 IBM with 3GHz processor and 2 GB RAM is 0.0448 s. From the experimental data, our method was effective and rapid. It could be applied to the field of MR brain image classification and can assist the doctors to diagnose where a patient is normal or abnormal to certain degrees. Received 14 June 2012, Accepted 23 July 2012, Scheduled 19 August 2012 * Corresponding author: Yudong Zhang (zhangyudongnuaa@gmail.com).
230 citations
TL;DR: The simulation and experimental results at the POSCO steel company verify that the proposed RFID-based steel coil identiflcation system can sense the target RFID tag successfully.
Abstract: This paper describes the radio frequency identiflcation (RFID)-based steel coil identiflcation system for supply chain management in the steel and iron industry. During crane operation, coil information is automatically updated by reading an RFID tag which is attached to the coil. One of the technical challenges associated with the RFID-based coil identiflcation is the fall of the identiflcation performance due to neighboring metallic objects. In order to cope with this problem, a system was developed in two directions. First, an efiective tag attachment method considering the work process and the environmental conditions was proposed. Second, an antenna case was developed to improve the reading performance by minimizing the in∞uence from the attached surface and focusing the RF signal to the target tag. The simulation and experimental results at the POSCO steel company verify that the proposed system can sense the target RFID tag successfully.
137 citations
TL;DR: In this article, a planar ultra-wideband (UWB) antenna with triple band notch characteristics is proposed, which consists of a rectangular radiating patch, a modifled partial ground plane, and has an overall dimension of 30 £ 22mm 2.
Abstract: A compact planar ultra-wideband (UWB) antenna with triple band notch characteristics is proposed in this paper. The antenna consist a rectangular radiating patch, a modifled partial ground plane, and has an overall dimension of 30 £ 22mm 2 . Three resonant elements are placed above the ground plane to generate three notch frequency bands separately in the WiMAX, the lower WLAN and the upper WLAN frequency bands. The proposed antennas are successfully simulated, prototyped and measured. Efiects of the key deign parameters on band notch characteristics are also investigated. The realized antenna achieved an operating bandwidth (VSWR • 2) ranges from 2.9 to more than 11GHz with triple notched bands of 3.26{ 3.71 (12.9%), 5.15{5.37 (8.5%), and 5.78{5.95 (2.9%)GHz. Measured ∞at transfer function and constant group delay within the operating band except notched bands make the proposed antenna suitable for being used in practical UWB applications.
115 citations
TL;DR: In this paper, a UAV Synthetic Aperture Radar (SAR) has been developed at Multimedia University, in collaboration with Agency of Remote Sensing Malaysia (AR).
Abstract: A new Unmanned Aerial Vehicle (UAV) Synthetic Aperture Radar (SAR) has been developed at Multimedia University, in collaboration with Agency of Remote Sensing Malaysia. The SAR operates at C-band, single V V -polarization, with 5m £ 5m spatial resolution. Its unique features include compact in size, light weight, low power and capable of performing real-time imaging. A series of fleld measurements and ∞ight tests has been conducted and good quality SAR images have been obtained. The system will be used for monitoring and management of earth resources such as paddy flelds, oil palm plantation and soil surface. This paper reports the system design and development, as well as some preliminary results of the UAVSAR.
109 citations
TL;DR: This article presents an RF energy harvesting system that can harvest energy from the ambient surroundings at the downlink radio frequency range of GSM-900 band to provide an alternative source of energy for energizing low power devices.
Abstract: Electromagnetic energy harvesting holds a promising future for energizing low power electronic devices in wireless communication circuits. This article presents an RF energy harvesting system that can harvest energy from the ambient surroundings at the downlink radio frequency range of GSM-900 band. The harvesting system is aimed to provide an alternative source of energy for energizing low power devices. The system design consists of three modules: a single wideband 377› E-shaped patch antenna, a pi matching network and a 7-stage voltage doubler circuit. These three modules were fabricated on a single printed circuit board. The antenna and Pi matching network have been optimized through electromagnetic simulation software, Agilent ADS 2009 environment. The uniqueness of the system lies in the partial ground plane and the alignment of induced electric fleld for maximum current ∞ow in the antenna that maximizes the captured RF energy. The design and simulation of the voltage doubler circuit were performed using Multisim software. All the three modules were integrated and fabricated on a double sided FR 4 printed circuit board. The DC voltage obtained from the harvester system in the fleld test at an approximate distance of 50m from GSM cell tower was 2.9V. This voltage was enough to power the STLM20 temperature sensor.
105 citations
TL;DR: Each constitutive parameter directly maps to the dielectric constant of explosive compounds, such as TNT or RDX, making feasible the detection of potential suicide bombers.
Abstract: This paper deals with the problem of detecting potential suicide bombers wearing concealed metallic and dielectric objects. The data produced by Millimeter-Wave-Radar system, working on a Mulptiple Frequency-Multiple Transmitters and Multiple Receivers configuration (MF-MTMR), is synthetically generated by an electromagnetic code based on Finite Differences Frequency Domain (FDFD) method. The numerical code provides the scattered field produced by the subject under test, which is later processed by using a multiple bistatic Synthetic Aperture Radar (SAR) algorithm. The blurring effect produced by the Point Spread Function (PSF) in the SAR image is removed by applying a regularized deconvolution algorithm that uses only magnitude information (no phase). Finally, the SAR algorithm and the deconvolution procedure are tested on a person wearing metallic and dielectric objects. The SAR response of dielectric rods is quite different from the metallic pipes. Our algorithm not only distinguishes between cases but also is capable of estimating the dielectric constant of the rods. Each constitutive parameter directly maps to the dielectric constant of explosive compounds, such as TNT or RDX, making feasible the detection of potential suicide bombers.
96 citations
TL;DR: In this paper, a triangular metamaterials (TMMs) was designed for electromagnetic (EM) absorption reduction at microwave frequencies, which achieved a 1.0923W/kg for SAR 1gm which is 45.44% reduction of the initial SAR value for the case of 1gm SAR.
Abstract: A new triangular metamaterials (TMMs) is designed for electromagnetic (EM) absorption reduction at microwave frequencies in this paper. The reduction of EM absorption with a new TMMs attachment is investigated in this research. The flnite-difierence time-domain method with lossy-Drude model is adopted in this investigation. The method of EM reduction is presented and the efiects of position, distance, and size of metamaterials are analyzed. TMMs have achieved a 1.0923W/kg for SAR 1gm which is 45.44% reduction of the initial SAR value for the case of 1gm SAR.
77 citations
TL;DR: In this paper, a mathematical plasma sheath channel model is proposed and following the roadmap about how to obtain channel characteristic parameter is given, and the performance for QPSK based communication system under the estab- lished plasma channel is evaluated finally.
Abstract: The plasma sheath communication blackout issue for hy- personic or reentry vehicles is addressed from a channel characteristic perspective. Different from previous research, this paper emphasizes the importance of plasma sheath channel in the study of plasma com- munication blackout, and the discussion on transmission and phase shift characteristic of plasma sheath channel and their effect on commu- nication performance was made with detail. A mathematical plasma sheath channel model is proposed and following the roadmap about how to obtain channel characteristic parameter is given. Flow field simulation of a blunt conical body physical was made, and the electron density and collision frequency profile got from flow field result under different incident angle at Mach 10-20 are presented thoroughly. The performance for QPSK based communication system under the estab- lished plasma channel is evaluated finally. It is indicated in our research that channel attenuation feature variation regularity is consistent with that of incident wave or Mach number, but the phase shift variation regularity with incident frequency or Mach number appears fall into chaos because of multiple 360 degree removal of original phase shift from communication view and complicated ratio relationships among incident wave, plasma frequency and collision frequency. Communi- cation simulations result show that bit error rate agree with phase shift chaos well and phase shift exert large influence on present typical racking, telemetry, and command system. Some useful implications obtained from this study to improve communication performance in- clude high frequency, high power and further rapid acquisition/tracing phase-locked loop compensating large phase shift.
76 citations
TL;DR: A novel design of an electromagnetic bandgap (EBG) structure based on the uniplanar compact EBG (UCEBG) concept is proposed in this paper, which is applied to enhance the performance of a single-element microstrip patch antenna and a two-element array conflguration.
Abstract: A novel design of an electromagnetic bandgap (EBG) structure based on the uniplanar compact EBG (UCEBG) concept is proposed in this paper. The structure is realized by inserting split- ring slots inside two reversely connected rectangular patches, which is known as a split-ring slotted electromagnetic bandgap (SRS-EBG) structure. The bandgap properties of the EBG structure are examined by the suspended microstrip line and flnite element methods (FEM). The achieved bandgaps have widths of 4.3 (59.31%) and 5.16GHz (38.88%), which are centered at 7 and 13GHz, respectively. The SRS-EBG is applied to enhance the performance of a single-element microstrip patch antenna (at 7GHz) and a two-element array (at 13GHz) conflguration. A wider bandwidth is obtained with a better re∞ection coe-cient level for the single element antenna; a reduction in mutual coupling of more than 20.57dB is obtained for the array design. In both cases, the gain and radiation characteristics are improved. The results are verifled by measuring the fabricated lab prototype, and a comparison with the computed results showed good agreement.
76 citations
TL;DR: The proposed approach employs a graphics processing unit (GPU) for both numerical integration and matrix assembly and results indicate that the GPU implementation of the matrix generation allows one to achieve speedups by a factor of 81 and 19 over the optimized single- and multi-threaded CPU-only implementations, respectively.
Abstract: This paper presents an e-cient technique for fast gener- ation of sparse systems of linear equations arising in computational electromagnetics in a flnite element method using higher order ele- ments. The proposed approach employs a graphics processing unit (GPU) for both numerical integration and matrix assembly. The per- formance results obtained on a test platform consisting of a Fermi GPU (1x Tesla C2075) and a CPU (2x twelve-core Opterons), indicate that the GPU implementation of the matrix generation allows one to achieve speedups by a factor of 81 and 19 over the optimized single- and multi-threaded CPU-only implementations, respectively.
76 citations
TL;DR: In this article, a broadband horizontally polarized (HP) omnidi-rectional planar antenna is developed for mobile communications, which consists of four printed arc dipoles that form a cir- cular loop for HP omnidirectional radiation.
Abstract: A novel broadband horizontally polarized (HP) omnidi- rectional planar antenna is developed for mobile communications. The proposed antenna consists of four printed arc dipoles that form a cir- cular loop for HP omnidirectional radiation. A broadband feeding net- work which includes four broadband baluns and an impedance match- ing circuit is designed to excite the four arc dipoles. An eight-element linear antenna array is developed for 2G/3G base stations. A broad- band power divider is used to feed the antenna array. Experimental results show that the HP omnidirectional antenna element has a band- width of 31% (1.66{2.27GHz) while its array has a bandwidth of 34% (1.67{2.35GHz) and an omnidirectional antenna gain of » 8dBi. Both of the antenna element and its array have good omnidirectivity over the 10-dB return loss bandwidth. Simulated and measured results for the antenna element and its array are presented.
TL;DR: In this paper, the in∞uence of semi-planar chiral metamaterial (CMM) structures on the important characteristics of circularly polarized (CP) antennas is investigated.
Abstract: The in∞uence of semi-planar chiral metamaterial (CMM) structures on the important characteristics of circularly polarized (CP) antennas is investigated in this paper. Based on this idea, CP planar two-arm Archimedean spiral (ARSPL) antenna and helical antenna are designed and the efiects of chiral covers on their gain (or directivity), axial-ratio (AR), and return loss are considered. The results demonstrate that this method is greatly efiective and the addition of a semi-planar CMM cover at an optimized distance over the CP antenna, signiflcantly improves its gain and axial ratio.
TL;DR: In this paper, a multilayer structure consisting of an alternating sequence of chiral-metamaterial- and dielectric- plates was proposed for the terahertz frequency regime.
Abstract: The lack of wave-plates for the terahertz region opens the way for novel components/devices enabling polarization control at these frequencies. With the aid of chiral metamaterials | a new class of metamaterials | novel possibilities for the fabrication of multilayer structures for the realization of polarization rotators emerge. In this study, we present design and analysis of a polarization rotator for the terahertz frequency regime based on a multilayer structure consisting of an alternating sequence of chiral-metamaterial- and dielectric- plates. The combination of chiral constituents with dielectrics permits optimization of the spectral-fllter and polarization-rotation features. We can generate either polarization-rotation combs or narrow rotation bands with very good and broad sideband suppression, of interest for example for data transmission or sensing purposes.
TL;DR: The two-dimensional images of difierent targets hidden under various fabric sheets are presented and compared to each other to assess the performance of the MMW imaging in detecting the concealed objects of both metallic and dielectric types.
Abstract: Millimeter-wave (MMW) imaging is a powerful tool for the detection of objects concealed under clothing. Several factors including difierent kinds of objects, variety of covering materials and their thickness, accurate imaging of near-fleld scattered data afiect the success of detection. To practice with such considerations, this paper presents the two-dimensional (2D) images of difierent targets hidden under various fabric sheets. The W-band inverse synthetic aperture radar (ISAR) data of various target-covering situations are acquired and imaged by applying both the focusing operator based inversion algorithm and the spherical back-projection algorithm. Results of these algorithms are demonstrated and compared to each other to assess the performance of the MMW imaging in detecting the concealed objects of both metallic and dielectric types.
TL;DR: The design process of a double-sided slotted TORUS axial- ∞ux permanent-magnet (AFPM) motor suitable for direct drive of electric vehicle (EV) is presented and meets all the requirements and limits of EV, and flts the shape and size of a classical-vehicle wheel rim.
Abstract: The design process of a double-sided slotted TORUS axial- ∞ux permanent-magnet (AFPM) motor suitable for direct drive of electric vehicle (EV) is presented. It used sizing equation and Finite Element Analysis (FEA). AFPM motor is a high-torque-density motor easily mounted compactly onto a vehicle wheel, fltting the wheel rim perfectly. A preliminary design is a double-sided slotted AFPM motor with 6 rotor poles for high torque-density and stable rotation. In determining the design requirements, a simple vehicle-dynamics model that evaluates vehicle performance through the typical cruising trip of an automobile was considered. To obtain, with the highest possible torque, the initial design parameters of the motor, AFPM's fundamental theory and sizing equation were applied. Vector Field Opera-3D 14.0 commercial software ran the FEA of the motor design, evaluating and enhancing accuracy of the design parameters. Results of the FEA simulation were compared with those obtained from the sizing equation; at no-load condition, the ∞ux density at every part of the motor agreed. The motor's design meets all the requirements and limits of EV, and flts the shape and size of a classical-vehicle wheel rim. The design process is comprehensive and can be used for an arbitrary EV with an arbitrary cruising scenario.
TL;DR: In this paper, a coupled-fed planar printed antenna mounted on the compact no-ground portion of the system circuit board of a mobile phone with a low proflle of 10mm is proposed and studied.
Abstract: In this article, a coupled-fed planar printed antenna mounted on the compact no-ground portion of the system circuit board of a mobile phone with a low proflle of 10mm is proposed and studied. The presented antenna is formed by a double-branch feeding strip, a shorted coupling strip with two open-ended loops of difierent lengths, and a slotted ground structure consisting of two monopole slots, yet it has a size only 15 £ 50mm 2 . Two wide operating bandwidths of 698{960MHz and 1710{2690MHz can be achieved by these radiating strips, which provide multiple resonant modes at about 750, 1000, 1750, 2300 and 2900MHz. In addition, with the presence of the two narrow slots and a chip inductor (L = 1:5nH), in this study, the printed antenna can lead to much widened bandwidths in both the antenna's lower and upper bands to cover LTE700/GSM850/900 and DCS1800/PCS1900/UMTS2100/LTE2300/2500, respectively. Good radiation e-ciency and antenna gain for frequencies over the desired operating bands are obtained. Detailed design considerations of the proposed antenna are described, and both experimental and simulated results are also presented and discussed.
TL;DR: A model for this power consumption of wireless access networks is presented and three base station types are investigated: macrocell, microcell, and femtocell base stations.
Abstract: 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.
TL;DR: The design of a fully printed extremely wideband antenna and creating triple band-notched functions are addressed andMeasurements demonstrate that the proposed printed base antenna has an extremely wide 2:1 VSWR bandwidth from 0.72GHz to 25GHz with a ratio bandwidth of 34:1.
Abstract: Three notched bands are generated, at selected frequen- cies, in an extremely wideband base antenna to support multiple com- munication systems while avoiding inference from other existing nar- rowband systems. The design of a fully printed extremely wideband antenna and creating triple band-notched functions are addressed in this paper. Measurements demonstrate that the proposed printed base antenna has an extremely wide 2:1 VSWR bandwidth from 0.72GHz, to 25GHz with a ratio bandwidth of 34:1. The antenna has a simple structure and can be fabricated at low cost for multi-band and wide- band wireless communication devices. Besides, this paper presents a technique to form three notched bands within the operating frequency range of the base antenna. By introducing a half-wavelength U-shaped defected ground structure (DGS) and a pair of quarter-wavelength open arc-shaped slots to the radiating patch, three notched bands are created to prevent interference from WLAN (2.4{2.484GHz and 5.15{ 5.85GHz) systems and downlinks of X-band satellite communication (7.25{7.75GHz) systems.
TL;DR: In this article, a tri-band bandpass fllter for the application of GSM (1.8GHz), WiMAX (2.7GHz) and UWB (3.3{ 4.8 GHz) is proposed.
Abstract: In this paper, a design of new tri-band bandpass fllter for the application of GSM (1.8GHz), WiMAX (2.7GHz) and UWB (3.3{ 4.8GHz) is proposed. The flrst two narrow passbands are created, and the bandwidth of the third passband can be tuned by properly selecting the impedance ratio (R) and physical length ratio (u) of the asymmetric stepped-impedance resonator. To improve passband performance and form the UWB passband, a U-shape defected ground structure and extra extended coupling lines are integrated with the asymmetric SIR. Due to the three transmission zeros appearing near the passband edges, the band selectivity of the proposed fllter is much improved. The fllter was fabricated, and the measured results have a good agreement with the full-wave simulated ones.
TL;DR: In this paper, the efiect of impedance mismatch of a HF- band wireless power transfer system is carefully investigated and two compensation methods are suggested to overcome this within a short range, where frequent impedance mismatch can occur.
Abstract: High-frequency (HF) band wireless power transfer systems ofier the promise of cutting the last cord, allowing users to seamlessly recharge mobile devices as easily as wireless communication. Yet there are still many technical issues that need to be overcome. Among them, one of the most di-cult problems is maintaining impedance match over a short range, where the distance between a transmitter and receiver could vary. In this paper, the efiect of impedance mismatch of a HF- band wireless power transfer system is carefully investigated and two compensation methods are suggested to overcome this within a short range, where frequent impedance mismatch can occur. Each method has pros and cons. In order to verify the feasibility of the proposed methods, HF-band wireless power transfer systems, with a pair of rectangular loop resonators, were designed. The e-ciency and input impedance variation were simulated and measured. From these results, proposed methods show enhanced e-ciency performance than a typical wireless power transfer system without any compensation circuits.
TL;DR: In this paper, a composite structure is proposed which is able to dissipate such energy by placing a thin absorbing layer below the FSS ground, and the optimal value of the foam spacer thickness between the ground and the absorbing layer is investigated by an ecient equivalent transmission line approach.
Abstract: An e-cient strategy for reducing the signature of an antenna is to substitute the conventional solid ground plane with a patterned ground plane thus letting the incoming energy to pass through the structure except over the operating band of the antenna. However, in a real environment, the energy ∞owing through the FSS (Frequency Selective Surface) can be intercepted by eventual scatterers located behind the antenna, so to nullify the RCS (Radar Cross Section) reduction. To overcome this drawback, a novel composite structure is proposed which is able to dissipate such energy by placing a thin absorbing layer below the FSS ground. It is shown that a careful analysis has to be performed to accomplish this goal since the transparent antenna array and the backing absorber strongly interact and thus they cannot be separately designed. The optimal value of the foam spacer thickness between the FSS ground and the absorbing layer is investigated by an e-cient equivalent transmission line approach. Criteria for enlarging the low-RCS band with respect to the free space design are also provided. An antenna array prototype backed by the thin multilayer structure is flnally manufactured and tested.
TL;DR: In this article, the detuning and impedance mismatch of antennas implanted inside the human body was quantified using electromagnetic modeling based on the flnite-difierence time-domain method and high-resolution anatomical models.
Abstract: This study quantifles the detuning and impedance mismatch of antennas implanted inside the human body. Maximum frequency shifts caused by variations in the electrical properties of body tissues and difierent anatomical distributions were derived. The results are relevant to the design of implantable antennas. They indicate the bandwidth enhancement and initial tuning necessary for correct functioning. The study was carried out using electromagnetic modeling based on the flnite-difierence time-domain method and high- resolution anatomical models. Four anatomical computer models of two adults and two children were used. The implanted antennas operated in the Medical Implant Communication Service band. The most important detuning and impedance mismatch was found for subcutaneous locations and in areas where a layer of fat tissue was present. The maximum frequency shift towards higher frequencies was 70MHz. The frequency shift did not occur symmetrically around 403MHz, but was shifted towards higher frequencies.
TL;DR: In this article, the authors used the numerical steepest descent path (numerical SDP) method in complex analysis theory to calculate the highly oscillatory physical optics integral with quadratic phase and amplitude variations on the triangular patch.
Abstract: In this work, we use the numerical steepest descent path (numerical SDP) method in complex analysis theory to calculate the highly oscillatory physical optics (PO) integral with quadratic phase and amplitude variations on the triangular patch. The Stokes' phenomenon will occur due to various asymptotic behaviors on difierent domains. The stationary phase point contributions are carefully studied by the numerical SDP method and complex analysis using contour deformation. Its result agrees very well with the leading terms of the traditional asymptotic expansion. Furthermore, the resonance points and vertex points contributions from the PO integral are also extracted. Compared with traditional approximate asymptotic expansion approach, our method has signiflcantly improved the PO integral accuracy by one to two digits (10 i1 to 10 i2 ) for evaluating the PO integral. Moreover, the computation efiort for the highly oscillatory integral is frequency independent. Numerical results for PO integral on the triangular patch are given to verify the proposed numerical SDP theory.
TL;DR: The results show that the ADIWO provides su-cient steering ability regarding the main lobe and the nulls, works faster than the PSO and achieves better SLL than thePSO and MVDR.
Abstract: An improved adaptive beamforming technique of antenna arrays is introduced. The technique is implemented by using a novel Invasive Weed Optimization (IWO) variant called Adaptive Dispersion Invasive Weed Optimization (ADIWO) where the seeds produced by a weed are dispersed in the search space with standard deviation specifled by the fltness value of the weed. The adaptive seed dispersion makes the ADIWO converge faster than the conventional IWO. This behavior is verifled by applying both the ADIWO and the conventional IWO on well-known test functions. The ADIWO method is utilized here as an adaptive beamformer that makes a uniform linear antenna array steer the main lobe towards the direction of arrival (DoA) of a desired signal, form nulls towards the respective DoA of several interference signals and achieve low side lobe level (SLL). The proposed ADIWO based beamformer is compared to a Particle Swarm Optimization (PSO) based beamformer and a well known beamforming method called Minimum Variance Distortionless Response (MVDR). Several cases have been studied with difierent number of interference signals and difierent power level of additive zero-mean Gaussian noise. The results show that the ADIWO provides su-cient steering ability regarding the main lobe and the nulls, works faster than the PSO and achieves better SLL than the PSO and MVDR.
TL;DR: In this paper, the chaotic binary particle swarm optimization (CBPSO) algorithm is presented as a useful alternative for the synthesis of thinned arrays, which can be improved by nonlinear inertia weight with chaotic mutation to increase the diversity of particles.
Abstract: Traditional optimization methods are not well suitable for thinning large arrays to obtain a low sidelobe level (SLL). The chaotic binary particle swarm optimization (CBPSO) algorithm is presented as a useful alternative for the synthesis of thinned arrays. The proposed algorithm can be improved by nonlinear inertia weight with chaotic mutation to increase the diversity of particles. Two examples have been presented and solved. Simulation results are proposed to compare with published results to verify the efiectiveness of the proposed method for both linear and planar arrays.
TL;DR: In this paper, a dual-band, dual-polarized 1£4 antenna array design for telecommunication base station is presented, which is based upon an aperture stacked patch layout and incorporates a simple and novel dual-layered feeding technique.
Abstract: This paper presents a new dual-band, dual-polarized 1£4 antenna array design for telecommunication base station. One of the bands covers global system for mobile communication (GSM) band, while the other covers both digital communication system (DCS) and universal mobile telecommunication system (UMTS) bands. The antenna is based upon an aperture stacked patch layout and incorporates a simple and novel dual-layered feeding technique to achieve dual polarized radiation. For feeding the array elements, a corporate feed network is used. In order to achieve appropriate matching in both bands, a three-section Chebyshev transformer has been designed. The proposed antenna shows good port decoupling, less than i30dB for dual linear polarization over its operating bands. Peak antenna gains about 11dBi and 11.6dBi have been obtained for lower and upper bands, respectively. The efiort was directed toward the design of a single standalone dual-polarized antenna to cover all three bands.
TL;DR: Fully integrated printed RFID antennas show potential solution for item level labeling applications and need to accommodate the antenna during the package printing process.
Abstract: Fully integrated printed RFID antennas show potential solution for item level labeling applications. In order to accommodate the antenna during the package printing process, it is vastly preferred ...
TL;DR: In this article, the dispersion curves and energy ∞ux of guided modes for three kinds of uniaxial chiral media are presented, and the characteristic equation of the guided modes is derived.
Abstract: The characteristics of guided modes in the circular waveguide consist of uniaxial chiral medium have been investigated. The characteristic equation of guided modes is derived. The dispersion curves and energy ∞ux of guided modes for three kinds of uniaxial chiral media are presented. Unusual dispersion characteristics and negative energy ∞ux are found, i.e., backward wave is supported in the uniaxial chiral waveguide.