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Showing papers in "Progress in Electromagnetics Research B in 2010"


Journal ArticleDOI
TL;DR: In this paper, four rectangular patch antennas for on-body wireless communications in the 2.45GHz WLAN band were designed and developed using different varieties of cotton and polyester clothing.
Abstract: Utilization of wearable textile materials for the develop- ment of microstrip antenna segment has been rapid due to the recent miniaturization of wireless devices. A wearable antenna is meant to be a part of the clothing used for communication purposes, which includes tracking and navigation, mobile computing and public safety. This pa- per describes design and development of four rectangular patch anten- nas employing difierent varieties of cotton and polyester clothing for on-body wireless communications in the 2.45GHz WLAN band. The impedance and radiation characteristics are determined experimentally when the antennas are kept in ∞at position. The performance deterio- ration of a wearable antenna is analyzed under bent conditions too to check compatibility with wearable applications. Results demonstrate the suitability of these patch antennas for on-body wireless communi- cations.

156 citations


Journal ArticleDOI
TL;DR: The authors propose pattern synthesis methods to reduce the sidelobe levels with flxed FNBW by making the scanned array thinned based on two difierent global optimization algorithms, namely Gravitational Search Algorithm (GSA) and modifled Particle Swarm Optimization (PSO) algorithm.
Abstract: Scanning a planar array in the x-z plane directs the beam peak to any direction ofi the broadside along the same plane. Reduction of sidelobe level in concentric ring array of isotropic antennas scanned in the x-z plane result in a wide flrst null beamwidth (FNBW). In this paper, the authors propose pattern synthesis methods to reduce the sidelobe levels with flxed FNBW by making the scanned array thinned based on two difierent global optimization algorithms, namely Gravitational Search Algorithm (GSA) and modifled Particle Swarm Optimization (PSO) algorithm. The thinning percentage of the array is kept more than 45 percent and the flrst null beamwidth (FNBW) is kept equal to or less than that of a fully populated, uniformly excited and 0:5‚ spaced concentric circular ring array of same scanning angle and same number of elements and rings.

101 citations


Journal ArticleDOI
Bo Zhu, Ci Huang, Yijun Feng1, Junming Zhao, and Tian Jiang 
TL;DR: In this paper, a dual-band switchable metamaterial electromagnetic absorber with nearly perfect peak absorption was proposed, based on the dipole mode of the electric resonator in the unit cell.
Abstract: This paper presents the design, fabrication and measure- ment of a dual band switchable metamaterial electromagnetic absorber. The unit cell of the metamaterial consists of dipole mode electric res- onators coupled by microwave diodes on one side of a dielectric sub- strate and metallic ground plane on the other side. Simulation and measurement results show that by forward or reverse biasing the diodes so as to change the coupling between the resonators, the absorber can be dynamically switched to operate in two adjacent frequency bands with nearly perfect peak absorption. Field distribution reveals the physical origin of the switchable performance based on the dipole mode of the electric resonator in the unit cell. It is also demonstrated that the frequency difierence between the two bands can be tuned by adjusting the loading positions of the diodes with unchanged high absorption, which helps to design absorbers with speciflc switchable working fre- quencies in practical applications.

75 citations


Journal ArticleDOI
TL;DR: In this article, the distribution of drop size is assumed to be lognormal to model the rain attenuation in the frequency range of 10{100GHz, assuming single scattering of spherical rain drops, and a comparison shows that signiflcant difierences between ITU-R model and DSD derived values occur at high frequency and at high rain rates for different regions.
Abstract: Rain drop size distributions (DSD) are measured with disdrometers at flve difierent climatic locations in the Indian tropical region. The distribution of drop size is assumed to be lognormal to model the rain attenuation in the frequency range of 10{100GHz. The rain attenuation is estimated assuming single scattering of spherical rain drops. Difierent attenuation characteristics are observed for difierent regions due to the dependency of DSD on climatic conditions. A comparison shows that signiflcant difierences between ITU-R model and DSD derived values occur at high frequency and at high rain rates for difierent regions. At frequencies below 30GHz, the ITU-R model matches well with the DSD generated values up to 30mm/h rain rate but difier above that. The results will be helpful in understanding the pattern of rain attenuation variation and designing the systems at EHF bands in the tropical region.

71 citations


Journal ArticleDOI
TL;DR: In this paper, three types of new metamaterials, concentric and non-concentric conflgurations, are designed, and their electromagnetic response is investigated, and constitutive and S parameters are computed using retrieval algorithm.
Abstract: In this paper, we study tunable metamaterial structures whose unit cell has triangular split ring resonator and wire strip for S- and C-microwave bands. Three types of new metamaterials, concentric and non-concentric conflgurations, are designed, and their electromagnetic response is investigated. Constitutive and S parameters are computed using retrieval algorithm to demonstrate the properties of the proposed new metamaterial designs. In addition, the electric fleld distribution on the metallic parts of the structure is illustrated for one design of the each sample. It is shown that the studied new metamaterials exhibit double negative properties in the frequency region of interest. The main advantage of this study based on the proposed structures is having the tunability in terms of the substrate thickness and the possibility of pronounced loss reduction.

68 citations



Journal ArticleDOI
TL;DR: This work proposes a technique to detect and characterize activity associated with a stationary human in through-the-wall scenarios using a Doppler radar system, using bio-mechanical human arm movement models and the empirical mode decomposition (EMD) algorithm for doppler feature extraction.
Abstract: In homeland security and law enforcement situations, it is often required to remotely detect human targets obscured by walls and barriers. In particular, we are speciflcally interested in scenarios that involve a human whose torso is stationary. We propose a technique to detect and characterize activity associated with a stationary human in through-the-wall scenarios using a Doppler radar system. The presence of stationary humans is identifled by detecting Doppler signatures resulting from breathing, and movement of the human arm and wrist. The irregular, transient, non-uniform, and non-stationary nature of human activity presents a number of challenges in extracting and classifying Doppler signatures from the signal. These are addressed using bio-mechanical human arm movement models and the empirical mode decomposition (EMD) algorithm for Doppler feature extraction. Experimental results demonstrate the efiectiveness of our approach to extract Doppler signatures corresponding to human activity through walls using a 750-MHz Doppler radar system.

57 citations


Journal ArticleDOI
TL;DR: In this paper, a metamaterial re∞ective surface (MRS) was proposed as a superstrate for a single-feed circularly polarized microstrip patch antenna (SFCP-MPA).
Abstract: This paper proposes a metamaterial re∞ective surface (MRS) as a superstrate for a single-feed circularly polarized microstrip patch antenna (SFCP-MPA). It illustrates a simultaneous enhancement on antenna gain, impedance bandwidth (ZBW) and axial-ratio bandwidth (ARBW) by adding the MRS atop the SFCP- MPA. The MRS can enhance the ZBW and ARBW by 3.5 and 9.9 times, respectively, compared to the circularly polarized patch source. Moreover, the gain of the CP-MPA with the MRS is 7dB higher than that of the conventional CP-MPA. The small spacing between the MRS and patch source is another merit in the present design, which is as low as ‚-/16, as it results in a low-proflle antenna design that well suits modern wireless communications.

55 citations


Journal ArticleDOI
TL;DR: A novel classiflcation method is examined, using Principal Component Analysis (PCA) to extract the most important tumour features from the RTS to be applied to the principal components as a method of classifying these tumours.
Abstract: Microwave Imaging (MI) has been widely investigated as a method to detect early stage breast cancer based on the dielectric contrast between normal and cancerous breast tissue at microwave frequencies. Furthermore, classiflcation methods have been developed to difierentiate between malignant and benign tumours. To successfully classify tumours using Ultra Wideband (UWB) radar, other features have to be examined other than simply the dielectric contrast between benign and malignant tumours, as contrast alone has been shown to be insuflcient. In this context, previous studies have investigated the use of the Radar Target Signature (RTS) of tumours to give valuable information about the size, shape and surface texture. In this study, a novel classiflcation method is examined, using Principal Component Analysis (PCA) to extract the most important tumour features from the RTS. Support Vector Machines (SVM) are then applied to the principal components as a method of classifying these tumours. Finally, several difierent classiflcation architectures are compared. In this study, the performance of classiflers is tested using a database of 352 tumour models, comprising four difierent sizes and shapes, using the cross validation method.

55 citations


Journal ArticleDOI
TL;DR: In this article, the Rayleigh roughness criterion is extended to the case of rough layers, which provides an interesting qualitative tool for estimating the degree of electromagnetic roughness of rough layer.
Abstract: In the domain of electromagnetic wave propagation in the presence of rough surfaces, the Rayleigh roughness criterion is a widely- used means to estimate the degree of roughness of considered surface. In this paper, this Rayleigh roughness criterion is extended to the case of rough layers. Thus, it provides an interesting qualitative tool for estimating the degree of electromagnetic roughness of rough layers.

53 citations


Journal ArticleDOI
TL;DR: In this paper, the authors numerically compare the mode birefringence and conflnement loss with four patterns (case A{D) of index-guiding photonic crystal flbers (PCF) using the flnite element method.
Abstract: We numerically compare the mode birefringence and conflnement loss with four patterns (case A{D) of index-guiding photonic crystal flbers (PCF) using the flnite element method. These PCFs are composed of a solid silica core surrounded by difierent sizes of elliptical air holes and a cladding which consist of the same elliptical air holes in flber cladding with tetragonal lattice. The maximal modal birefringence and lowest conflnement loss of our proposed case A structure at the excitation wavelength of ‚ = 1550nm can be achieved at a magnitude of 5:3 £ 10 i2 (which is the highest value to our knowledge) and less than 0.051dB/km (an acceptable value less than 0.1dB/km) with only four rings of air holes in flber cladding, respectively. The merit of our designed PCFs is that the birefringence and conflnement loss can be easily controlled by turning the pitch (hole to hole spacing) of elliptical air holes in PCF cladding.

Journal ArticleDOI
TL;DR: An improved Central Force Optimization algorithm for antenna optimization is presented and exhibits excellent performance against recognized antenna benchmark problem specifically designed to evaluate optimization evolutionary algorithms for antenna applications.
Abstract: An improved Central Force Optimization (CFO) algorithm for antenna optimization is presented. CFO locates the global extrema an objective function to be maximized, in this case antenna directivity, by flying “probes” through the decision space (DS). The new implementation includes variable initial probe distribution and decision space adaptation. CFO’s performance is assessed against a recognized antenna benchmark problem specifically designed to evaluate optimization evolutionary algorithms for antenna applications. In addition, summary results also are presented for a standard twentythree function suite of analytic benchmarks. The improved CFO implementation exhibits excellent performance.

Journal ArticleDOI
TL;DR: Experimental results of this single feed antenna indicate that it meets all current requirements for in-cabin wireless communication needs.
Abstract: In this paper, a multifunctional microstrip antenna is designed, fabricated and experimentally verifled for operation in AWS, GSM, WiMAX and WLAN bands This microstrip patch antenna has two U-shaped slots to achieve the dual wideband operation required to meet these speciflcations The dimensions and locations of the U- slots are designed appropriately The thick substrate used here helps in integrating the antenna with the existing aircraft panel material while achieving wide bandwidths Experimental results of this single feed antenna indicate that it meets all current requirements for in-cabin wireless communication needs

Journal ArticleDOI
TL;DR: In this paper, the design and analysis of a Microstrip Re∞ectarray Antenna (MRA) with Minkowski shape radiating element at frequency of 11GHz is described.
Abstract: This paper describes the design and analysis of a Microstrip Re∞ectarray Antenna (MRA) with Minkowski shape radiating element at frequency of 11GHz. This structure has been analyzed and compared with the traditional re∞ectarray element (square element patch). It is found that this antenna array has lower sidelobe level (SLL) characteristic which is down to i25dB. This MRA has maximum realized gain of 29.6dB with half-power beamwidth (HPBW) of 3.7 - . The validation for the proposed MRA is done by comparing the simulated and measured E-plane radiation pattern. A very good agreement is found from the comparison between simulation and measurement.

Journal Article
TL;DR: In this paper, an overview of important concepts and formulas involved in the application of coupling coe-cients of microwave resonators for the design of bandpass fllters with a particular emphasis on the frequency dispersion.
Abstract: This paper is an overview of important concepts and formulas involved in the application of coupling coe-cients of microwave resonators for the design of bandpass fllters with a particular emphasis on the frequency dispersion of coupling coe-cients. The presumptions and formulas are classifled into accurate, approximate, and erroneous ones.

Journal ArticleDOI
TL;DR: It is shown that the CFO results are comparable to those found by the self-adaptive difierential evolution (SADE) algorithm and better than Those found by particle swarm optimization (PSO) and gravitational search algorithm (GSA).
Abstract: Central Force Optimization (CFO) is a new multi- dimensional search metaheuristic based on the metaphor of gravita- tional kinematics. In this paper, for the flrst time, a modifled CFO algorithm is applied to the optimal design of multilayer microwave absorbers (for normal incidence) in a speciflc frequency range. Sev- eral numerical examples are presented, in which the CFO results are compared with those found by other evolutionary algorithms. It is shown that the CFO results are comparable to those found by the self-adaptive difierential evolution (SADE) algorithm and better than those found by particle swarm optimization (PSO) and gravitational search algorithm (GSA).

Journal ArticleDOI
TL;DR: In this paper, a mathematical model for converting terrestrial rain attenuation data to be used for satellite applications at Ku-band was presented, and the proposed technique, the ITU-R P 618-9, together with a combination of ITU R P 530-12 and the revised Moupfouma model have been adopted for satellite and terrestrial RA predictions, respectively.
Abstract: Rain attenuation is one of the most crucial factors to be considered in the link budget estimation for microwave satellite communication systems, operating at frequencies above 10GHz. This paper presents a mathematical model for converting terrestrial rain attenuation data to be used for satellite applications at Ku-band. In the proposed technique, the ITU-R P 618-9, together with a combination of ITU-R P 530-12 and the revised Moupfouma model have been adopted for satellite and terrestrial rain attenuation predictions, respectively. The model has been used for transforming the measured rain attenuation data of some DIGI MINI-LINKS operating at 15GHz in Malaysia, to be used for MEASAT 2 applications. It was found that the model predictions are fairly reasonable when compared with direct beacon measurements in Malaysia and similar tropical locations. The model will provide a relatively accurate method for transforming the measured terrestrial rain attenuation to be used for satellite applications; and therefore substantially reduce the cost of implementing Earth-satellite links in some tropical regions that have su-cient rain attenuation data for the terrestrial links.

Journal ArticleDOI
TL;DR: In this paper, dual-band, single and double negative metamatteri- als composed of nonconcentric and difierent sized delta loop resonators are presented, which provide two distinct resonant frequencies in the microwave region.
Abstract: Novel, dual-band, single and double negative metamateri- als composed of nonconcentric and difierent sized delta loop resonators are presented. The proposed structures provide two distinct resonant frequencies in the microwave region. Efiective medium parameters of these metamaterial structures are extracted using retrieval method to demonstrate the presence of the mentioned frequencies. In addition, equivalent circuit model for the individual magnetic resonator and wire strip is presented to give a clear explanation for the resonance behav- ior of the structures and to validate the proposed designs. The results show that the proposed metamaterials can be used as an alternative to the known counterparts especially when a dual-band operation is needed at the frequency region of interest.

Journal ArticleDOI
TL;DR: A capacitive method for measuring hand grip position on a mobile phone equipped with a dual-band planar inverted-F antenna and a monopole antenna and an antenna-integrated capacitive sensor proved to have sensitivity of 420fF and 115fF, making them both reasonable solutions for hand grip sensors in mobile applications.
Abstract: A capacitive method for measuring hand grip position on a mobile phone equipped with a dual-band planar inverted-F antenna (PIFA) and a monopole antenna was studied using difierent electrode arrangements. A capacitive sensor with a dual-electrode conflguration and an antenna-integrated capacitive sensor for hand grip recognition were developed. The sensitivities of the sensors were measured along the front, side and back of the phone. The dual-electrode sensor conflguration exhibited its best sensitivity of 29fF at the bottom end of the phone. The PIFA antenna-integrated sensor proved to have sensitivity of 420fF and the monopole antenna-integrated sensor had sensitivity of 115fF, making them both reasonable solutions for hand grip sensors in mobile applications.

Journal ArticleDOI
TL;DR: In this paper, a planar monopole antenna for UWB communications with a notched behavior in the two sub-bands UNII1 and UNII2 of the WLAN band is presented.
Abstract: In this paper, a planar monopole antenna for Ultra- Wideband (UWB) communications with a notched behavior in the two sub-bands UNII1 and UNII2 of the Wireless Local Area Network (WLAN) band is presented. The antenna geometry is described by means of a spline curve and a rectangular slot. Numerical and experimental results are reported to assess the efiectiveness of the proposed design in terms of impedance matching and radiation characteristics.

Journal ArticleDOI
TL;DR: This article compared time-modulated antenna structures with other methods for linear array synthesis such as the excitation method and the phase-position synthesis method on the basis of the approximated Pareto Fronts yielded by MOEA/D-DE and the best compromise solutions determined from the Pare to optimal set with a fuzzy membership- function based method.
Abstract: This article proposes a Multi-objective Optimization (MO) framework for the design of time-modulated linear antenna arrays with ultra low maximum Side Lobe Level (SLL), maximum Side Band Level (SBL) and main lobe Beam Width between the First Nulls (BWFN). In contrast to the existing optimization-based methods that attempt to minimize a weighted sum of SLL, SBL, and BWFN, we treat these as three distinct objectives that are to be achieved simultaneously and use one of the best known Multi- Objective Evolutionary Algorithms (MOEAs) of current interest called MOEA/D-DE (Decomposition based MOEA with Difierential Evolution operator) to determine the best compromise among these three objectives. Unlike the single-objective approaches, the MO approach provides greater ∞exibility in the design by yielding a set of equivalent flnal solutions from which the user can choose one that attains a suitable trade-ofi margin as per requirements. We compared time-modulated antenna structures with other methods for linear array synthesis such as the excitation method and the phase-position synthesis method on the basis of the approximated Pareto Fronts (PFs) yielded by MOEA/D-DE and the best compromise solutions determined from the Pareto optimal set with a fuzzy membership- function based method. The flnal results obtained with MOEA/D-DE were compared with the results achieved by two state-of-the-art single objective optimization algorithms and flve other MO algorithms. Our simulation studies on three instantiations of the design problem re∞ect the superiority of the MOEA/D-DE based design of time-modulated linear arrays.

Journal ArticleDOI
TL;DR: This paper will design a multi-∞oor indoor positioning system based on Bayesian Graphical Models (BGM), which will use multiple sets each set contains a collection of sampling techniques, the accuracy of each set will be compared with each other.
Abstract: In recent years, location determination systems have gained a high importance due to their rule in the context aware systems. In this paper, we will design a multi-∞oor indoor positioning system based on Bayesian Graphical Models (BGM). Graphical models have a great ∞exibility on visualizing the relationships between random variables. Rather than using one sampling technique, we are going to use multiple sets each set contains a collection of sampling techniques, the accuracy of each set will be compared with each other.

Journal ArticleDOI
TL;DR: In this paper, the plane wave shield- ing efiectiveness of new combination of these materials is evaluated as a function of angle of incidence for Single, Double and Laminated.
Abstract: Shielding prevents coupling of undesired radiated electro- magnetic energy into equipment otherwise susceptible to it. In view of this, some studies on shielding efiectiveness of difierent shields against angle of incidence with conductors and conductive polymers using plane-wave theory are carried out in this paper. The plane wave shield- ing efiectiveness of new combination of these materials is evaluated as a function of angle of incidence for Single, Double and Laminated

Journal ArticleDOI
TL;DR: In this paper, an analysis of a full-wave integral representation, with the equivalent currents as unknowns, is used to diagnose the radome's interaction with the radiated fleld.
Abstract: In this paper an inverse source problem is investigated. The measurement set-up is a re∞ector antenna covered by a radome. Equivalent currents are reconstructed on a surface shaped as the radome in order to diagnose the radome's interaction with the radiated fleld. To tackle this inverse source problem an analysis of a full-wave integral representation, with the equivalent currents as unknowns, is used. The extinction theorem and its associated integral equation ensure that the reconstructed currents represent sources within the radome. The axially symmetric experimental set-up reduces the computational complexity of the problem. The resulting linear system is inverted by using a singular value decomposition. We visualize how the presence of the radome alters the components of the equivalent currents. The method enables us to determine the phase shift of the fleld due to the transmission of the radome, i.e., the IPD (insertion phase delay). Also, disturbances due to defects, not observable in the measured near fleld, are localized in the equivalent currents.

Journal ArticleDOI
TL;DR: In this article, a re∞ectarray confluration is proposed for low-loss applications at millimeter-wave (MW) frequency bands, based on the use of dielectric resonator antennas (DRA) as radiating unitcells.
Abstract: A new re∞ectarray conflguration is proposed for low-loss applications at millimeter waves. It is based on the use of dielectric resonator antennas (DRA) as radiating unit-cells. The phase response of the elementary cell is controlled by adjusting the length of a parasitic narrow metal strip printed on the top of each DRA. A 330 - phase dynamic range is obtained for DRAs made in rigid thermosetting plastic ("r = 10). As the antenna radiating aperture is non ∞at, an original low-cost fabrication process is also introduced in order to fabricate the parasitic strips on the DRA surface. A 24 £ 24- element array radiating at broadside has been designed at 30GHz and characterized between 29 and 31GHz. The antenna gain reaches 28.3dBi at 31GHz, and the measured i1dB-gain radiation bandwidth is 5.2%. The 3.2dB loss observed between the measured gain and theoretical directivity is mainly due to the spillover loss (2.3dB). The total dielectric and conductor loss is less than 0.9dB.

Journal ArticleDOI
TL;DR: In this paper, a new antenna structure is formed by combining the concept of reconfigurable planar antenna array (RPAA) with the parasitic elements to produce beam steering patterns.
Abstract: A new antenna structure is formed by combining the concept of reconfigurable planar antenna array (RPAA) with the parasitic elements to produce beam steering patterns. The antenna has been integrated with the PIN diode switches that enable the beam to be steered in the desired direction. This has been done by changing the switch state to either on or off mode. In this work, a number of parasitic elements have been applied to the antenna, namely reflectors and directors. They are placed in between the driven elements, which is aimed to improve the beam steering angle. With such configuration, the main beam radiated by the array can be tilted due to the effect of mutual coupling between the driven elements and parasitic elements (reflectors and director). The unique property of this antenna design is that instead of fabricating all together in the same plane, the antenna's feeding network is separated from the antenna radiating elements (the patches) by an air gap distance. This allows reducing the spurious effects from the feeding line. The optimization results for the resonant frequencies of the antennas with variable air gap heights are also been studied. The antenna is made for 5.8 GHz. Good agreement is achieved between the simulation and measurement.

Journal ArticleDOI
TL;DR: In this paper, a two-layer non-destructive method for characterizing the electric and magnetic properties of lossy conductor-backed magnetic materials using a ∞anged rectangular-waveguide probe is examined.
Abstract: A two-layer nondestructive method for characterizing the electric and magnetic properties of lossy conductor-backed magnetic materials using a ∞anged rectangular-waveguide probe is examined. The two re∞ection measurements necessary to determine both permittivity and permeability are made by flrst applying the probe to the material under test and then applying the probe to a known-material layer placed on top of the material under test. The theoretical re∞ection coe-cient is obtained using a rigorous full-wave solution, and an extrapolation scheme is used to minimize the error due to truncating the modal expansion of the waveguide flelds. An error analysis is performed to compare the performance of the technique to the two-thickness method, which utilizes two difierent thicknesses of the material under test. The properties of the known material layer that result in the least error due to network analyzer uncertainty are determined. The sensitivity of the two-layer method is also explored and discussed.

Journal ArticleDOI
TL;DR: Tang et al. as mentioned in this paper presented a novel design technique of the quad-band small internal antenna covering GSM-900/DCS-1800/PCS-1900/IMT-2000 bands within the limit of a 44×25×4mm3 volume.
Abstract: The development of compact antennas plays an important role in the rapidly growing mobile communication market. This paper presents a novel design technique of the quad-band small internal antenna covering GSM-900/DCS-1800/PCS-1900/IMT-2000 bands. The innovative quad-band built-in handset antenna is developed within the limit of a 44×25×4mm3 volume. The following document describes a new idea of increasing operational bandwidth for the compact planar inverted F antenna (PIFA). The proposed compact antenna introduces the open-end slots in the ground plane almost all under the radiating patch. The size reduction method is attractive for practical antenna implementations. In addition, the end user’s hand handling effects on the performances of the proposed antenna are studied. Received 6 July 2010, Accepted 7 August 2010, Scheduled 13 August 2010 Corresponding author: I-T. Tang (tangitseng@gmail.com). 174 Lin, Tang, and Hong

Journal ArticleDOI
TL;DR: A synthesis strategy is proposed for the case of planar arrays and ring shaped patterns which does not require the exploitation of global optimization procedures and may serve both as a reference solution for more general synthesis procedures, and as an elementary brick for more cumbersome synthesis problems.
Abstract: By taking inspiration from (1), a synthesis strategy is proposed for the case of planar arrays and ring shaped patterns which does not require the exploitation of global optimization procedures. In particular, the approach is able to determine a priori (that is, without solving the overall design problem) whether the given power pattern design constraints can be fulfllled or not, and, in the adflrmative case, to determine the needed excitation coe-cients in a fast deterministic manner. Although the approach does not apply to generic planar arrays and generic constraints, it applies to a large number of problems of actual interest, and outperforms some recently published synthesis procedures. Moreover, it may serve both as a reference solution for more general synthesis procedures, and as an elementary brick for more cumbersome synthesis problems.

Journal Article
TL;DR: A new scheme, the acceleration clipping, is introduced, which enhances CFO's global search ability while maintaining its simplicity, and is applied to the optimal design of two difierent wideband microstrip patch antennas.
Abstract: Central force optimization (CFO) is a new simple deterministic multi-dimensional search evolutionary algorithm (EA) inspired by gravitational kinematics. This paper evaluates CFO's performance and provides further examples on its efiectiveness. A new scheme, the acceleration clipping, is introduced, which enhances CFO's global search ability while maintaining its simplicity. The improved CFO algorithm is applied to the optimal design of two difierent wideband microstrip patch antennas. Speciflcally, a microstrip line fed E-shaped patch antenna and a coaxial line fed double-E-shaped patch antenna are designed and optimized using the CFO method. CFO's performance on these antennas is compared to that of the difierential evolution (DE) optimization. Both the CFO and DE methods are interfaced with the full-wave IE3D software. It is found that the CFO results are very close to those obtained using the DE technique.