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Antenna Array (antenna + array)

Distribution by Scientific Domains
Engineering93%

Kinds of Antenna Array

  • microstrip antenna array
    		•

    Selected Abstracts

    Fuzzy-based multiuser detector for impulsive CDMA channel

    EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 7 2007
    Adel M. Hmidat
    A new fuzzy multiuser detector for non-Gaussian synchronous direct sequence code division multiple access (DS-CDMA) is proposed for jointly mitigating the effects of impulsive noise and multiple access interference (MAI). The proposed scheme combines a linear decorrelator and antenna array with a nonlinear preprocessor based on fuzzy logic and rank ordering. The fuzzy rule is incorporated to combat impulsive noise by eliminating outliers from the received signal. The performance of the proposed scheme is assessed by Monte Carlo simulations and the obtained results demonstrate that the proposed fuzzy detector outperforms other reported schemes in terms of bit error rate (BER) and channel capacity. Copyright © 2007 John Wiley & Sons, Ltd. [source]

    Adaptive joint beamforming and B-MMSE detection for CDMA signal reception under multipath interference

    INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 7 2004
    Hsiao-Hwa Chen
    Abstract The combination of antenna array beamforming with multiuser detection can effectively improve the detection efficiency of a wireless system under multipath interference, especially in a fast-fading channel. This paper studies the performance of an adaptive beamformer incorporated with a block-wise minimum mean square error(B-MMSE) detector, which works on a unique signal frame characterized by training sequence preamble and data blocks segmented by zero-bits. Both beam-former weights updating and B-MMSE detection are carried out by either least mean square (LMS) or recursive least square (RLS) algorithm. The comparison of the two adaptive algorithms applied to both beamformer and B-MMSE detector will be made in terms of convergence behaviour and estimation mean square error. Various multipath patterns are considered to test the receiver's responding rapidity to changing multipath interference. The performance of the adaptive B-MMSE detector is also compared with that of non-adaptive version (i.e. through direct matrix inversion). The final performance in error probability simulation reveals that the RLS/B-MMSE scheme outperforms non-adaptive B-MMSE by 1,5 dB, depending on the multipath channel delay profiles of concern. The obtained results also suggest that adaptive beamformer should use RLS algorithm for its fast and robust convergence property; while the B-MMSE filter can choose either LMS or RLS algorithm depending on antenna array size, multipath severity and implementation complexity. Copyright © 2004 John Wiley & Sons, Ltd. [source]

    Experimental studies of direction of arrivals using a smart antenna testbed in wireless communication systems

    INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 3 2003
    Shiann-Shiun Jeng
    Abstract This paper presents some preliminary results from experimental studies on space-division-multiple-access (SDMA) for wireless communications. A smart antenna system utilizing direction-of-arrival (DOA)-based beamforming techniques can enhance signal quality by reducing co-channel interference from mobiles located at angles spatially distinct from the base station. Adopting both smart uplink and downlink beamforming, a communication system with an antenna array can increase the cell coverage of a base station and significantly boost capacity compared with conventional antenna systems. However, successful implementation of DOA-based beamforming techniques depends on the DOA characteristics. This paper presented the feasibility of direction finding and DOA variation with respect to frequency. Furthermore, the angle spread was studied for selected environments. The results demonstrate the feasibility of applying proposed smart antenna system utilizing DOA-based beamforming algorithm for increasing channel capacity and improving system performance in frequency-division-duplex (FDD) wireless communication systems. Copyright © 2003 John Wiley & Sons, Ltd. [source]

    Adaptive integral method combined with the loose GMRES algorithm for planar structures analysis

    INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 1 2009
    W. Zhuang
    Abstract In this article, the adaptive integral method (AIM) is used to analyze large-scale planar structures. Discretization of the corresponding integral equations by method of moment (MoM) with Rao-Wilton-Glisson (RWG) basis functions can model arbitrarily shaped planar structures, but usually leads to a fully populated matrix. AIM could map these basis functions onto a rectangular grid, where the Toeplitz property of the Green's function would be utilized, which enables the calculation of the matrix-vector multiplication by use of the fast Fourier transform (FFT) technique. It reduces the memory requirement from O(N2) to O(N) and the operation complexity from O(N2) to O(N log N), where N is the number of unknowns. The resultant equations are then solved by the loose generalized minimal residual method (LGMRES) to accelerate iteration, which converges much faster than the conventional conjugate gradient method (CG). Furthermore, several preconditioning techniques are employed to enhance the computational efficiency of the LGMRES. Some typical microstrip circuits and microstrip antenna array are analyzed and numerical results show that the preconditioned LGMRES can converge much faster than conventional LGMRES. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009. [source]

    Circularly polarized space-fed microstrip antenna arrays

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 10 2010
    Rahul Bhide
    Abstract A high-gain circularly polarized microstrip antenna array is proposed using space-fed configuration. In planar arrays, the design of feed network to generate circular polarization becomes extremely complex. The proposed configuration eliminates the feed network, which gives high efficiency and gain. Simulated and measured results are presented. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2221,2223, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25451 [source]

    Efficient and high-gain aperture coupled superstrate antenna arrays for 60 GHz indoor communication systems

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 10 2010
    Hamsakutty Vettikalladi
    Abstract Efficient and high-gain aperture coupled patch antenna arrays with superstrate at 60 GHz are studied and presented. It is noted that adding a superstrate with a specific size will induce a significant effect on antenna gain and radiation patterns. This capability is applied on the design of 2 × 2 and 4 × 4 arrays for high-gain application. The maximum measured gain of a 2 × 2 superstrate antenna array is 16 dBi with an efficiency of 63%, which is 4 dB higher than that of a classical 2 × 2 array at 60 GHz. The 2:1 measured voltage standing wave ratio (VSWR) bandwidth is 6.8%. Also the maximum gain measured for a 4 × 4 superstrate antenna array is found to be 19.7 dBi with an estimated efficiency of 51%. The radiation patterns are found to be broadside all over the frequency band with very low back radiation. Hence aperture coupled superstrate antenna array is a good candidate for high-efficient high-gain application at 60 GHz. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2352,2356, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25455 [source]

    Planar ultrawideband antenna array for short-range wireless communications

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 5 2010
    Osama M. H. Ahmed
    Abstract In this article, novel 2-element and 4-element planar ultrawideband (UWB) antenna arrays with bidirectional radiation patterns based on identical UWB antenna elements for UWB communications applications have been proposed, simulated and experimentally investigated. Each array is constructed by means of feeding omni-directional printed UWB monopole antennas with a UWB power divider. The proposed 2-element antenna array yields an impedance bandwidth of 110% (3.1,10.6 GHz) covering the whole UWB frequency bandwidth while the impedance bandwidth is multi-band in case of the 4-element antenna array because of the increasing effect of mutual coupling among antenna elements. The calculated gain of the 2-element and 4-element array is quite stable with about 3 and 6 dB higher than that of the single element, respectively. Both measured and calculated E-plane radiation patterns of the array and the single element are almost the same while the H-plane radiation patterns of the array are distinctively bidirectional compared to the omni-directional pattern of the single element. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1061,1066, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25140 [source]

    Substrate-integrated-waveguide feed network for microstrip antenna arrays

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 7 2009
    Mohsen Yousefbeigi
    Abstract In this article, a low-loss parallel-series feed structure using substrate integrated waveguide (SIW) technology for a single-layer microstrip antenna array is presented. In addition to reduction of feed radiation, the feed network benefits from typical advantages of planar structures such as compactness, low cost, integrability, and mass-producibility. A 2 × 8 microstrip antenna array of size 109 mm × 34 mm fed by the proposed SIW feed system is designed and fabricated. Measurements on the fabricated array verify a minimum gain of 17.5 dBi in the frequency range of 17.4 to 18 GHz. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1619,1621, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24412 [source]

    A wideband circularly polarized microstrip antenna array with single feeding

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 7 2009
    Ping Yao
    Abstract In this article, one wideband circularly polarized microstrip antenna array has been proposed and investigated. The technique of sequential rotation subarray has been employed to construct the whole antenna array, which enhances the impedance bandwidth and axial ratio (AR) bandwidth by 54.65 and 220.93%, respectively, when compared with the traditional way of CP array formation. One 8 × 4 antenna array has been fabricated and measured, agreement can be observed between the experimental and simulation results, the measured VSWR bandwidth is 7.33%, the AR bandwidth is 4.31%, and the gain is about 19 dB. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1624,1627, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24438 [source]

    A compact dual-element antenna array for adaptive MIMO system

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 2 2009
    Xuan Wang
    Abstract A novel compact dual-element antenna array is proposed for adaptive MIMO system. By four embedded PIN diodes in the feeding network, the antenna array has three different working states. It can operate as a dual-element antenna array or work as a single antenna while the unselected antenna is terminated to a lumped matched resistor. As a dual-element antenna array, it has a ,10 dB impedance bandwidth of 595 MHz covering UMTS band with mutual coupling lower than ,15 dB in the whole band. The measured radiation patterns show that the radiation property of the selected antenna keeps steady no matter the other antenna is selected or not. The proposed antenna array can achieve antenna selection scheme to adapt to the time-varying channel conditions. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 348,351, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24044 [source]

    Low profile DOA finder at 2.4 GHz

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 1 2009
    M. Uthansakul
    Abstract Technique to find direction of arrival (DOA) has been promisingly constructed by smart antenna technology. It consists of array antennas and signal processing unit. Because of the limitation of space in commercial products, the size of antenna array should be designed with the smallest dimension. Also the processing unit is expected in low complexity and expense. Most of DOA finders were recently proposed employing linear array in which the size is linearly increased as a number of antenna elements. Also the processing units were fully comprised with high level of computation. In this paper, the low profile of 2.4 GHz DOA finder is proposed. The DOA finder is designed in the compact size of 2 × 2 array antennas. Using modified Butler matrix, the processing unit is very simple in which it can be handled by any economic microprocessors. The proposed finder is able to delicately specify DOA in every angle from 0° to 360°. The experimental results confirm the success of proposed DOA finder. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 252,256, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23984 [source]

    Planar 4-element UWB antenna array and time domain characterization

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 12 2008
    Ying-Ying Yang
    Abstract In this article, a novel planar ultra-wideband (UWB) antenna array based on four identical UWB antenna elements for UWB applications is presented. The proposed antenna array yields an impedance bandwidth of 3.1,10.6 GHz with VSWR <2. Over the entire bandwidths, it has constant high gain, which is about 6.5,10.5 dBi, and a 60° 3-dB beamwidth is obtained within the operational band. A planar 2-element UWB antenna array and a band-notched 4-element UWB antenna array are also provided for references. Time domain descriptors of the proposed antenna array have been used to estimate short-range UWB signal transmission, propagation, and reception. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 3118,3123, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23874 [source]

    Segmented analysis of a finite planar ridged tapered slot antenna array for wideband phased array

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 5 2008
    Junyeon Kim
    Abstract The segmented analysis method of a finite planar ridged tapered slot antenna (RTSA) array is presented to develop a wideband phased array with a triangular lattice. The RTSA array is segmented into two-parts with a feeder and the arrays of tapered slot antenna (TSA) and these scattering parameters are analyzed respectively. This proposed method gives the merit of a great reduction of computational cost. To verify the advantage of this method, we build the numerical model of only one feeder and dual polarized arrays of TSA with 10 × 12 elements. The measured results of the fabricated array meet the design goals of 3:1 bandwidth, scan volume of ±45°, active VSWR (AVSWR) below 3:1. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1140,1143, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23314 [source]

    Improving the radiation characteristics of a base station antenna array using a particle swarm optimizer

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 7 2007
    Z. D. Zaharis
    Abstract A particle swarm optimization based technique is applied on linear antenna arrays used by broadcasting base stations. Both the geometry and the excitation of the antenna array are optimized by a suitable algorithm under the constraints of the maximum possible gain at the desired direction and the desired value of side lobe level. The matching condition of the elements of the antenna array is also required by the algorithm. The technique has been applied to antenna arrays composed of collinear wire dipoles and seems to be very promising for improving radiation patterns of base station antenna arrays in many practical applications. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1690,1698, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22505 [source]

    A wideband low-profile microstrip antenna and array

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 4 2006
    Ka-Ming Mak
    Abstract A high-gain wideband low-profile microstrip patch antenna array is designed and tested. A method for enhancing the impedance bandwidth through the combination of a driven rectangular patch with parasitic elements is proposed. The array, which has 16 elements in a 4 × 4 arrangement, is pasted on a 2-mm dielectric substrate. The impedance bandwidth and the gain of the array is 12% (for SWR , 2) centered at 4.5 GHz and 20 dBi, respectively. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 729,730, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21458 [source]

    Nonuniform dual band array with optimum side-lobe levels

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 3 2006
    Asha E. Daniel
    Abstract A linear symmetric stub-loaded dual-band rectangular microstrip antenna array (RMSA array) with nonuniform interelement spacing has been proposed for reduced side-lobe levels at both resonant frequencies. The interelement spacing has been optimized using a gradient search algorithm. It is observed that the side-lobe level reduces as a function of the number of elements. The predicted radiation patterns have been verified experimentally. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 615,617, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21424 [source]

    Wafer-scale silicon optically controlled absorber/reflector surface

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 4 2005
    V. Fusco
    Abstract A wafer-scale silicon optically controlled wafer antenna array, which can be used to reflect or absorb incident microwave energy at 10 GHz, is presented. A 2-,m-thick copper printed dipole array, loaded with matched polysilicon resistive terminations, is fabricated on a 4-inch-high resistivity, 6k,-cm, 525-,m-thick silicon wafer. A second unprocessed wafer, optically controlled by an optical source, provides a shutter mechanism so that the assembly acts as a reflector/absorber surface or spatial switch. The arrangement is shown to provide 25-dB isolation between reflecting and absorbing states at 10.1 GHz. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 44: 318,320, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20622 [source]

    Stepped frequency ground-penetrating radar survey with a multi-element array antenna: Results from field application on archaeological sites,

    ARCHAEOLOGICAL PROSPECTION, Issue 3 2010
    Neil Linford
    Abstract A series of trial geophysical surveys were conducted with a 3d-Radar GeoScope ground-penetrating radar (GPR) utilizing a multi-element array antenna. This system offers the potential for rapid data acquisition at very high sample densities over a wide frequency bandwidth. Field tests, conducted over the Roman town at Silchester, Hampshire, UK, suggested that a revised antenna configuration was necessary to obtain optimum results from the system, which was then successfully deployed in the collection of over 5,ha of survey data at a sample density of 0.075,m,×,0.075,m. The wide area survey produced a wealth of archaeological detail to complement and expand upon the extensive record of excavation, aerial photography and other geophysical results. Initial trial surveys were conducted with a range of antenna arrays (B2431, B1831 and B1823) incorporating different sized elements to fully exploit the wide potential bandwidth of the system. However, the differing response of elements proved difficult to combine within a single data set and a marked increase in quality was obtained with the use of a prototype V1821 antenna array of identical sized elements. Some concerns remain regarding both the suitability of air-launched antenna arrays to certain site conditions, as one early survey visit to Silchester produced very poor results that remain unexplained, and the maximum penetration depth compared with an impulse GPR using ground-coupled antenna. © 2010 Crown copyright. [source]

    Fixed relaying with adaptive antenna arrays for the downlink of multihop cellular networks

    EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 2 2010
    Zaher Dawy
    Multihop cellular networks are expected to play an important role in the evolution towards 4G. In this work, we propose the use of advanced antenna techniques (adaptive antenna arrays and directional antennas) at fixed relay stations in order to enhance the downlink performance of multihop cellular networks. The performance gains of various adaptive antenna configurations are analytically studied by introducing a new system-level parameter called the interference reduction factor. Moreover, Monte-Carlo simulation results as a function of various design parameters are presented and analysed in order to further highlight the gains of advanced antenna techniques. Based on the presented analysis, we propose the use of a hybrid antenna configuration at relay stations in order to obtain high gains with limited increase in complexity and cost. Copyright © 2010 John Wiley & Sons, Ltd. [source]

    Amplitude-only pattern nulling of linear antenna arrays with the use of an immune algorithm

    INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 5 2008
    Kerim Guney
    Abstract This article presents an optimization immune algorithm (opt-IA) for null steering of linear antenna arrays by controlling only the element amplitudes. Nulling of the pattern is also achieved by controlling the phase-only and the complex weights (both the amplitude and phase) of the array elements. The opt-IA is a new evolutionary computing algorithm based on the clonal selection principle of immune system. To show the accuracy and flexibility of the proposed opt-IA, several examples of Chebyshev array pattern with the imposed single, multiple, and broad nulls are given. It is found that the nulling technique based on opt-IA is capable of steering the array nulls precisely to the undesired interference directions. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2008. [source]

    EM design of broadband RF multiport toggle switches

    INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 4 2004
    W. Simon
    Abstract Radio frequency (RF) MEMS is an emerging sub-area of MEMS technology that is revolutionizing RF and microwave applications. RF MEMS devices have a broad range of optional applications in military and commercial wireless communication, and navigation and sensor systems. This article presents the EM design of different multiport toggle switches. Such a multiport switch can be used in the compact designs of switching matrices, routing networks, or phase shifters. One application range is the creation of electronically steerable antenna arrays, which can be used for radar applications and satellite communication. The miniaturized switches are based on the single pole single throw (SPST) toggle switch and, in addition to their small size, they have an increased RF performance regarding losses and operation bandwidth (DC to 50 GHz). A 3D FDTD field solver has been used for the electromagnetic design of all the switches. © 2004 Wiley Periodicals, Inc. Int J RF and Microwave CAE 14: 329,337, 2004. [source]

    Noise in lossless microwave multiports

    INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 2 2004
    Q. García-García
    Abstract This article addresses the noise behaviour (noise temperature and noise figure) of some passive microwave multiport circuits. The analysis method is based on the noise-wave formulation. With the exception of the attenuator case, which is used as a reference, the circuit elements considered are lossless devices, in the sense that neither conductive nor dielectric losses are accounted for. The analysis shows that, when connected to matched loads in some of their ports, these multiports circuits lose their lossless nature and their scattering matrix is not unitary; therefore, they generate thermal noise. The article addresses and formalizes mathematically the noise properties of a number of lossless microwave devices such as N -port power splitters, circulators, and hybrid couplers. While the noise-wave mathematical formulation may be cumbersome in some cases, all the devices and configurations analyzed in this work have been characterized in terms of noise figure and noise temperature, which is a much more practical approach in most situations. Some implications of the use of these devices and configurations in antenna arrays for antenna noise temperature evaluations have been also addressed. © 2004 Wiley Periodicals, Inc. Int J RF and Microwave CAE 14, 99,110, 2004. [source]

    Single elements for low cost planar antenna arrays for consumer applications beyond 100 GHz

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 12 2010
    Pablo Herrero
    Abstract Single planar element designs working at frequencies around 122 GHz are presented. The structures are designed keeping in mind future commercial applications that might arise in mm-wave bands. Therefore, structures are explored with different radiation patterns. The antennas are implemented using commercial substrate and common photolithography to meet low cost requirements of consumer applications. Matching and radiation pattern was measured showing very good agreement simulations. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2685,2688, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25563 [source]

    Circularly polarized space-fed microstrip antenna arrays

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 10 2010
    Rahul Bhide
    Abstract A high-gain circularly polarized microstrip antenna array is proposed using space-fed configuration. In planar arrays, the design of feed network to generate circular polarization becomes extremely complex. The proposed configuration eliminates the feed network, which gives high efficiency and gain. Simulated and measured results are presented. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2221,2223, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25451 [source]

    Efficient and high-gain aperture coupled superstrate antenna arrays for 60 GHz indoor communication systems

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 10 2010
    Hamsakutty Vettikalladi
    Abstract Efficient and high-gain aperture coupled patch antenna arrays with superstrate at 60 GHz are studied and presented. It is noted that adding a superstrate with a specific size will induce a significant effect on antenna gain and radiation patterns. This capability is applied on the design of 2 × 2 and 4 × 4 arrays for high-gain application. The maximum measured gain of a 2 × 2 superstrate antenna array is 16 dBi with an efficiency of 63%, which is 4 dB higher than that of a classical 2 × 2 array at 60 GHz. The 2:1 measured voltage standing wave ratio (VSWR) bandwidth is 6.8%. Also the maximum gain measured for a 4 × 4 superstrate antenna array is found to be 19.7 dBi with an estimated efficiency of 51%. The radiation patterns are found to be broadside all over the frequency band with very low back radiation. Hence aperture coupled superstrate antenna array is a good candidate for high-efficient high-gain application at 60 GHz. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2352,2356, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25455 [source]

    Planar ultrawideband antenna array for short-range wireless communications

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 5 2010
    Osama M. H. Ahmed
    Abstract In this article, novel 2-element and 4-element planar ultrawideband (UWB) antenna arrays with bidirectional radiation patterns based on identical UWB antenna elements for UWB communications applications have been proposed, simulated and experimentally investigated. Each array is constructed by means of feeding omni-directional printed UWB monopole antennas with a UWB power divider. The proposed 2-element antenna array yields an impedance bandwidth of 110% (3.1,10.6 GHz) covering the whole UWB frequency bandwidth while the impedance bandwidth is multi-band in case of the 4-element antenna array because of the increasing effect of mutual coupling among antenna elements. The calculated gain of the 2-element and 4-element array is quite stable with about 3 and 6 dB higher than that of the single element, respectively. Both measured and calculated E-plane radiation patterns of the array and the single element are almost the same while the H-plane radiation patterns of the array are distinctively bidirectional compared to the omni-directional pattern of the single element. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1061,1066, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25140 [source]

    Substrate-integrated-waveguide feed network for microstrip antenna arrays

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 7 2009
    Mohsen Yousefbeigi
    Abstract In this article, a low-loss parallel-series feed structure using substrate integrated waveguide (SIW) technology for a single-layer microstrip antenna array is presented. In addition to reduction of feed radiation, the feed network benefits from typical advantages of planar structures such as compactness, low cost, integrability, and mass-producibility. A 2 × 8 microstrip antenna array of size 109 mm × 34 mm fed by the proposed SIW feed system is designed and fabricated. Measurements on the fabricated array verify a minimum gain of 17.5 dBi in the frequency range of 17.4 to 18 GHz. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1619,1621, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24412 [source]

    On the sources reconstruction method application for array and aperture antennas diagnostics

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 7 2009
    Fernando Las-Heras
    Abstract This article presents two practical applications of the Sources Reconstruction Method for antenna diagnostics and antenna manufacturing errors detection. The goal is to show the SRM capabilities to determine defective elements in antenna arrays as well as to detect irregularities in the surface of reflector antennas from the analysis of the aperture fields. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1664,1668, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24416 [source]

    Improving the radiation characteristics of a base station antenna array using a particle swarm optimizer

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 7 2007
    Z. D. Zaharis
    Abstract A particle swarm optimization based technique is applied on linear antenna arrays used by broadcasting base stations. Both the geometry and the excitation of the antenna array are optimized by a suitable algorithm under the constraints of the maximum possible gain at the desired direction and the desired value of side lobe level. The matching condition of the elements of the antenna array is also required by the algorithm. The technique has been applied to antenna arrays composed of collinear wire dipoles and seems to be very promising for improving radiation patterns of base station antenna arrays in many practical applications. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1690,1698, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22505 [source]

    Analysis, synthesis, and diagnostics of antenna arrays through complex-valued neural networks

    MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 8 2006
    J. C. Brégains
    Abstract It is shown in this paper that when artificial neural networks are extended to be complex valued, they can be incorporated as a very powerful and effective tool in the analysis, synthesis, and diagnostics of antenna arrays. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1512,1515, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21706 [source]