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Antenna Elements (antenna + element)
Selected AbstractsVery small aperture terminal broadband shared-aperture planar antennasINTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 3 2003N. C. Karmakar Abstract The design and development of a shared-aperture dual-band, dual-polarized, dual-aperture coupled rectangular microstrip patch antenna element is presented, which is suitable for portable very small aperture terminals. Detailed parametric studies of the locations of orthogonal coupling slots and their influences on the isolation and impedance bandwidth of the antenna element are performed. The experimental results are presented. The prototype dual-band dual-polarized antenna element achieves a 21% input impedance bandwidth at the S- and C-bands. The design and development of a four-element array with such an antenna element is also presented. © 2003 Wiley Periodicals, Inc. Int J RF and Microwave CAE 13: 180,193, 2003. [source] Multiband MIMO antenna with independent resonance frequency adjustabilityMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 8 2010Min-Seok Han Abstract A compact multiband multiple-input multiple-output (MIMO) antenna with a band stop matching circuit for next generation mobile applications is proposed. The proposed multiband MIMO antenna consists of two dual-band planar inverted-F antennas, which provide wideband characteristics. To improve the isolation characteristic at the long term evolution band, a band stop matching circuit was inserted at the corner of each antenna element. The proposed MIMO antenna has isolation of ,15 dB at the lower band and over 20 dB at the upper band. In addition, the resonant frequencies of the proposed MIMO antenna can be independently tuned by changing the value of the inductor or by adjusting the widths of Slit1 and Slit2. To evaluate the performance of the proposed antenna, key performance parameters such as total efficiency, envelope correlation coefficient, mean effective gain (MEG), and the MEG ratio are analyzed. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1893,1901, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25334 [source] Compact dual-band multilayer antenna element for nonlinear junction detector applicationMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 3 2009Krzysztof Wincza Abstract A compact dual-band antenna element for application in a nonlinear junction detector is proposed. To achieve broadband characteristics in two separate frequency ranges a stratified structure is proposed in which two driven and two parasitic patches are properly placed. For transmitting, a circularly polarized antenna is used in which stacked square ring resonators are applied to achieve simultaneously broadband operation and compact size. For receiving, a dual-polarized antenna is proposed in which a square patch is loaded by a square ring resonator to provide wide band and to allow for integration with the transmitting antenna. Theoretical calculations confirmed by measurement results are presented. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 696,699, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24136 [source] A pattern-reconfigurable microstrip antenna elementMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 6 2006K. W. Lee Abstract A novel radiation-pattern-reconfigurable circularly polarized microstrip antenna structure is presented. The measured results show that the antenna is able to provide a magnitude difference of more than 6 dB at 90° from broadside (in two principal planes) for the tangential (to the antenna surface) field component between the on and off states of the switches. Nonetheless, the vertical field component remains relatively unchanged. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1117,1119, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21555 [source] A K-band inverted microstripline-fed linear tapered slot antenna and its 16-element E-plane arrayMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 3 2005Chen Wu Abstract An inverted microstripline-fed linear tapered slot antenna element and a design of its 16-element E-plane array are presented in this paper. The element is designed using the finite-difference time-domain (FDTD) method. The calculated results show that it has a wide-impedance bandwidth in the K-band. To investigate the E-plane array, the return loss at each element input port, the couplings among elements, and the array's radiation patterns are obtained using the FDTD method. Using a unique three-piece assembled structure, the array is fabricated and tested experimentally. The measured results show that it has a wide bandwidth and antenna efficiency. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 45: 241,246, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20784 [source] Dual-frequency and dual-polarization multilayer microstrip antenna elementMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 4 2004Georgios Ch. Abstract A dual-frequency and dual-linear polarization multilayer microstrip antenna element for array-antenna applications is presented. The performance of the element was computed using a commercial software based on the finite-element-method (FEM) algorithm. A prototype with dimensions based on the simulations was built and tested. Good agreement between the measured and numerical results is obtained. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 311,315, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20288 [source] Exploiting the short,term and long,term channel properties in space and time: Eigenbeamforming concepts for the BS in WCDMAEUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 5 2001Christopher Brunner The deployment of adaptive antennas at base stations considerably increases the spectral efficiency of wireless communication systems. To reduce the computational complexity and increase performance of space,time (ST) processing, processing may take place in reduced dimension, i. e., pre,filtering takes place which is related to linear estimation theory based on second order statistics. To this end, long,term and short,term channel estimates are integrated into specific Tx/Rx systems. In this article, we present a new ST rake structure for uplink reception in WCDMA which operates in reduced dimension. Accordingly, our approach combines short,term and long,term spatial and temporal channel properties using an eigenanalysis. By choosing dominant eigenbeams in time and space, the algorithm enhances interference suppression as well as spatial and temporal receive diversity. In contrast to previously introduced well,known receiver structures, the ST eigenrake inherently adapts to different propagation environments and achieves higher spectral efficiency than other receivers. This is illustrated by Monte,Carlo simulations. Then we extend the proposed concept to the downlink. The downlink eigenbeamformer improves closed,loop downlink diversity compared to other proposals in standardization (3GPP) which only exploit short,term channel properties. Even though the short,term feedback rate remains unchanged, additional antenna elements can be included to increase antenna and diversity gain. We also present a tracking solution to the downlink eigenbeamforming in WCDMA. To this end, we propose a distributed implementation of the eigenspace/,beam tracking at the mobile terminal and base station (BS), respectively. Moreover, the specific nature of the deployed tracking scheme offers an advantageous feedback signalling. [source] Fractionally spaced spatial adaptive equalization of S-UMTS mobile terminals,INTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 8 2002Jörgen Nordberg Abstract In this paper we present fractionally spaced adaptive equalization techniques and space diversity combined receiver and evaluate their performance for the downlink of S-UMTS system. The conventional ,training' (or non-blind) and the ,unsupervised' (or blind) adaptive equalization algorithms are both investigated. Simulation results show that the equalizers are robust to Doppler shift and non-linearity effects due to TWT amplifiers aboard the satellite. It is also shown that even with a moderate array size of two antenna elements, a significant improvement in terminal performance is achieved. Copyright © 2002 John Wiley & Sons, Ltd. [source] Planar ultrawideband antenna array for short-range wireless communicationsMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 5 2010Osama 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] Low profile DOA finder at 2.4 GHzMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 1 2009M. 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 characterizationMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 12 2008Ying-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] A novel internal antenna with high gain for wireless phoneMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 9 2007Ying Liu Abstract A novel internal antenna for synchronous code division multiple access band wireless phone is presented. Traditional internal antenna is monopole or Planar Inverted-F Antenna, which have no gain high enough in the limited space in phone. The proposed antenna is composed of two antenna elements with equal magnitude and 180° phase difference, to assure voice quality with high gain. The measured maximum gain is 2.69 dBi and maximum efficiency is 70.1% in the frequency band 450,470 MHz. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2112,2114, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22708 [source] Wide coverage area of UHF-band RFID system using a pattern reconfigurable antennaMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 9 2007Hanphil Rhyu Abstract A new type of a reader antenna for a UHF-band RFID system is proposed to cover a wider area. The proposed antenna consists of a circular polarized patch element, an omnidirectional electrical loop element, and a feeding network. By combining two antenna elements whose radiation patterns and half-power beamwidths (HPBW) are different from each other, the coverage area of the RFID system is increased. The experimental results show the proposed antenna has a HPBW of more than 120° and works well in the UHF band RFID system. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2154,2157, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22694 [source] A dual-band antenna design for GPS and UMTS applicationsMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 8 2007Chow-Yen-Desmond Sim Abstract The design of an integrated dual-band antenna for global positioning system (GPS) and universal mobile telecommunications system (UMTS) is presented. A circularly polarized square-ring corner truncated microstrip antenna is designed for GPS application, and a monopolar shorted square patch antenna embedded within the center of the square-ring is designed for UMTS application. Both proposed antenna elements demonstrated desirable isolation, radiation pattern; polarization, and bandwidth requirement. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1935,1939, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22597 [source] Scanning properties of sequentially rotated linear arrays of circularly polarized patch radiatorsMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 5 2001Quiterio García-García Abstract This paper presents a theoretical analysis of the effect of beam scanning and amplitude tapering on the cross-pol level of sequentially rotated linear arrays composed of circularly polarized patch antenna elements. Arrays of eight elements are considered to illustrate the analysis. Several sequential phase distributions are analyzed in terms of the cross-pol level cancellation effect over the antenna field of view. These arrangements are analyzed in terms of the location of the maximum cross-pol peak levels and their values. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 343,350, 2001. [source] | ||||||||||