By Topic

Antennas and Wireless Propagation Letters, IEEE

Volume 7: 2008

Filter Results

Displaying Results 1 - 25 of 216
  • Blank page [back cover]

    Publication Year: 2008 , Page(s): C4
    Save to Project icon | Request Permissions | PDF file iconPDF (5 KB)  
    Freely Available from IEEE
  • Blank page [back cover]

    Publication Year: 2008 , Page(s): C4
    Save to Project icon | Request Permissions | PDF file iconPDF (5 KB)  
    Freely Available from IEEE
  • IEEE copyright form

    Publication Year: 2008 , Page(s): 847 - 848
    Save to Project icon | Request Permissions | PDF file iconPDF (1065 KB)  
    Freely Available from IEEE
  • 2008 Index IEEE Antennas and Wireless Propagation Letters Vol. 7

    Publication Year: 2008 , Page(s): 811 - 840
    Save to Project icon | Request Permissions | PDF file iconPDF (254 KB)  
    Freely Available from IEEE
  • 2008 List of Reviewers

    Publication Year: 2008 , Page(s): 808 - 810
    Save to Project icon | Request Permissions | PDF file iconPDF (31 KB)  
    Freely Available from IEEE
  • Comments on 'Pair-Matching Method for Estimating 2-D Angle of Arrival With a Cross-Correlation Matrix'

    Publication Year: 2008 , Page(s): 807
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (45 KB) |  | HTML iconHTML  

    Summary form only given: This paper proposed a new pair-matching method which is suitable for the signal impinged on the array from direction at elevation angle thetas and azimuth angle Phi. This new method exploits the cross-correlation matrix of two received signals impinging on two uniform linear arrays (ULAs). However this method is valid only in some specific directions of the impinging signals. To refine the work presented in paper, we have made the following comments. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A Spiral-Dipole Antenna for MIMO Systems

    Publication Year: 2008 , Page(s): 803 - 806
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1187 KB) |  | HTML iconHTML  

    A new circular polarization spiral-dipole antenna has been proposed for multilple-input-multiple-output (MIMO) systems. A dipole antenna is loaded with spirals at both of its ends to generate omnidirectional left-hand or right-hand circular polarization. The sense of polarization [left-hand circular polarization (LHCP) or right-hand circular polarization (RHCP)] depends on the orientation of the spirals. The measured bandwidth of the antenna is 8% at the center frequency of 5.2 GHz with 3.6-dBic gain. The isolation ( S 21) between collocated LHCP and RHCP antennas is better than 30 dB that makes them suitable for MIMO. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Efficient Method of DOA Estimation for Uncorrelated and Coherent Signals

    Publication Year: 2008 , Page(s): 799 - 802
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (194 KB) |  | HTML iconHTML  

    In this letter, an efficient direction-of-arrival (DOA) estimation method is proposed with a uniform linear array when uncorrelated and coherent signals coexist. The method can effectively eliminate the possible false DOA estimates of uncorrelated signals, and only the true DOA estimates can be retained. After estimating the DOAs and power of uncorrelated signals, the information in them can be eliminated from the signal subspace. Then, we can obtain a matrix that only contains the information of coherent signals, which we call the C-matrix. Finally, the coherent signals are resolved with a new constructed matrix by the C-matrix. The theoretical analysis and simulation results confirm the effectiveness of our proposed method. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Genetic-Algorithm-Based Antenna Array Design for a 60-GHz Hybrid Smart Antenna System

    Publication Year: 2008 , Page(s): 795 - 798
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (640 KB) |  | HTML iconHTML  

    The previously described hybrid smart-antenna system solves the transmitter receiver alignment problem of 60-GHz wireless systems when high gain antennas are used. Utilizing multiple highly directional array elements and coherently combining the outputs of a few elements adaptively, the hybrid smart antenna achieves the desired performance and results in significant hardware cost and computational complexity savings. For optimal alignment, however, the output power of the hybrid smart antenna should stay constant over the scanning range. This minimizes the so-called scalloping effects and necessitates a careful selection of the array elements being used in beamforming. In this letter, a genetic-algorithm solution to optimally adjust the beam pattern overlaps the array elements to minimize the output-power fluctuations in a given scan range. It is shown that while the hybrid algorithm may perform satisfactorily with less than one-third of the total number of the array elements (e.g., two or three elements in an array of ten antennas), there is an optimal number of elements for a given array that provides minimal power fluctuation in a specified scan range. A tradeoff between the acceptable level of power fluctuation and the total received power is identified. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Inverted Mode Patch Antenna for Dual-Band Communications

    Publication Year: 2008 , Page(s): 792 - 794
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (468 KB) |  | HTML iconHTML  

    In this letter, a single-port patch antenna with dual-band operation is presented. In order to provide two types of services, different radiation patterns for each band are proposed. The original aspect of the proposed design is the inverted disposition of modes compared with the short-circuited ring patches, where the resonant frequency of the zeroth-order mode is below the frequency of the first order one. In addition, the antenna is flexible for any application, because both frequencies are independent of each other. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Genetically Optimized Metasurface Pairs for Wideband Out-of-Phase Mutual Response

    Publication Year: 2008 , Page(s): 788 - 791
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (194 KB) |  | HTML iconHTML  

    This letter deals with the design of a pair of metasurfaces made of dense periodic arrays of electric dipoles laid on thin metal-backed dielectric substrates, capable of maintaining out-of-phase reflection coefficients over a wide frequency band. Our design is based on the genetic optimization of the dipole dimensions and spacings, and the substrate thickness. For performance assessment and illustration of potential applications to reduction/control of radar cross-section signatures, we present an example involving Bragg-scattering suppression in strip arrays. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An Optimization Procedure for Including the Higher Order Mode Coupling Between Coupling Slots in the Design of a Planar Slot Array

    Publication Year: 2008 , Page(s): 785 - 787
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (210 KB) |  | HTML iconHTML  

    A simple iterative procedure to account for higher order mode coupling between adjacent coupling slots of a planar slot array is presented. The method converges rapidly and is easy to implement in conjunction with Elliott's design technique for planar arrays. The procedure is illustrated with an example and validated by a full-wave moment method analysis. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Evaluation of a Double-Shell Integrated Scanning Lens Antenna

    Publication Year: 2008 , Page(s): 781 - 784
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (671 KB) |  | HTML iconHTML  

    This letter presents the design and evaluation of a high dielectric constant double-material integrated lens antenna for multibeam or scanning applications. The lens is formed by two shaped embedded shells of different material permittivity to enhance both power transmission across the lens interfaces and the lens scanning characteristics over a broad frequency range, when the feeds are integrated at the lens base. Design is based on geometrical optics formulation and the lens performance is evaluated using the classic hybrid geometrical optics/physical optics approach (GO/PO). The proposed lens concept is experimentally validated with a fabricated MACORtrade/acrylic prototype, showing less than 1-dB scan loss up to plusmn20deg with Gaussicity better than 95% over 40% frequency band at millimeter waves. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An Efficient Ladder Reflector Antenna for Interchip Communications

    Publication Year: 2008 , Page(s): 777 - 780
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (555 KB) |  | HTML iconHTML  

    A new compact 24-GHz ladder reflector antenna on chip has been developed using the standard 0.18-um six metal layers complementary metal-oxide-semiconductor (CMOS) process. The antenna consists of an active dipole and a ladder reflector array. The ladder reflector array successfully adjusts the radiation direction of the active dipole and effectively suppresses the active dipole interference to chip circuit. The measured results show that the ladder reflector antenna has a 6.25-dBdc gain at 24 GHz and a -6-dB S11 impedance bandwidth of 19.92 27.60 GHz . The design method presented in this letter is quite straightforward, and can be used to develop antenna on chip for the wireless interconnect for interchip communications. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • RFID Smart Shelf With Confined Detection Volume at UHF

    Publication Year: 2008 , Page(s): 773 - 776
    Cited by:  Papers (16)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (964 KB) |  | HTML iconHTML  

    This letter presents a smart shelf configuration for radio frequency identification (RFID) application. The proposed shelf has an embedded leaking microstrip transmission line with extended ground plane. This structure, when connected to an RFID reader, allows detecting tagged objects in close proximity with proper field confinement to avoid undesired reading of neighboring shelves. The working frequency band covers simultaneously the three world assigned RFID subbands at ultrahigh frequency (UHF). The concept is explored by full-wave simulations and it is validated with thorough experimental tests. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Dual-Band Planar Monopole Antenna for Multiband Mobile Systems

    Publication Year: 2008 , Page(s): 769 - 772
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1421 KB) |  | HTML iconHTML  

    In this letter, a simple planar monopole antenna with two operating bands for multiband mobile systems application is proposed. The proposed antenna is composed of two inverted-L branches and an open stub for impedance tuning. Both branches are resonating as quarter-wavelength monopole structures. The antenna covers the 890970-MHz and 16702350-MHz bands. A modified design for 824895-MHz and 14402180-MHz bands can be easily achieved by narrowing the widths of the lower resonant branch and the open stub. Both simulation and experimental results for the antenna characteristics are presented and discussed. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A Monopole Antenna With a Magneto-Dielectric Material and MIMO Applications

    Publication Year: 2008 , Page(s): 764 - 768
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (310 KB) |  | HTML iconHTML  

    This letter presents a monopole antenna with a magnetodielectric material and its multiple-inputmultiple-output (MIMO) applications. The proposed antenna fed by a 50-Omega coaxial line occupies a compact volume of 9.5 times 3 times 1.2 mm3 and the parameters of the magnetodielectric material as a supporter are epsiv'= 3.86 -j0.032 and mu'- jmmu' = 1.23-j0.25 at the resonant frequency. The bandwidth is 850 MHz (3.384.23 GHz) at S11< 10 dB, and the measured maximum gain is 5.57 dBi at 3.8 GHz. For evaluations of the MIMO application, the antenna has been measured in both the spherical and reverberation chamber. The microwave studio (MWS) simulation is employed for optimizing the design parameters and the simulated results are well agreed with those of the measured one. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Cavity-Backed Circularly Polarized Dual-Loop Antenna With Wide Tunable Range

    Publication Year: 2008 , Page(s): 761 - 763
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (743 KB) |  | HTML iconHTML  

    A wide-band cavity-backed dual-loop antenna for circularly polarized (CP) applications is proposed in this paper. It is differentially fed by a parallel strip line, via a transition from a microstrip line. The operating frequency band of the antenna can be tuned from 2.07 to 2.98 GHz by changing a capacitor's value in a simple matching circuit, and the bandwidth of each operating band for |S11| les -10 dB is in a range of 2.6%-4.9%. Measurements and simulations reveal that the proposed antenna features total dimensions of 1.03lambda0 in diameter and 0.26lambda0 in height (lambda0 is the free-space wavelength at the center frequency of the tunable range), AR les 3 dB and stable radiation patterns with small cross polarizations over the whole tunable frequency range. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Dual-Band Pin-Patch Antenna for Wi-Fi Applications

    Publication Year: 2008 , Page(s): 757 - 760
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (283 KB) |  | HTML iconHTML  

    The pin-patch antenna provides a low-profile monopolar element suitable for wireless access point requirements. This design concept is extended here to provide dual-band operation. Experimental results are compared to predictions from a FDTD package confirming monopolar radiation in two bands at 2.4 GHz and 5.7 GHz. This band spacing can be adjusted from 1.8:1 to more than 4:1. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A Method for Improving the Efficiency of Transparent Film Antennas

    Publication Year: 2008 , Page(s): 753 - 756
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1206 KB) |  | HTML iconHTML  

    This letter presents an optically transparent antenna, which is made of conductive AgHT coated film, with an improved efficiency by applying a highly conductive coating or metallization in the form of a very narrow strip to selective antenna areas of high current density. A measurement showed that the proposed method improved the maximum gain of a fabricated transparent antenna using the AgHT film from -5 dBi to 0 dBi at 2.2 GHz while preserving much of the optical transparency. A 3D electromagnetic model using a full-wave method of moments was developed to investigate the effect of width of the highly conductive narrow strip on the efficiency of the transparent antenna. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Electromagnetic Fields of Hertzian Dipoles in Layered Negative Refractive Index Materials

    Publication Year: 2008 , Page(s): 749 - 752
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (577 KB) |  | HTML iconHTML  

    The electromagnetic fields of a Hertzian dipole in layered negative refractive index material (NIM) are efficiently calculated using the fast all modes method (FAM) combined with the numerical modified steepest-descent path method (NMSP). The exact locations of all surface wave modes and all leaky wave modes are found for various NIM slab thicknesses. Both lossless and lossy cases are studied. It is observed that there are different types of surface wave modes or even no surface wave mode at certain slab thicknesses. The electromagnetic fields vary significantly when modes are excited or disappear at certain thicknesses. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A Stochastic Beamforming Algorithm for ESPAR Antennas

    Publication Year: 2008 , Page(s): 745 - 748
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (209 KB) |  | HTML iconHTML  

    Beamforming capabilities of ESPAR antenna structures have attracted considerable attention in recent literature. In this letter, we consider a different beamforming approach, presenting an efficient optimization algorithm which enables such antennas to create desired transmit radiation patterns in real time, rather than patterns aiming at signal to interference ratio maximization. The proposed algorithm may be used in any beamforming, diversity or multiuser system. In order to demonstrate the algorithm's efficiency, we investigate a scenario with mobile handsets equipped with ESPAR antennas, considering a beamspace multiple inputmultiple output architecture. It is shown that the algorithm may enforce even cost and size sensitive devices to efficiently operate in closed loop communication environments. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Perturbed Sierpinski Carpet Antenna With CPW Feed for IEEE 802.11 a/b WLAN Application

    Publication Year: 2008 , Page(s): 742 - 744
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (736 KB) |  | HTML iconHTML  

    A printed antenna useful for IEEE 802.11 a/b WLAN application is proposed in this letter. The antenna adopts a modified Sierpinski carpet geometry in planar monopole configuration. Design steps to achieve the desired resonance characteristics are discussed. Return loss characteristics suggest that the antenna is also suitable for HiperLAN2 system. The peak realized antenna gain is around 3.2 dBi at the lower band and 4.5 dBi at the higher band. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Small-Size Microstrip Patch Antennas Combining Koch and Sierpinski Fractal-Shapes

    Publication Year: 2008 , Page(s): 738 - 741
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (819 KB) |  | HTML iconHTML  

    A novel technique to reduce the size of microstrip patch antennas is proposed. By etching the patch edges according to Koch curves as inductive loading, and inserting the Sierpinski carpets into the patch as slot loading, it is experimentally found that the resonant frequency of the patch can be greatly lowered, and the higher the iteration order of the fractal shapes, the lower the resonant frequency becomes. And this property can be utilized to reduce the size of the microstrip patch antennas. It is also found that, the radiation patterns of the proposed fractal-shaped antennas maintained because of the self-similarity and centro- symmetry of the fractal shapes. The patches derived from this technique can find applications in integrated low-profile wireless communication systems. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Equivalent System Representation to Model the Beam Sensitivity of Receiving Antenna Arrays

    Publication Year: 2008 , Page(s): 733 - 737
    Cited by:  Papers (24)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (363 KB) |  | HTML iconHTML  

    In this letter, it is demonstrated that the beam sensitivity of an antenna array receiving system can be analyzed by using an equivalent single-channel receiver model. In this model, the antenna array is represented by an equivalent single-port antenna and the multiport active beamforming network is replaced by an equivalent two-port amplifier. Herein, the beam sensitivity is defined at the input of the receiving system and is a function of the equivalent antenna model parameters. Such a simplified representation helps us to identify the predominant factors that affect the receiver sensitivity of complex antenna array systems, without having to consider the entire system in full detail. The receiver noise is computed with the proposed model and compared to the one computed by a direct numerical method to validate its consistency. For this purpose, we consider a four-element actively beamformed dipole array with strongly coupled antenna elements causing significant noise coupling effects. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.

Aims & Scope

IEEE Antennas and Wireless Propagation Letters is devoted to the rapid electronic publication of short manuscripts in the technical areas of Antennas and Wireless Propagation.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Yang Hao
School of Electronic Engineering and Computer Science
Queen Mary College, University of London