By Topic

Antennas and Propagation, IEEE Transactions on

Issue 2 • Date Feb. 2012

Filter Results

Displaying Results 1 - 25 of 34
  • Table of contents

    Publication Year: 2012 , Page(s): C1 - 433
    Save to Project icon | Request Permissions | PDF file iconPDF (145 KB)  
    Freely Available from IEEE
  • IEEE Transactions on Antennas and Propagation publication information

    Publication Year: 2012 , Page(s): C2
    Save to Project icon | Request Permissions | PDF file iconPDF (48 KB)  
    Freely Available from IEEE
  • Guest Editorial for the Special Issue on Multiple-Input Multiple-Output (MIMO)

    Publication Year: 2012 , Page(s): 434 - 437
    Save to Project icon | Request Permissions | PDF file iconPDF (953 KB)  
    Freely Available from IEEE
  • Design of a MIMO Dielectric Resonator Antenna for LTE Femtocell Base Stations

    Publication Year: 2012 , Page(s): 438 - 444
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1470 KB) |  | HTML iconHTML  

    A novel multiple-input multiple-output (MIMO) dielectric resonator antenna (DRA) for long term evolution (LTE) femtocell base stations is described. The proposed antenna is able to transmit and receive information independently using TE and HE modes in the LTE bands 12 (698-716 MHz, 728-746 MHz) and 17 (704-716 MHz, 734-746 MHz). A systematic design method based on perturbation theory is proposed to induce mode degeneration for MIMO operation. Through perturbing the boundary of the DRA, the amount of energy stored by a specific mode is changed as well as the resonant frequency of that mode. Hence, by introducing an adequate boundary perturbation, the TE and HE modes of the DRA will resonate at the same frequency and share a common impedance bandwidth. The simulated mutual coupling between the modes was as low as - 40 dB . It was estimated that in a rich scattering environment with an Signal-to-Noise Ratio (SNR) of 20 dB per receiver branch, the proposed MIMO DRA was able to achieve a channel capacity of 11.1 b/s/Hz (as compared to theoretical maximum 2 × 2 capacity of 13.4 b/s/Hz). Our experimental measurements successfully demonstrated the design methodology proposed in this work. View full abstract»

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

    Publication Year: 2012 , Page(s): 445 - 455
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2588 KB) |  | HTML iconHTML  

    An 18-port compact antenna cube is proposed in this paper. The cube, which has a volume of 0.76 × 0.76 × 0.76 λ03, provides 18 individual channels and is ideal for multiple-input multiple-output (MIMO) wireless communications. On each of the total six faces of the cube, a three-port tri-polarization antenna is installed. All antennas adopt a metal backing configuration, so the ground of all antennas forms a well shield Faraday cage, in which other functional circuits can be installed. Experimental measurements were carried out to evaluate the performance of the antenna cube in different MIMO scenarios. The results show that MIMO systems with the proposed compact antenna cube outperform those with dipole antennas which occupy the same number of RF channels but with much larger space. When a vertical 3-dipole array, a horizontal 3-dipole array and a dual polarization antenna are used in the user end (UE), respectively, the capacity of the global selected MIMO systems with antenna cube is about 2.7, 4.6, and 2.9 bits/s/Hz more than the full MIMO systems with a vertical 3-dipole array as the access point (AP) antennas. It is 1.9, 3.9, and 2.0 bits/s/Hz more than the full MIMO systems with a vertical 5-dipole array as AP antennas. The performance differences between the MIMO systems using global and simplified selection circuits are small. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Printed MIMO-Antenna System Using Neutralization-Line Technique for Wireless USB-Dongle Applications

    Publication Year: 2012 , Page(s): 456 - 463
    Cited by:  Papers (27)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1633 KB) |  | HTML iconHTML  

    A printed two-multiple-input multiple-output (MIMO)-antenna system incorporating a neutralization line for antenna port decoupling for wireless USB-dongle applications is proposed. The two monopoles are located on the two opposite corners of the system PCB and spaced apart by a small ground portion, which serves as a layout area for antenna feeding network and connectors for the use of standalone antennas as an optional scheme. It was found that by removing only 1.5 mm long inwards from the top edge in the small ground portion and connecting the two antennas therein with a thin printed line, the antenna port isolation can be effectively improved. The neutralization line in this study occupies very little board space, and the design requires no conventional modification to the ground plane for mitigating mutual coupling. The behavior of the neutralization line was rigorously analyzed, and the MIMO characteristics of the proposed antennas was also studied and tested in the reverberation chamber. Details of the constructed prototype are described and discussed in this paper. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Simple and Efficient Decoupling of Compact Arrays With Parasitic Scatterers

    Publication Year: 2012 , Page(s): 464 - 472
    Cited by:  Papers (26)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1411 KB) |  | HTML iconHTML  

    Compact arrays such as multiple antennas on a mobile terminal suffer from low efficiency and high correlation between antenna signals. In the present paper, a simple and rigorous procedure for decoupling two closely coupled antennas with a parasitic scatterer is proposed. The parasitic scatterer, which can be an additional antenna, acts as a shield between two active antenna elements. In contrast to previous studies involving the use of parasitic scatterer for decoupling antennas, we demonstrate using antenna impedances the underlying decoupling mechanism for two arbitrary antennas. By a proper choice of parameters, perfect matching and decoupling can be obtained for a given antenna spacing without extending the overall area used, and without introducing additional decoupling networks. The price to pay is a reduction of bandwidth relative to that of widely spaced antennas, which is the case for other decoupling methods as well. Simulation and experimental results are used to substantiate the effectiveness of the proposed design approach on a two-monopole array with an antenna spacing of 0.1 wavelength. Finally, several practical considerations of the proposal are also presented, including the extension of the approach for more than two active antennas and its implementation in mobile terminals. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Reducing Mutual Coupling of MIMO Antennas With Parasitic Elements for Mobile Terminals

    Publication Year: 2012 , Page(s): 473 - 481
    Cited by:  Papers (23)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1929 KB) |  | HTML iconHTML  

    Mutual coupling is a critical problem in the design of MIMO antennas because it deteriorates the performance of MIMO systems, which not only affects the antenna efficiency but also influences the correlation. Therefore, in this paper, using parasitic elements to reduce mutual coupling is studied. By adding parasitic elements a double-coupling path is introduced and it can create a reverse coupling to reduce mutual coupling. As an example, a dual-slot-element antenna with parasitic monopoles for mobile terminals is described. The discussion on channel capacity shows that the antenna can be considered as a good candidate for MIMO systems. Furthermore, based on the study of current distributions, it is concluded that the technique is sensitive to relative positions between parasitic elements, and relative positions between active element and parasitic element. Finally, we also extend the technique to a tri-element antenna. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A Compact Wideband MIMO Antenna With Two Novel Bent Slits

    Publication Year: 2012 , Page(s): 482 - 489
    Cited by:  Papers (24)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2792 KB) |  | HTML iconHTML  

    A compact wideband multiple-input- multiple-output (MIMO) antenna is presented. The MIMO antenna consists of two symmetric monopoles with edge-to-edge separation of nearly 0.083 λ0 at 2.5 GHz. Two novel bent slits are etched into the ground plane. At the lower frequencies, the bent slits can reduce the mutual coupling and have slight effect on the reflection coefficient. At the higher frequencies, the slits can be considered as slit antennas to widen the impedance bandwidth because the two slits are coupled fed by two 50-Ω microstrip lines, respectively. Two triangles are cut from the ground plane. In this way, the reflection coefficient and isolation of the two slit antennas can be improved. A bandwidth of 92.7% with |S11| ≤ -10 dB and |S21 | ≤ -18 dB from 2.4 to 6.55 GHz is achieved. In order to provide quantifications for the performance of the MIMO antenna in real-world usage conditions, the effects of human hand and head on the performance of the MIMO antenna are investigated. The results show that the MIMO antenna serving as a phone antenna can provide spatial and pattern diversity to combat multipath fading. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Characteristic Mode Based Tradeoff Analysis of Antenna-Chassis Interactions for Multiple Antenna Terminals

    Publication Year: 2012 , Page(s): 490 - 502
    Cited by:  Papers (23)  |  Patents (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1997 KB) |  | HTML iconHTML  

    The design of multiple antennas in compact mobile terminals is a significant challenge, due to both practical and fundamental design tradeoffs. In this paper, fundamental antenna design tradeoffs of multiple antenna terminals are presented in the framework of characteristic mode analysis. In particular, interactions between the antenna elements and the characteristic modes and their impact on design tradeoffs are investigated in both theory and simulations. The results reveal that the characteristic modes play an important role in determining the optimal placement of antennas for low mutual coupling. Moreover, the ability of antenna elements to localize the excitation currents on the chassis can significantly influence the final performance. To demonstrate the effectiveness of the proposed approach, a dual-band, dual-antenna terminal is designed to provide an isolation of over 10 dB for the 900 MHz band without additional matching or decoupling structures. A tradeoff analysis of bandwidth, efficiency, effective diversity gain and capacity is performed over different antenna locations. Finally, three fabricated prototypes verify the simulation results for representative cases. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Multiple Antenna Systems With Inherently Decoupled Radiators

    Publication Year: 2012 , Page(s): 503 - 515
    Cited by:  Papers (15)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2523 KB) |  | HTML iconHTML  

    In multiple antenna systems mutual coupling needs to be minimized. We propose an alternative novel decoupling technique, investigating several multiple antenna configurations for small handsets through measurements and numerical simulations. The influence of different novel designs on performance metrics such as total loss, antenna isolation and envelope correlation coefficient are investigated. By varying antenna impedance bandwidth and antenna location with respect to the handset, both planar inverted F antenna (PIFA) and inverted F antennas (IFA) were investigated in different UMTS frequency bands in proximity with the user's body. Results show that antennas may experience very different losses and envelope correlation coefficients depending on their relative position with respect to the handset, as the influence of the user's hand is not symmetrical in most cases. Narrow-band antennas are inherently decoupled when integrated on the same handset, while also other parameters such as frequency duplex distance and interaction with the user's body influence the mutual coupling. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A Pattern Reconfigurable U-Slot Antenna and Its Applications in MIMO Systems

    Publication Year: 2012 , Page(s): 516 - 528
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1702 KB) |  | HTML iconHTML  

    A new compact pattern reconfigurable U-slot antenna is presented. The antenna consists of a U-slot patch and eight shorting posts. Each edge of the square patch is connected to two shorting posts via PIN diodes. By switching between the different states of the PIN diodes, the proposed antenna can operate in either monopolar patch or normal patch mode in similar frequency ranges. Therefore, its radiation pattern can be switched between conical and boresight patterns electrically. In addition, the plane with the maximum power level of the conical pattern can be changed between two orthogonal planes. Owing to a novel design of the switch geometry, the antenna does not need dc bias lines. The measured overlapping impedance bandwidth (|S11| <; -10 dB) of the two modes is 6.6% with a center frequency of 5.32 GHz. The measured radiation patterns agree well with simulated results. The antennas are incorporated in a 2 × 2 multiple-input-multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) system to demonstrate the improvement in system capacity. In the real-time MIMO-OFDM channel measurement, it is shown that compared to omnidirectional antennas, the pattern reconfigurable antennas can enhance the system capacity, with 17% improvement in a line-of-sight (LOS) scenario and 12% in a non-LOS (NLOS) scenario at a signal-to-noise ratio (SNR) of 10 dB. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Multiple Element Antenna Efficiency and its Impact on Diversity and Capacity

    Publication Year: 2012 , Page(s): 529 - 539
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1804 KB) |  | HTML iconHTML  

    A desirable characteristic of a multiple element antenna (MEA) is to be compact, but a smaller size tends to lead to higher ohmic and mutual coupling losses. A metric for the efficiency of the MEA would help clarify the tradeoffs between compactness and performance. In a MIMO/diversity antenna, the total efficiency seen at each port directly affects the signal-to-noise ratio (SNR) in the diversity branch. The SNR after diversity combining governs the performance of the diversity antenna system. In this paper, MEA efficiencies is therefore discussed and formulated in the context of mutual coupling and diversity combining. The impact of MEA efficiency on the diversity gain and the information theoretical capacity is also formulated and demonstrated using measurements of example MEAs. With these formulations, an equivalent number of idealized (lossless, uncorrelated, uncoupled, equal power) branches can be found for an MEA, and this defines the diversity order and the capacity order of the MEA. With this metric, the performance of different MEAs can be compared. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • On the Accuracy of Equivalent Circuit Models for Multi-Antenna Systems

    Publication Year: 2012 , Page(s): 540 - 547
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1733 KB) |  | HTML iconHTML  

    The equivalent circuit model of a general PEC antenna array is derived, based on a rigorous method of moments (MOM) formulation, indicating that network analysis is exact from the standpoint of electromagnetic wave theory. It is found that the network parameters (Z, Y, or S-parameters) for the transmit mode can be used for exact prediction of the receive-mode array response. Numerical and experimental examples illustrate the validity of the analytical results. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A Low-Cost MIMO Channel Sounder Architecture Without Phase Synchronization

    Publication Year: 2012 , Page(s): 548 - 556
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1577 KB) |  | HTML iconHTML  

    A MIMO channel sounder that does not require phase measurements is proposed. The system is based on parasitic antennas, with a single active element connected to a low expensive amplitude only receiver and a proper phase retrieval algorithm whose computation burden is compatible with today personal computers. Numerical simulations confirm the effectiveness of the approach. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Impact of Incomplete and Inaccurate Data Models on High Resolution Parameter Estimation in Multidimensional Channel Sounding

    Publication Year: 2012 , Page(s): 557 - 573
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2153 KB) |  | HTML iconHTML  

    Multidimensional channel sounding aims to estimate the geometrical structure of multi-path wave propagation in terms of directions of arrival/departure, Doppler shift, time delay, and complex polarimetric path weights. Maximum likelihood parameter estimation based upon an underlying data model is used to achieve high-resolution of the path parameters and, thus, renders possible an antenna independent channel characterization. However, any mismatch of the underlying data model to physical reality imposes limits to accuracy and reliability of the estimation. To cope with the limited resolution capability of the setup we are using a propagation data model that does not only contain discrete deterministic components but also a non-resolvable stochastic part. Joint estimation of both components considerably enhances the estimation quality and finally allows the interpretation as specular and diffuse contribution of multi-path propagation respectively. However, besides of noise influence, the achievable resolution is further limited by the accuracy of the data model that describes the measurement setup. Since the antenna characteristics are very susceptible to calibration and modeling errors, the directional estimates are most error-prone. We refer to the antenna array calibration procedure and discuss common pitfalls in high-resolution multi-path direction estimation that are related to inaccurate and/or incomplete device data model. Depending on the type of the antenna array (linear, circular) this will inherently produce biased and artificially spread angular estimates. Only with precise knowledge of the model errors the stochastic part can be identified as diffuse propagation component vs. modeling error. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A General Coupling-Based Model Framework for Wideband MIMO Channels

    Publication Year: 2012 , Page(s): 574 - 586
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2413 KB) |  | HTML iconHTML  

    A general coupling-based model framework for wideband multiple-input multiple-output (MIMO) channels is presented in this paper. Under this framework, the channel state information (CSI) tensor can be expressed by the product of a coupling tensor, a complex Gaussian tensor and three unitary matrices. The unitary matrices can be either eigenbases or steering matrices in different domains. The coupling tensor reflects the relationship between the column vectors of these unitary matrices. The complex Gaussian tensor is used to describe the small-scale fading. Several realizations of this framework are introduced, including the wideband Kronecker-based (WKB) model, the wideband eigenvalue-decomposition-based (WEB) model, the wideband virtual presentation (WVP) model and the wideband hybrid (WHY) model. To evaluate the performance of these models, channel measurements were carried out in different indoor scenarios both at Tsinghua University and Lund University. The results show that these models have good agreement with the measured data. Furthermore, we can see that the WHY model can provide a tradeoff between complexity and accuracy in channel synthesis. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Multi-Link MIMO Channel Modeling Using Geometry-Based Approach

    Publication Year: 2012 , Page(s): 587 - 596
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1595 KB) |  | HTML iconHTML  

    Geometry-based stochastic channel models (GSCMs) are extended to support multi-link simulations by applying the concept of common clusters. This novel approach aims to control the correlation between different links, inter-link correlation, by adjusting the amount of power simultaneously propagating via the same clusters in the different links. The behavior of common clusters is analyzed based on dual-link channel measurements, and a multi-link GSCM is developed based on common clusters. In addition, the effects that the common clusters have on inter-link correlation and on sum rate capacity are investigated based on simulations. Finally, comparison between simulations and measurements is done in order to indicate the validity of the proposed multi-link GSCM. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Land Mobile Satellite Dual Polarized MIMO Channel Along Roadside Trees: Modeling and Performance Evaluation

    Publication Year: 2012 , Page(s): 597 - 605
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1468 KB) |  | HTML iconHTML  

    We present a novel physical-statistical, generative model for the land mobile satellite (LMS), dual polarized, multiple-input-multiple-output (MIMO) channel along tree-sided roads. Said model is parameterized by means of a physical model based on the multiple scattering theory (MST) which accounts for the signal attenuation and scattering by trees. Moreover, finite-difference time-domain (FDTD) electromagnetic computations were performed to characterize the scattering pattern of an isolated tree, and to calculate the MIMO shadowing correlation matrix required by the model, and not provided by MST. This modeling framework also encompasses the single-input-multiple-output (SIMO)/space diversity case. To illustrate the capabilities of the developed model, time series were generated and used in system performance calculations. The obtained results give an insight into the advantages of dual polarized MIMO and SIMO/space diversity techniques in these very frequent scenarios and may help service providers in evaluating the technical feasibility of such systems. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Empirical-Stochastic LMS-MIMO Channel Model Implementation and Validation

    Publication Year: 2012 , Page(s): 606 - 614
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1599 KB) |  | HTML iconHTML  

    Land Mobile Satellite (LMS) networks, forming a key component of future mobile Internet and broadcasting, can benefit from Multiple-Input Multiple-Output (MIMO) techniques to improve spectral efficiency and outage. LMS-MIMO networks can be obtained using multiple satellites with single polarization antennas with spatial multiplex channel coding, or by a single satellite with dual polarization antennas providing polarization multiplex channel coding. In this paper, a guide is presented showing the steps required to implement a simple empirical-stochastic dual circular polarized LMS-MIMO narrowband channel model with validation both with and without a line of sight. The model is based on an S-band tree-lined road measurement campaign using dual circular polarizations at low elevations. Application of the model is aimed at LMS-MIMO physical layer researchers and system designers, who need an easy to implement and reliable model, representative of typical LMS-MIMO channel conditions. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Effectiveness of Relay MIMO Transmission by Measured Outdoor Channel State Information

    Publication Year: 2012 , Page(s): 615 - 623
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1884 KB) |  | HTML iconHTML  

    This paper investigates the effectiveness of the multiple input multiple output (MIMO) transmission with the aid of relay nodes by using measured outdoor channel state information (CSI) for the source, relay, and destination which are used in cooperative transmission. Single/multi-user MIMO (SU/MU-MIMO) systems have attracted much attention as the technology enhances the channel capacity with a limited frequency band. In this paper, cooperative transmission using the relay station is applied to SU/MU-MIMO systems: Relay MIMO transmission. Although the performance of relay MIMO transmission is affected by the actual propagation environment, the performance has not yet been investigated using measured propagation channel data in outdoor scenarios. In this paper, we demonstrate that the channel capacity with the relay MIMO transmission can be improved compared to the conventional MIMO transmission without the relay nodes, especially in multi-user scenarios. Moreover, orthogonal polarization is introduced and its effectiveness is shown in further improving the channel capacity of relay MIMO transmission. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Single and Multi-User Cooperative MIMO in a Measured Urban Macrocellular Environment

    Publication Year: 2012 , Page(s): 624 - 632
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1352 KB) |  | HTML iconHTML  

    We study the potential benefits of cooperative multiple-input multiple-output signaling from multiple coherent base stations with one or more mobile stations in an urban macrocellular environment at 2.66 GHz. The analysis uses fully-coherent measurements of the channel from three base stations to a single mobile station equipped with four antennas. The observed channels are used to explore the gains in capacity enabled by cooperative base station signaling for point-to-point and multi-user communications. The analysis shows that for point-to-point links, the average capacity for cooperative signaling is 53% higher than that achieved for a single base station. For downlink and uplink communication with three mobile users, cooperative signaling yields average sum rate increases of 91% and 63%, respectively. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • User Influence on MIMO Channel Capacity for Handsets in Data Mode Operation

    Publication Year: 2012 , Page(s): 633 - 643
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1819 KB) |  | HTML iconHTML  

    The current paper concerns realistic evaluation of the capacity of the MIMO channel between a BS and handheld device, such as a PDA or smartphone, held in front of the user's body (data mode). The work is based on measurements of the MIMO channel between two widely separated BSs in a micro-cellular setup, and six handsets located in an indoor environment. The measurements are done simultaneously in both the 773.5-778.5 MHz and 2250-2350 MHz bands, and from the two BSs. The handsets are realistic types and were measured both in free space and with twelve different users, using both one and two hands. The random capacities of the channels are evaluated in terms of outage capacity. For an SNR of 10 dB, median capacities in free space of about 4.4-4.7 bit/s/Hz for the low band and about 3.3-3.8 bit/s/Hz for the high band were found. The mean decrease in outage capacity due to the user was found to be up to about 2.2 bit/s/Hz, depending on the band and handset. More results are presented in the paper. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Exposure Compliance Methodologies for Multiple Input Multiple Output (MIMO) Enabled Networks and Terminals

    Publication Year: 2012 , Page(s): 644 - 653
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1339 KB) |  | HTML iconHTML  

    Multiple input multiple output (MIMO) enabled handsets and base-stations feature antenna systems that generate electromagnetic fields for which relevant exposure standards and guidelines do not explicitly define compliance testing methodologies. Here, through computational modeling, we explore several field summation schemes for evaluating such exposures and propose compliance testing methodologies that limit the degree of exposure under/over-estimation for both base stations and handsets. The methodologies rely on scalar field probe measurements thus avoiding significant equipment upgrades and are applicable to cases where access to signals from each MIMO antenna element can be arranged. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • MIMO Transmission Using a Single RF Source: Theory and Antenna Design

    Publication Year: 2012 , Page(s): 654 - 664
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2620 KB) |  | HTML iconHTML  

    An approach for transmitting multiple signals using a single switched parasitic antenna (SPA) has been recently reported. The idea there is to map the signals to be transmitted onto a set of basis functions that serve as “virtual antennas” in the beamspace (i.e., wavevector) domain. In this paper, we generalize the derivation of the antenna pattern basis functions regarding a three-element SPA of arbitrary radiating elements, within a symmetric array topology, for multiplexing signals in the wavevector domain (using different beampatterns) rather than in the hardware antenna domain with multiple feeding ports. A fully operational antenna system example is modeled, optimized regarding its return loss and the power imbalance between the basis functions, and finally realized. The measurements of the SPA show good agreement with the simulated target values, revealing an accurate design approach to be adopted as a fast SPA prototyping methodology. The SPA has been successfully employed for multiplexing two binary phase-shift-keying (BPSK) datastreams over-the-air, thus paving the way for practically compact and highly efficient MIMO transceiver designs. View full abstract»

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

Aims & Scope

IEEE Transactions on Antennas and Propagation includes theoretical and experimental advances in antennas.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief                                                 Kwok W. Leung