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Antennas and Propagation (EUCAP), Proceedings of the 5th European Conference on

Date 11-15 April 2011

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Displaying Results 1 - 25 of 946
  • [Title page]

    Publication Year: 2011 , Page(s): i
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  • Program

    Publication Year: 2011 , Page(s): ii - xcviii
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  • Committees

    Publication Year: 2011 , Page(s): xcix - c
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  • Non-specular scattering modeling for THz propagation simulations

    Publication Year: 2011 , Page(s): 1 - 5
    Cited by:  Papers (4)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (429 KB) |  | HTML iconHTML  

    In this paper, we present an approach for the modeling of non-specular scattering at rough surfaces in the THz frequency range by means of the Kirchhoff scattering theory. The practical implementation of the Kirchhoff model in a ray tracing algorithm is discussed. Ray tracing simulation results are compared with measurements for the purpose of validation. The size of the relevant active scattering region of a rough surface is investigated. View full abstract»

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  • Stochastic scattering model for the application of SBR to rough surfaces

    Publication Year: 2011 , Page(s): 6 - 9
    Cited by:  Papers (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1181 KB) |  | HTML iconHTML  

    A large variety of simulation tools for calculating scattered fields have been published in literature. Basically, there are two main approaches, the so-called numerically exact or full-wave solutions, e.g. using Method of Moments (MoM), and the high-frequency or asymptotic solutions, e.g. using rays for modelling propagation paths. However, most of these simulation tools are limited to perfectly conducting surfaces or homogeneous dielectric bodies with ideally smooth surfaces. The present paper studies the enhancement of a ray tracing code based on the well-known Shooting-and-Bouncing-Rays (SBR) technique for calculating scattered fields of arbitrary objects, whose surfaces are characterised by roughness parameters. View full abstract»

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  • On the practical applicability of series expansions for Kirchhoff diffractals

    Publication Year: 2011 , Page(s): 10 - 13
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (240 KB) |  | HTML iconHTML  

    Use of the Kirchhoff approach allows expressing the electromagnetic field scattered by a fractal surface in terms of two series with different convergence regions. Convergence properties of these series and problems arising in their numerical evaluation have been presented in recent literature. In particular, suitable truncation criteria have been devised, which allow practical use of these two series expansions for computation of the scattered field with a controlled error. Based on the analysis provided by the recent literature, in this work an algorithm is presented that, given the illumination and surface roughness parameters, computes the scattered power density by automatically selecting the most appropriate series and truncation criterion. View full abstract»

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  • Target classification through time-reversal operator analysis using ultrawideband electromagnetic waves

    Publication Year: 2011 , Page(s): 14 - 18
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (503 KB) |  | HTML iconHTML  

    We study the scattering matrices employed in time-reversal (TR) imaging algorithms in an attempt to provide additional classification information for scatterers with different shapes and characteristics. Specifically, we apply the eigenspace analysis to the so-called TR operator (TRO) and singular value analysis to the recently introduced space-frequency scattering matrices obtained for metallic and non-metallic objects with different cross-sections, aspect ratios and orientations. It is reported that for scatterers with cross sections less than half wavelength and unity aspect ratios, singular value distributions do not provide enough shape distinguishing information. On the other hand, when the cross-sections are larger and while operating at the higher portion of the frequency spectrum, singular value distributions deviate from each other providing shape distinguishing characteristics. View full abstract»

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  • System simulation of a localization system based on power level detection with distributed antennas

    Publication Year: 2011 , Page(s): 19 - 23
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (548 KB) |  | HTML iconHTML  

    Estimation of the transmitter position based on the received signal strength (RSS) appears to be an attractive approach for indoor applications. However, strong power level fluctuations within buildings decrease the accuracy and reliability considerably. In this paper we present an extensive study based on simulations by applying a distributed antenna system for localization purposes in indoor scenarios. The basic idea is to use power level detection determined from two access points attached to the cable heads of the system. This positioning approach has the advantage that only marginal additional hardware is required to implement the localization functionality. For planning purposes a complete system simulation tool has been developed to analyze the impact of different environments on the positioning accuracy. The simulation results were verified with measurements carried out with a developed antenna prototype. View full abstract»

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  • Polarization investigation of rough surface scattering for THz propagation modeling

    Publication Year: 2011 , Page(s): 24 - 28
    Cited by:  Papers (5)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (409 KB) |  | HTML iconHTML  

    This paper presents the modeling of both coherent and incoherent scattering processes from rough surfaces at THz frequencies with the focus on polarization aspects. In a ray tracing algorithm, coherent scattering is implemented based on the Kirchhoff theory whereas a perturbation approach is used for the incoherent contribution. Geometrical depolarization is accounted for by means of the Jones calculus. Ray tracing is applied in a small indoor scenario to demonstrate the influence of depolarization on THz propagation channels. View full abstract»

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  • Modelling polarimetric effects of precipitation on spaceborne side-looking aperture radar response

    Publication Year: 2011 , Page(s): 29 - 33
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (419 KB) |  | HTML iconHTML  

    Precipitating clouds can have significant effects on both amplitude and phase of the signal received by spaceborne microwave sensors, especially if operating at frequencies above C-band. The evaluation of these effects is more complicated on Synthetic Aperture Radar (SAR) systems, due to their slant observing geometry. The signal received by spaceborne SAR systems in presence of precipitating cells is a combination of surface and volumetric scattering, reduced by path attenuation and largely dependent on frequency, polarization and spatial distribution of hydrometeors. Moreover, the nominal SAR resolution (of the order of meters) is reduced (to the order of hundreds meters) due to the random nature of the moving distributed atmospheric target. In this work a numerical forward model of spaceborne SAR response due to precipitating clouds is introduced, using a high-resolution mesoscale atmospheric numerical model. This modelling framework aims at improving the understanding of the correlation between SAR retrieved signals and precipitation contents. The developed simulator, quite flexible in terms of structure and configuration, is suitable to analyze X, Ku or Ka spaceborne observations, adopted for several current or planned spaceborne SAR missions. View full abstract»

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  • Landmine detection using ground penetrating radar and polarimetric Synthetic Aperture Radar

    Publication Year: 2011 , Page(s): 34 - 38
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1193 KB) |  | HTML iconHTML  

    In this paper, the data processing based on polarimetric features extraction from Synthetic Aperture Radar (SAR) processed data is discussed. For this purpose, fully polarimetric data were collected using the ultra-wideband Ground Penetrating Radar (GPR) and quad ridged horn antenna. The measurement of plastic landmine, metallic pipe and rocks buried in the sand was carried out so that three dimensional data correction and visualization could be applied. Since the landmine is detected in the presence of a metallic target, a standard GPR processing does not lead to satisfactory results. Therefore, polarization and orientation features were obtained by means of the polarimetric decomposition in order to classify and detect various objects. View full abstract»

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  • Estimation of the radiation pattern of finite arrays of waveguide-fed apertures from the transmitting characteristics of an isolated element

    Publication Year: 2011 , Page(s): 39 - 43
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (500 KB) |  | HTML iconHTML  

    This work presents a simple method to estimate the radiation pattern of finite arrays of waveguide-fed apertures on an infinite ground plane. This method is based on the theory of Minimum-Scattering Antennas and the Generalized Scattering Matrix of a finite array in terms of spherical modes. Waveguide-fed apertures can be considered as short-circuited minimum-scattering antennas just in the aperture. This way, the scattering characteristics of an isolated aperture can be deduced from its transmitting properties if the reflection coefficient is known. Therefore, the generalized scattering matrix in terms of spherical modes of an isolated aperture can be obtained. Finally, the generalized scattering matrix of the finite array can be calculated by applying translation and rotation of spherical modes. View full abstract»

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  • On the design of NFC antennas for contactless payment applications

    Publication Year: 2011 , Page(s): 44 - 47
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (2208 KB) |  | HTML iconHTML  

    The increasing interest in using Near Field Communications (NFC) technology at 13.5MHz is growing rapidly in the area of contactless payments, as well as numerous other applications, between devices that are within 10cm distance apart. However, there is growing concern that the use of such devices for contactless payments invites problems with regards to using metallic objects in the vicinity of the two devices to act as “rogue” antennas, which eavesdrop information during a financial transaction is taking place. This paper presents aspects of designing H-antennas both for the two devices communicating while also identifying the means by which rogue antennas can be created by exploiting real life metallic structures. In this paper, a shopping trolley is taken as an example. View full abstract»

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  • Diamagnetic metasurfaces for performance enhancement of microstrip patch antennas

    Publication Year: 2011 , Page(s): 48 - 52
    Cited by:  Papers (6)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1122 KB) |  | HTML iconHTML  

    A cost-effective solution for enhanced performance of microstrip patch antennas is proposed in this paper. The squarering type metasurfaces are introduced and proved to have diamagnetic characteristics by using two retrieval methods. The conventional probe-fed linearly and circularly polarized patch antennas are shown to have simultaneous improvement in terms of broadside emission, bandwidths and efficiencies. View full abstract»

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  • On the impact of arbitrary nozzle or dome configurations on dielectric endfire antenna performance in industrial radar level gauging

    Publication Year: 2011 , Page(s): 53 - 57
    Cited by:  Papers (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1453 KB) |  | HTML iconHTML  

    Dielectric antennas commonly used in radar based industrial level gauging often need to cross metallic nozzles or domes with arbitrary dimensions. In this article, the detrimental effects of such configurations are investigated. Two antennas incorporated into nozzles of different lengths and diameters are exemplarily evaluated to reveal the variations in antenna parameters such as the peak directivity as well as in the total measurement performance in a well established test scenario in industrial level measurement emulated by a radar system simulator. It is shown that it is beneficial to minimize the nozzle effects by careful antenna design, like e.g. by utilizing tightly guiding dielectric waveguides to cross the nozzle or by making use of optimized metallic launching horns in order to control the excitation of parasitic eigenmodes inside the nozzle. View full abstract»

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  • MIMO OTA optical measurement device

    Publication Year: 2011 , Page(s): 58 - 61
    Cited by:  Papers (5)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1238 KB) |  | HTML iconHTML  

    Following the growing interest in Over The Air testing of Multiple Input Multiple Output handset antenna systems, this paper presents a non-galvanic measurement tool for early antenna performance estimation in the prototyping and testing stages of the development process. The necessity for removing the coaxial cables, is here demonstrated with an example MIMO parameter - correlation. It is found by simulations, that the presence of cables not only completely changes this parameter, but the concrete cable position can also be very significant. The device proposed here, uses two parallel RF-over-fiber channels with low power consumption in wideband operation. The achieved dynamic range is up to 60 dB with acceptable isolation for two particular design frequencies and up to one hour of operation on a single battery charge. The total electrical dimensions are 40×40×10 mm, making it suitable for typical phone mock-ups. It can be used in both anechoic, as well as stirred mode chambers. View full abstract»

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  • Determination of maximum Doppler shift in reverberation chamber using level crossing rate

    Publication Year: 2011 , Page(s): 62 - 65
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (410 KB) |  | HTML iconHTML  

    Doppler spread has been observed in reverberation chambers (RC) with moving mode-stirrers. In this paper, we propose a simple method to determine the maximum Doppler frequency shift in the RC by using level crossing rate (LCR). The Doppler spread bandwidth is twice of the maximum Doppler frequency. RC loading effect on Doppler spread is also studied in this paper. Using the method, it is found that maximum Doppler spread bandwidth tends to reduce when lossy objects are located into the RC, and the larger reduction the more larger lossy objects. View full abstract»

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  • Estimation of peak spatial-average SAR of inverted F-antenna on metal plate using lightweight phantom composed of wave absorber

    Publication Year: 2011 , Page(s): 66 - 70
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (476 KB) |  | HTML iconHTML  

    A simplified method for measuring the specific absorption rate (SAR) is required in order to limit the spatial-average SAR for mobile devices in Japan. In this paper, a simplified SAR measurement method involving the use of a flat-plane lightweight phantom composed of a radio wave absorber is proposed. The utility of the lightweight phantom and the feasibility of using the proposed measurement method along with the lightweight phantom are verified. Finally, the peak spatial-average SAR of an inverted F-antenna mounted on a metal plate is estimated using the proposed measurement method. View full abstract»

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  • Upper bounds on fixed-geometry wheeler cap efficiency measurements - Part I: System model and rectangular cavities

    Publication Year: 2011 , Page(s): 71 - 75
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (977 KB) |  | HTML iconHTML  

    Antenna efficiency is a critical performance metric, but also difficult to determine accurately. Wheeler's elegant idea is a simple, fast, repeatable and accurate technique of measuring small antenna efficiency inside shielded cavities. Natural cavity resonances violate the Wheeler cap principle, produce negative efficiency values, and reduce the measurable bandwidth (BW) and/or size of the antenna. Resonances can be avoided by using variable-geometry cavities; however, these require precise manufacturing to avoid energy leakage. Fixed-geometry cavities are easier to build and far more cost-efficient. This two-part study estimates the limits of dip-free efficiency measurements for planar antennas inside fixed-geometry caps. Part I firstly describes the joint antenna-cavity system model enabling the analyses. This is followed by a treatment of rectangular cavities, which display coherent measurable BWs in the range 15-33% for antenna sizes 0.5-0.78 times the wavelength. Finally, part I shows that the methodology can be readily extended to arbitrary antennas. View full abstract»

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  • Upper bounds on fixed-geometry wheeler cap efficiency measurements - Part II: Spherical and cylindrical cavities

    Publication Year: 2011 , Page(s): 76 - 80
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1375 KB) |  | HTML iconHTML  

    A system model has been developed for the analytical and numerical treatment of the Wheeler cap technique. The model projects the properties of the antenna-under-test on the properties of the cavity, and was used in part I of the study to examine the performance of constant-size rectangular cavities. E/M simulations verified the model. Part II proceeds in the same framework and completes this two-part study, which estimates the limits of resonance-free efficiency measurements of planar antennas inside fixed-geometry Wheeler caps through a unified deterministic design methodology for 3 types of cavities. The focus is on the analytical and numerical treatment of spherical and cylindrical cavities. Spherical caps can provide coherent measurable bandwidths (BWs) in the range 28-41% for antenna sizes 0.5-0.85 times the wavelength. Cylindrical cavities are also versatile performers and display coherent measurable BWs in the range 20-40% for antenna sizes 0.5-0.78 times the wavelength. Electrically small antennas can secure measurable BWs up to 87% in the spherical case and up to 76% in the cylindrical one, when the cavities are operated below cut-off. View full abstract»

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  • Total scattering cross section improvements from electromagnetic reverberation chambers modeling and stochastic formalism

    Publication Year: 2011 , Page(s): 81 - 85
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (757 KB) |  | HTML iconHTML  

    This article is dedicated to deterministic and stochastic improvements for TSCS computations. Firstly, the Total Scattering Cross Section (TSCS) measurements are achieved in a numerical Reverberation Chamber (RC) for different targets. From a theoretical point of view, a free-space environment (for instance an anechoic chamber modeled numerically by absorbing boundary conditions) jointly with plane waves stimulations are needed to compute the TSCS. The developed method allows predicting the TSCS from few simulations in RC. Secondly, in this paper, a stochastic collocation technique is used to accurately and efficiently compute the TSCS statistical moments varying randomly given parameters. Thus, the presented foundations and numerical results demonstrate the ability of the method to integrate stochastic variations in TSCS computing. The agreement from stochastic (uncertainties around targets sizes) results is obtained considering the convergence of the collocation technique. View full abstract»

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  • FDTD channel modelling with time domain huygens' technique

    Publication Year: 2011 , Page(s): 86 - 89
    Cited by:  Papers (3)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (517 KB) |  | HTML iconHTML  

    Much interest is currently being shown in mm-wave high data rate, short range communication links. The modelling of these types of links presents considerable challenges. In this paper, a 60 GHz link consisting of two Cavity Backed Slot antennas, the terminals on which they are mounted and the intervening environment, is modelled using an enhanced FDTD technique. This type of problem can be expensive in computer resources because of the existence of small geometrical detail and also a large computational space. To improve on this, the problem is split into three parts which are linked using a Time Domain Huygens (TDH) approach. An improvement of around 56 % is obtained in the overall run time compared to a direct FDTD run. The approach has much potential and is suitable to be applied in larger and more complex communications links. View full abstract»

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  • Considerations on cloud attenuation at 100 and 300 GHz for propagation measurements within the TeraSense project

    Publication Year: 2011 , Page(s): 90 - 94
    Cited by:  Papers (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (395 KB) |  | HTML iconHTML  

    Propagation conditions at frequencies of between 100 GHz and 30 THz, also known as the THz range, are severely affected by the influence of the composition and phenomena of the troposphere. This paper is focused on important aspects of cloud attenuation under non-rainy conditions at 100 GHz and 300 GHz. Estimations of cloud and total attenuation are computed using 3-year meteorological data from Madrid, Spain, on the basis of well-accepted absorption models and considering a Rayleigh regime. Moreover, with the aim of deploying radiometric instruments at both frequencies, some expected values of sky brightness temperature and total attenuation are also presented. View full abstract»

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  • Conversion of evanescent waves into propagating modes by passing through a metamaterial prism: An iterative approximation method

    Publication Year: 2011 , Page(s): 95 - 99
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (385 KB) |  | HTML iconHTML  

    An iterative algorithm is presented to provide a simple but approximate solution to the excitation of an infinite wedge by an evanescent wave. The device is constructed from hyperbolic metamaterial and this contributes in the partial conversion of the evanescent field into multiple propagating modes. The effectiveness and the performance of this transformation is expressed through a novel power ratio. Its variation with respect to the geometrical and material parameters of the problem is observed, while certain conclusions are presented and discussed. View full abstract»

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  • A physical analytical model for the connectivity evaluation of dual-polarized millimeter-wave multi-hop backhaul networks

    Publication Year: 2011 , Page(s): 100 - 104
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1020 KB) |  | HTML iconHTML  

    The subject of this paper is the presentation of an analytical physical model for the connectivity evaluation of dual polarized multi-hop wireless backhaul networks operating at frequencies above the 10GHz. Physical phenomena related to propagation of millimeter radio waves through the atmosphere cause signal impairments and depolarization. These phenomena strongly affect the topology and the connectivity of a wireless multi-hop network. Taking into account the dominant propagation conditions at these frequencies and the impact of signal depolarization, we calculate the node isolation probability and the critical node density. We will show that dual polarization scarcely aggravates the node isolation probability and the network's connectivity so that it can be considered as a major solution for increasing the links throughput at the future backhaul networks. The sensitivity of isolation probability and critical node density on frequency of operation, transmission power and climatic conditions is finally investigated. View full abstract»

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